source water. As discussed in section VI.C of this preamble, Occurrence
and Predictive Modeling, the model developed for this economic analysis
considers the effect of GWR both before and during implementation of
the RTCR. The RTCR T&C document included estimates of unit costs for
the major components of the RTCR that were obtained from the advisory
committee technical workgroup and vendors, including labor, monitoring,
assessments, and corrective actions.
    US Census data were used to estimate population per household and
to characterize sensitive subpopulations. Lastly, knowledge and
experience from stakeholders helped to inform the assumptions that were
made for the analysis.
    A more detailed discussion of these data sources and how EPA used
them are included in the RTCR EA.

C. Occurrence and Predictive Modeling

    EPA used the data to develop an occurrence and predictive model for
PWSs serving 4,100 or fewer people based primarily on the 2005 Six-Year
Review 2 data. The model predicts changes in total coliform and E. coli
occurrence, Level 1 and Level 2 assessments (based on simulated
monitoring results), corrective actions, and violations over time. EPA
developed another simpler predictive model for PWSs serving more than
4,100 people that predicts Level 1 and Level 2 assessments (based on
2005 violation data from SDWIS/FED), corrective actions, and violations
over time, but not total coliform and E. coli occurrence. EPA modeled
systems serving more than 4,100 people separately because the Six-Year
Review 2 data for larger PWSs were not as robust as the data for the
smaller systems. In addition, while the RTCR includes new monitoring
requirements for PWSs serving 4,100 people or fewer, monitoring
requirements for systems serving greater than 4,100 people remain
essentially unchanged from the 1989 TCR. This section briefly discusses
the structures of each of the two models and how they used available
data, information, and assumptions to make predictions over time
resulting from the regulatory options.
    Chapter 5 of the RTCR EA includes a more detailed description of
the occurrence and predictive model used for PWSs serving 4,100 or
fewer people, and the other simpler predictive model used for PWSs
serving greater than 4,100 people.
1. Model Used for PWSs Serving <= 4,100 People
    The occurrence and predictive model used for PWSs serving 4,100 or
fewer people has two components. The first component of the model
characterized how the presence or positive rates of total coliform and
E. coli detections vary across the population of small (serving 4,100
or fewer people) public water systems in the US. These rates vary by
the type of sample (routine or repeat), by analyte (total coliforms or
E. coli), and by system type (CWS, NCWS, or TNCWS) and size. The second
component of the model used the total coliform and E. coli occurrence
distributions to simulate a set of nationally-representative systems
within the context of the three regulatory options (1989 TCR, RTCR, and
Alternative) to predict changes in total coliform and E. coli
occurrence, triggers, assessments, corrective actions over time, and
violations.
    The model assumed that the national occurrence of total coliforms
and E. coli has reached a steady state in recent years under the 1989
TCR. It assumed that cycles of normal deterioration and repair/
replacement are occurring at the individual system level, but the
numbers of violations at the national level have remained relatively
unchanged. This assumption is based on evaluation of SDWIS/FED
violation data. Exhibit VI-1 presents the number of PWSs with
violations from 2001-2007 under the 1989 TCR which shows that national
violation rates have remained relatively steady over recent years. The
RTCR will affect this steady state, likely resulting in a reduction of
the underlying occurrence and associated violations.

                                         Exhibit VI-1--Number of PWSs With Violations by System Type (2001-2007)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Year
                           PWS Type                           ------------------------------------------------------------------------------------------
                                                                   2001         2002         2003         2004         2005         2006         2007
--------------------------------------------------------------------------------------------------------------------------------------------------------
Acute MCL Violations
--------------------------------------------------------------------------------------------------------------------------------------------------------
CWS..........................................................          143          144          185          171          151          171          171
NTNCWS.......................................................           51           53           70           58           65           68           45
TNCWS........................................................          261          278          322          351          349          361          295
                                                              ------------------------------------------------------------------------------------------

    All......................................................          455          475          577          580          565          600          511
Non-Acute MCL Violations
--------------------------------------------------------------------------------------------------------------------------------------------------------
CWS..........................................................        2,074        2,110        2,204        2,314        2,196        2,095        1,996
NTNCWS.......................................................          601          679          725          750          753          735          655
TNCWS........................................................        2,707        2,934        3,036        3,132        3,039        3,244        3,209
                                                              ------------------------------------------------------------------------------------------
    All......................................................        5,382        5,723        5,965        6,196        5,988        6,074        5,860
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: PWSs counts are of systems that had at least one violation during the year.
Source: SDWIS/FED annual data for period ending 3rd quarter 2001-2007. OH, US territories, Tribal PWS data excluded.

    Before the RTCR goes into effect, GWR implementation begins and is
also expected to affect the steady state. To estimate the effects that
GWR implementation is expected to have on present steady state
conditions, EPA used the occurrence and predictive model to simulate
five years of implementation of the 1989 TCR with the GWR, which became
effective in December 2009. EPA assumed these five years to account for
the approximately two years before the expected promulgation date of
the final RTCR and an additional three years after that until the RTCR
effective date. The assumptions made to account for the GWR are
described in detail in the in the RTCR EA and summarized in Exhibit VI-
2.

      Exhibit VI-2--Summary of Major Assumptions for Simulating GWR
                             Implementation
------------------------------------------------------------------------
             GWR provision                 Modeling approach/assumption
------------------------------------------------------------------------
Triggered Monitoring: Ground water       Current model used same
 systems not providing 4-log treatment    probabilities used in GWR EA
 for viruses that have total coliform-    (USEPA 2006a) to predict
 positive samples under the 1989 TCR      whether source water samples
 are required to take source water        will be E. coli-positive.
 samples and test for a fecal            Ground water systems required
 indicator. If the sample is positive,    to conduct corrective action
 they must take an additional 5 source    due to monitoring results will
 water samples (unless the State          either install disinfection or
 requires corrective action). If any of   implement a nondisinfecting
 these is positive, they must conduct     corrective action as described
 corrective action.                       in the RTCR EA.
                                         Ground water systems installing
                                          disinfection will draw from
                                          the probability distributions
                                          for total coliforms and E.
                                          coli for disinfected systems
                                          for the remainder of analysis.
                                         Ground water systems
                                          implementing a nondisinfecting
                                          corrective action will
                                          experience no positive samples
                                          for the remainder of the year
                                          plus two additional years and
                                          will experience a 75 \1\
                                          percent reduction in
                                          occurrence for five additional
                                          years.
Sanitary Surveys: GWR includes Federal   Model did not explicitly
 sanitary survey requirements for all     simulate sanitary surveys or
 ground water systems, and requires       their results. Rather, it
 States to perform regular                assumed that the new sanitary
 comprehensive sanitary surveys           survey provisions will result
 including eight critical elements.       in 10 percent \2\ reduced
                                          occurrence of total coliforms
                                          universally for entire
                                          analysis.
Compliance Monitoring: Ground water      Model did not explicitly
 systems that provide 4-log treatment     simulate compliance
 for viruses must demonstrate that they   monitoring. Rather, it assumed
 are providing this level of treatment    that the provision will result
 by conducting compliance monitoring.     in 10 percent \3\ reduced
                                          occurrence of total coliforms
                                          for those ground water systems
                                          that are conducting compliance
                                          monitoring once assumed 4-log
                                          treatment for viruses begins.
------------------------------------------------------------------------
1 2 3 Assumption reflects EPA best professional judgment.
Source: RTCR EA (USEPA 2012a) as informed by GWR EA (USEPA 2006a).

    Actual reductions in occurrence from the implementation of GWR
requirements may differ from what is presented here. However, based on
assumptions used in this model, the analysis of how the RTCR and
Alternative option perform relative to each other are not affected.
    In addition to capturing the effect of implementation of GWR
requirements with the 1989 TCR for a five-year period of analysis, the
model captures an additional 25 years with the 1989 TCR, the RTCR
option, and the Alternative option. Along with changes in total
coliform and E. coli occurrence, the model predicts behavioral changes:
the number of Level 1 and Level 2 assessments (and associated Level 1
or Level 2 corrective actions) to be performed, further resulting
adjustments to occurrence, and changes in sampling regimens as systems
qualify for reduced monitoring requirements. The assumptions used to
simulate RTCR implementation are detailed in the RTCR EA and summarized
in Exhibit VI-3.

     Exhibit VI-3--Summary of Major Assumptions for Simulating RTCR
                             Implementation
------------------------------------------------------------------------
        RTCR Provision                Modeling Approach/Assumption
------------------------------------------------------------------------
Level 1 Assessment...........  Model simulates sampling and sampling
                                results and determines which PWSs will
                                be triggered to conduct an assessment.
                               Sanitary defects are found in 10 percent
                                \1\ of assessments (represents net
                                increase over the 1989 TCR).
                               All sanitary defects are corrected. Model
                                selects from distribution of potential
                                corrective actions as explained in
                                chapter 7 of the RTCR EA (USEPA 2012a).
                               PWSs implementing a corrective action as
                                a result of a Level 1 assessment
                                experience no positive samples for the
                                remainder of the year plus one
                                additional year and will experience 50
                                percent \2\ reduction in occurrence for
                                three additional years.
Level 2 Assessment...........  Model simulates sampling and sampling
                                results and determines which PWSs will
                                be triggered to conduct an assessment.
                               Sanitary defects will be found in 10
                                percent \3\ of assessments (represents
                                net increase over the 1989 TCR).
                               All sanitary defects are corrected. Model
                                selects from distribution of potential
                                corrective actions as explained in
                                chapter 7 of the RTCR EA (USEPA 2012a).
                               PWSs implementing a corrective action as
                                a result of a Level 2 assessment will
                                experience no positive samples for the
                                remainder of the year plus two
                                additional years and will experience 75
                                percent \4\ reduction in occurrence for
                                five additional years.
------------------------------------------------------------------------
1 3 Assumption based on conversation with State representatives with on-
  the-ground experience.
2 4 Assumption reflects EPA best professional judgment.
Note: EPA recognizes that there is a large uncertainty with the
  assumptions. Sensitivity analyses showed that the fundamental
  conclusions of the economic analysis do not change over a wide range
  of assumptions tested.
Source: RTCR EA (USEPA 2012a)

    EPA made different assumptions for the effectiveness of assessments
and subsequent corrective actions to account for the differences
between the two types of assessments. The Level 2 assessment is a more
comprehensive investigation that may result in finding more substantial
problems than what may be found during a Level 1 assessment, and for
that reason the corrective actions that result from a Level 2
assessment were modeled to result in corrective action measures that
are generally more expensive and have bigger and longer lasting effects
than those of the Level 1 assessments. EPA conducted sensitivity
analyses around the key assumptions summarized in Exhibit VI-2 as
discussed in section VI.L of this preamble, Uncertainties in the
Benefit and Cost Estimate for the RTCR.
2. Model Used for PWSs Serving > 4,100 People
    For systems serving more than 4,100 people, EPA estimated violation
and trigger rates using SDWIS/FED because the Six-Year Review 2 data
for PWSs serving more than 4,100 people were not as robust as the Six-
Year Review 2 data for systems serving 4,100 or fewer people. EPA did
not quantify changes in violation or trigger rates for systems serving
more than 4,100 people among the 1989 TCR, RTCR, and Alternative
options because of: (1) Limited Six-Year Review 2 data to characterize
these systems, (2) the essentially unchanged monitoring requirements
across options for these systems, and (3) the level of effort already
occurring to implement the 1989 TCR.

D. Baseline Profiles

    The estimate of baseline conditions that EPA developed provides a
reference point for understanding net impacts of the RTCR.
    Compliance with the GWR began in December 2009, and the expected
compliance date of the RTCR is approximately six years following
commencement of the GWR implementation. The majority of PWSs are ground
water systems and these systems are expected to be affected by the GWR.
Because GWR implementation prior to the effective date of RTCR is
expected to cause changes to ground water systems, the baseline
conditions that EPA developed for ground water systems account for the
expected effects of the GWR.
    For PWSs serving more than 4,100 people, EPA assumed that present
conditions, as reflected in 2005 SDWIS/FED data, are an appropriate
representation of the conditions that are likely to exist when the RTCR
becomes effective. EPA assumed that a steady state exists at the
national level.
    The number of ground water PWSs that disinfect is expected to
change during implementation of the GWR before the expected rule
compliance date of the RTCR. Exhibit VI-4 shows the estimated baseline
number of the ground water PWSs at the RTCR compliance date.

       Exhibit VI-4--Estimated Baseline Number of Ground Water Systems and Disinfection Status at Compliance Date (3 Years Post RTCR Promulgation)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Number of ground water PWSs (post-GWR)
                                             -----------------------------------------------------------------------------------------------------------
                  PWS Size                                    CWS                               NTNCWS                               TNCWS
                                             -----------------------------------------------------------------------------------------------------------
                                                Disinfecting    Non-disinfecting    Disinfecting    Non-disinfecting    Disinfecting    Non-disinfecting
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100.......................................             6,190             5,748             2,938             5,888            13,753            46,447
101-500.....................................             9,311             4,581             2,776             3,837             5,451            13,824
501-1,000...................................             3,512               955               873               845               684             1,279
1,001-4,100.................................             5,422             1,021               547               265               274               343
4,101-33,000................................             2,798               358                56                14                27                40
33,001-96,000...............................               307                28                 2  ................  ................                 2
96,001-500,000..............................                62                 1  ................  ................  ................                 1
500,001-1 M.................................                 4  ................  ................  ................  ................                 1
>1 M........................................                 3  ................  ................  ................  ................  ................

    Total...................................            27,610            12,691             7,191            10,850            20,189            61,937
    Combined Total..........................  ................            40,301  ................            18,041  ................            82,126
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: RTCR Occurrence and Predictive Model Output as detailed in the RTCR EA (USEPA 2012a)

    EPA estimated the numbers of ground water PWSs that monitor
monthly, quarterly, and annually under the 1989 TCR based on an
analysis of the Six-Year Review 2 data and individual State statutes
conducted by EPA and the advisory committee Technical Work Group (TWG).
Of the ground water PWSs serving 1,000 or fewer people, EPA estimated
that approximately 34,000 monitor monthly, 67,000 monitor quarterly,
and 27,000 monitor annually. EPA assumed that the numbers of systems on
monthly, quarterly, and annual monitoring remain unchanged at the rule
effective date for a continuation of the 1989 TCR. For the RTCR option,
EPA assumed that only the percentage of systems that received an annual
site visit under the 1989 TCR would continue on annual monitoring under
the RTCR; the percentage of systems that would therefore no longer
qualify for annual monitoring under the RTCR were assumed to revert to
baseline quarterly monitoring. Under the Alternative option, all PWSs,
regardless of size or type, start at monthly monitoring at the rule
effective date.
    The following two tables provide an overview of summary statistics
relating to baseline water quality. Exhibit VI-5 shows the percentage
of total coliform- and E. coli-positive samples based on PWS type and
size. The percentages of samples that are total coliform-positive are
generally higher in ground water systems than in surface water systems;
in smaller systems than in larger systems; and in NCWSs than in CWSs.

                                    Exhibit VI-5--Total Coliform and E. coli Percent Positive by System Size and Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Total
                                                           Population       coliform      Total        Total        E. coli     E. coli (+   E. coli (%
             PWS Type                  Source water          served        (  coliform (+  coliform (%   (     samples)     positive)
                                                                            samples)     samples)    positive)   samples) \1\                    \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
CWS..............................  Ground Water (GW)..             <=100       93,105        2,479         2.66         1,172           72          0.08
                                   ...................           101-500      125,490        2,500         1.99         1,639           61          0.05
                                   ...................         501-1,000       48,265          736         1.52           483           20          0.04
                                   ...................       1,001-4,100      110,391        1,176         1.07           732           21          0.02
                                   ...................      4,101-33,000      183,721          877         0.48           458           22          0.01
                                   ...................    33,001-100,000       96,361          214         0.22            44            2          0.00
                                   ...................          >100,000       64,965          289         0.44            34            1          0.00
                                   ...................          Total GW      722,298        8,271         1.15         4,562          199          0.03
                                   Surface Water (SW).             <=100        6,735           95         1.41            64            6          0.09
                                   ...................           101-500       19,716          227         1.15           159           10          0.05
                                   ...................         501-1,000       12,828           90         0.70            70            7          0.05
                                   ...................       1,001-4,100       55,310          314         0.57           233           17          0.03
                                   ...................      4,101-33,000      175,758          525         0.30           399           41          0.02
                                   ...................    33,001-100,000      112,894          157         0.14           106            5          0.00
                                   ...................          >100,000      112,143          235         0.21            99            2          0.00
                                   ...................          Total SW      495,384        1,643         0.33         1,130           88          0.02
                                   GW & SW............         Total CWS    1,217,682        9,914         0.81         5,692          287          0.02
TNCWS............................  GW.................             <=100      163,730        7,820         4.78         5,820          316          0.20
                                   ...................           101-500       52,891        2,418         4.57         1,869           99          0.19
                                   ...................         501-1,000        6,952          299         4.30           217            4          0.06
                                   ...................            >1,000        7,062          143         2.02            85            2          0.03
                                   ...................          Total GW      230,635       10,680         4.63         7,991          421          0.18
                                   SW.................             <=100        6,723          150         2.23           141           17          0.25
                                   ...................           101-500        2,854           75         2.63            69           13          0.46
                                   ...................         501-1,000          523           19         3.63            19  ...........          0.00
                                   ...................            >1,000          988            6         0.61            37  ...........          0.00
                                   ...................          Total SW       11,088          250         2.25           266           30          0.27
                                   GW & SW............       Total TNCWS      241,723       10,930         4.52         8,257          451          0.19
NTNCWS...........................  GW.................             <=100       46,505        1,476         3.17         1,061           34          0.07
                                   ...................           101-500       33,084          893         2.70           628           19          0.06
                                   ...................         501-1,000        9,531          166         1.74           103            2          0.02
                                   ...................            >1,000       13,138          177         1.35           103            5          0.04
                                   ...................          Total GW      102,258        2,712         2.65         1,895           60          0.06
                                   SW.................             <=100        1,668           32         1.92            30            4          0.24
                                   ...................           101-500        2,304            9         0.39             9            2          0.09
                                   ...................         501-1,000          932            6         0.64             5  ...........          0.00
                                   ...................            >1,000        1,316            1         0.08             1  ...........          0.00
                                   ...................          Total SW        6,220           48         0.77            45            6          0.10
                                   GW & SW............      Total NTNCWS      108,478        2,760         2.54         1,940           66          0.06
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of samples that were specifically tested for E. coli. The denominator of the E. coli percent positive calculation includes this number plus
  the number of total coliform negative samples (number of total coliform samples--number of total coliform-positive samples).
\2\ Percent of E. coli-positive was calculated as (number of E. coli-positive samples)/(number of E. coli samples taken) x 100.
Source: Derived using Six-Year Review 2 Data, which was filtered by including a State only if the State's PWSs as a group had submitted at least 50
  percent of the expected sample-months of usable data. The Total Coliform Compliance Monitoring Data Quality and Completion Report (USEPA 2010b)
  includes a detailed description of this data cleaning process.

    Exhibit VI-6 presents the number of acute and non-acute violations
reported by PWSs. The number of violations is also an indicator of
baseline water quality prior to implementation of the RTCR. As
discussed in detail chapter 5 of the RTCR EA, EPA used these data to
estimate the numbers of MCL violations and triggers for PWSs serving
more than 4,100 people for the three options. Under the 1989 TCR,
larger systems incur a relatively small number of violations annually,
while smaller systems incur the majority.

                                     Exhibit VI-6--Baseline Number of TCR Violations by System Size and Type (2005)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Ground water PWSs                      Surface Water PWSs
                                                              ------------------------------------------------------------------------------   All PWSs
                                                                Non-Acute      Acute        Total      Non-Acute      Acute        Total        Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
CWSs
--------------------------------------------------------------------------------------------------------------------------------------------------------
<100.........................................................          905           52          957           16            3           19          976
101-500......................................................          809           34          843           50            7           57          900
501-1,000....................................................          203           13          216           16            3           19          235
1,001-3,300..................................................          272            8          280           55            7           62          342
3,301-10,000.................................................          171            8          179           75            3           78          257
10,001-50,000................................................          125            8          133           78            4           82          215
50,001-100,000...............................................           11            2           13            5            4            9           22
100,001-1M...................................................            1            1            2            4            1            5            7
                                                              ------------------------------------------------------------------------------------------
> 1M.........................................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
    Total CWSs...............................................        2,497          126        2,623          299           32          331        2,954
--------------------------------------------------------------------------------------------------------------------------------------------------------
NTNCWSs
--------------------------------------------------------------------------------------------------------------------------------------------------------
<100.........................................................          514           34          548            7            2            9          557
101-500......................................................          346           20          366            4  ...........            4          370
501-1,000....................................................           57            6           63            2  ...........            2           65
1,001-3,300..................................................           58            4           62  ...........  ...........  ...........           62
3,301-10,000.................................................            9            2           11            1  ...........            1           12
10,001-50,000................................................            1  ...........            1  ...........  ...........  ...........            1
50,001-100,000...............................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
100,001-1M...................................................            1  ...........            1  ...........  ...........  ...........            1
> 1M.........................................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
                                                              ------------------------------------------------------------------------------------------
    Total NTNCWSs............................................          985           66        1,051           14            2           16        1,067
--------------------------------------------------------------------------------------------------------------------------------------------------------
TNCWSs
--------------------------------------------------------------------------------------------------------------------------------------------------------
<100.........................................................        2,665          278        2,943           19            5           24        2,967
101-500......................................................          833           76          909           11            1           12          921
501-1,000....................................................          133           11          144            4  ...........            4          148
1,001-3,300..................................................           58            2           60            1  ...........            1           61
3,301-10,000.................................................            5  ...........            5            1  ...........            1            6
10,001-50,000................................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
50,001-100,000...............................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
100,001-1M...................................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
> 1M.........................................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........
                                                              ------------------------------------------------------------------------------------------
    Total TNCWSs.............................................        3,694          367        4,061           36            6           42        4,103
    Grand Total..............................................        7,176          559        7,735          349           40          389        8,124
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The RTCR EA uses violations data for PWSs serving greater than 4,100 people to estimate triggers for these systems. Data for other system sizes is
  provided for reference.
Source: Acute/Non-Acute Violations from SDWIS/FED annual data for period ending 3rd quarter 2001-2007 (only 2005 data is presented in this exhibit). OH,
  U.S. territories, Tribal PWS data excluded. See the RTCR EA (USEPA 2012a) for additional details.

E. Anticipated Benefits of the RTCR

    In promulgating the RTCR, EPA expects to further reduce the risk of
contamination of public drinking water supplies from the current
baseline risk under the 1989 TCR. The options considered during
development of this rule and analyzed as part of the RTCR EA are
designed to achieve this reduction while maintaining public health
protection in a cost-effective manner.
    This section examines the benefits in terms of trade-offs among
compliance with the 1989 TCR option, the RTCR option, and the
Alternative option. Because there are insufficient data reporting the
co-occurrence in a single sample of fecal indicator E. coli and
pathogenic organisms and because the available fecal indicator E. coli
data from the Six-Year Review 2 dataset were limited to presence-
absence data, EPA was unable to quantify health benefits for the RTCR.
EPA used several methods to qualitatively evaluate the benefits of the
RTCR options. The qualitative evaluation uses both the judgment of EPA
as informed by the TCRDSAC deliberations as well as quantitative
estimates of changes in total coliform occurrence and counts of systems
implementing corrective actions. The evaluation characterizes, in
relative terms, the reduction in risk for each regulatory scenario as
compared to baseline conditions.
    Since E. coli is an indicator of fecal contamination, EPA assumed
that a decrease in E. coli occurrence in the

distribution system would be associated with a decrease in fecal
contamination in the distribution system. In general, this decrease in
fecal contamination should reduce the potential risk to human health
for PWS customers. Thus, any reduction in E. coli occurrence is
considered a benefit of the RTCR. Since fecal contamination may contain
waterborne pathogens including bacteria, viruses, and parasitic
protozoa, in general, a reduction in fecal contamination should reduce
the risk from all of these contaminants.
    As presented in Exhibit VI-5, the percentages of samples that are
positive for total coliforms and E. coli are generally higher for PWSs
serving 4,100 or fewer people than those serving more than 4,100
people. PWSs with higher total coliform and E. coli occurrence are more
likely to be triggered into assessments and corrective action. As
discussed previously, the assessments and corrective action lead to a
decrease in total coliform and E. coli occurrence. Because the PWSs
serving 4,100 or fewer people have a higher initial E. coli occurrence
and are likely triggered into more assessments and corrective actions
than larger PWSs, the increase in benefits for these small systems are
likely more evident as compared to the larger systems. In particular,
model results suggest that customers of small ground water TNCWSs
serving 100 or fewer people, which constitute approximately 40 percent
of PWSs, experience the most improvement in water quality under the
RTCR. That is, the occurrence of E. coli is predicted to decrease more
for these systems than for other systems types.
1. Relative Risk Analysis
    When revising an existing drinking water regulation, one of the
main concerns is to ensure that backsliding on water quality and public
health protection does not occur. SDWA requires that EPA maintain or
improve public health protection for any rule revision. The RTCR is
more stringent than the 1989 TCR with regard to protecting public
health. The basis for this perspective is provided in this subsection
and the following subsections (sections VI.E.2, Changes in violation
rates and corrective actions, and VI.E.3, Nonquantifiable benefits) of
this preamble.
    Risk reduction for the RTCR is characterized by the activities
performed that are presumed to reduce risk of exposing the public to
contaminated water. These activities are considered under each rule
component presented in Exhibit VI-8.
    More frequent monitoring has the potential to decrease the risk of
contamination in PWSs based on an enhanced ability to diagnose and
mitigate system issues in a more timely fashion. Conversely, less
frequent monitoring has the potential to increase risk. Real-time
continuous sampling would mitigate the most risk possible based on
sampling schedule; however, it would cost prohibitively more than the
periodic sampling practiced under the 1989 TCR and included in the RTCR
and the Alternative option. EPA's objective in proposing the sampling
schedules included in the RTCR and Alternative option was to find an
appropriate balance between the factors of risk mitigation and cost
management.
    Under the RTCR and Alternative option, the reduction in the number
of required repeat samples and additional routine samples for some PWSs
has the potential to contribute to increased risk for PWS customers
(see also section III.C, Monitoring, and III.D, Repeat Samples, of this
preamble for discussions on the additional routine sample and repeat
sample provisions respectively). However, this potential increase in
risk is expected to be more than offset by potential decreases in risk
from increased routine monitoring (see section III.C of this preamble,
Monitoring) and the addition of the assessments and corrective action
provisions (see section III.E of this preamble, Coliform Treatment
Technique) that find and fix problems indicated by monitoring. Exhibit
VI-7 illustrates the predicted reduced frequency at which total
coliforms occur subsequent to the implementation of the RTCR and
Alternative option. As discussed previously, the RTCR uses total
coliform occurrence as an indicator of potential pathways for possible
contamination to enter the distribution system (see section III.B of
this preamble, Rule Construct: MCLG and MCL for E. coli and Coliform
Treatment Technique). Exhibit VI-7 illustrates the combined effects on
total coliform occurrence resulting from changes in monitoring and the
effects of assessments and corrective actions for the different rule
options for very small systems. The relative trends indicated in
Exhibit VI-7 for TNCWSs also pertain to other PWS categories as
illustrated in chapter 5 of the RTCR EA. EPA chose to include the
characterization for TNCWSs because they represent the system category
of largest influence on the national impacts.

[GRAPHIC] [TIFF OMITTED] TR13FE13.000

    The effect that the elimination of public notification requirements
for monthly/non-acute MCL violations has on risk is difficult to
predict. Some factors, such as reduction in available public
information and possible PWS complacency, lead to a potential increase
in risk and other factors, such as less confusion (PN more in line with
potential health risks) and PWSs resources used more efficiently, lead
to a potential decrease, as discussed in Exhibit VI-8. This change to
PN is addressing a key concern expressed by various stakeholders in the
advisory committee and during the Six-Year Review 1 comment
solicitation process. By eliminating the requirement and replacing it
with assessment and corrective action requirements, the Agency expects
less public confusion, more effective use of resources, increased
transparency, and increased public health protection.
    Other rule components are expected to have a negligible effect on
risk. However, the overall effect of the RTCR is expected to be a
further reduction in risk from the current baseline risk under the 1989
TCR. Chapter 6 of the RTCR EA presents a detailed discussion of the
potential influence on health risk for each rule component.

                         Exhibit VI-8--Potential Changes in Risk Under the RTCR and Alternative Option Relative to the 1989 TCR
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                      Factors leading to a potential          Factors leading to a potential         Overall predicted change in risk
                                             increase in risk                        decrease in risk            ---------------------------------------
         RTCR Component          --------------------------------------------------------------------------------
                                         RTCR             Alternative            RTCR             Alternative            RTCR             Alternative
--------------------------------------------------------------------------------------------------------------------------------------------------------
Implementation Activities.......  None..............  None..............  None..............  None..............  No change.........  No change.

Routine Monitoring (Including     None..............  None..............  Increased           PWSs all monitor    Decrease..........  Decrease.
 Reduced Monitoring).                                                      stringency in       monthly in the
                                                                           requirements to     first few years
                                                                           qualify for         of implementation
                                                                           reduced             of the RTCR,
                                                                           monitoring along    which is an
                                                                           with requirement    increase in
                                                                           to return to        sampling
                                                                           baseline            frequency for
                                                                           monitoring upon     systems that
                                                                           loss of these       monitor quarterly
                                                                           criteria is         or annually under
                                                                           expected to         the 1989 TCR.
                                                                           result in           After the first
                                                                           decreased risk      few years,
                                                                           (That is, fewer     systems may
                                                                           PWSs will qualify   reduce to
                                                                           and therefore       quarterly, but
                                                                           PWSs will on        none may reduce
                                                                           average monitor     to annual
                                                                           more frequently     monitoring,
                                                                           than under the      creating a
                                                                           baseline for        decrease in risk
                                                                           reduced             for systems on
                                                                           monitoring).        annual monitoring
                                                                                under the 1989
                                                                                TCR.
Repeat Monitoring...............  Required repeat     Same as RTCR        None..............  None..............  Increase..........  Increase.
                                   samples reduced     option.
                                   from 4 to 3 for
                                   systems serving
                                   <1,000 people.
Additional Routine Monitoring...  Additional routine  Same as RTCR        None..............  None..............  Increase..........  Increase.
                                   samples are no      option.
                                   longer required
                                   for PWSs
                                   monitoring
                                   monthly..
                                  Ground water PWSs
                                   serving 1,000 or
                                   fewer people
                                   reduce additional
                                   routine samples
                                   from 5 to 3.
Annual Site Visits..............  None (only States   Annual monitoring   None..............  None..............  No change.........  Increase.
                                   currently           is not permitted
                                   performing annual   under the
                                   site visits are     Alternative
                                   expected to         option, so the
                                   continue).          protective
                                                       benefit of the
                                                       annual site visit
                                                       is lost.
Assessments.....................  None..............  None..............  Mandatory           Same as RTCR        Decrease..........  Decrease.
                                                                           assessments are a   option.
                                                                           new requirement.
Corrective Actions..............  None..............  None..............  Mandatory           Same as RTCR        Decrease..........  Decrease.
                                                                           corrective          option.
                                                                           actions are a new
                                                                           requirement.
Public Notification--Monthly/Non- Reduction in        Same as RTCR        Less confusion (PN  Same as RTCR        Unknown...........  Unknown.
 Acute MCL Violations.             available public    option.             more in line with   option.
                                   information.                            potential health
                                  Possible PWS                             risks).
                                   complacency.                           PWSs resources
                                                                           used more
                                                                           efficiently.

Public Notification--Monitoring   None..............  None..............  Increased           Same as RTCR        Decrease..........  Decrease.
 and Reporting Violations.                                                 stringency of PNs   option.
                                                                           motivates PWSs to
                                                                           conduct required
                                                                           sampling.
Overall.........................  ..................  ..................  ..................  ..................  Decrease..........  Decrease.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: Detailed discussion of the rationale for determinations of potential risk for each rule component is presented in chapter 6 (section 6.2) of the
  RTCR EA (USEPA 2012a). Implementation activities consist of administrative activities by PWSs and States to implement the rule.
Assessment of potential changes in risk for monitoring components is an overall assessment. Potential changes (or static state) of risk for particular
  system sizes and types differ according to individual regulatory requirements and are discussed in section 6.2 of the RTCR EA. Chapter 3 of the RTCR
  EA provides a detailed description of the regulatory components for all three regulatory scenarios, and this preamble provides additional discussion
  of the TCRDSAC process and the rationale underlying the structure of the regulatory options considered.

2. Changes in Violation Rates and Corrective Actions
    The quantified portion of the benefits analysis focuses on several
measures that contribute to the changes in risk expected under the
RTCR. Specifically, EPA modeled the predicted outcomes based on each
regulatory option considered--baseline (1989 TCR), the RTCR (final
rule), and the Alternative option--in the form of estimates of non-
acute violations for the 1989 TCR and assessment triggers for the RTCR
and Alternative option; E. coli violations; and the number of
corrective actions implemented under each option. This section of the
preamble includes six graphs (Exhibit VI-9 through Exhibit VI-14) that
help to illustrate these endpoints.
    Evaluation of each of these endpoints informed EPA's understanding
of potential changes to the underlying quality of drinking water. In
particular, the number of corrective actions performed has a strong
relationship to potential improvements in water quality and public
health. For a given rate of total coliform and E. coli occurrence, an
increase in the number of corrective actions implemented leads to
improved water quality. However, a reduction in sampling likely leads
to a reduction in total coliform and E. coli positives being found,
which in turn likely leads to a reduction in assessments and corrective
actions being implemented. The number of total coliform and E. coli
positives that are prevented, missed, or found under each regulatory
option considered in comparison to those predicted under the 1989 TCR
results in estimates of annual non-acute and acute violations (1989
TCR) and assessment triggers (RTCR and Alternative option). Section 6.4
of the RTCR EA presents a step-wise sensitivity analysis of the
competing effects of additional protective activity (e.g., assessments
and corrective actions) and decreased additional routine and repeat
sampling of the RTCR compared to the 1989 TCR. The conclusions of this
sensitivity analysis showed that for all categories of systems, more
total coliform and E. coli positives are expected to be prevented than
missed under the RTCR relative to the 1989 TCR.
    For each of the graphs presented in Exhibit VI-9 through Exhibit
VI-14, there are two main model drivers that affect the endpoints
depicted: the total number of samples taken over time (including
routine, additional routine, and repeat samples) and the effect of
corrective actions taken. When looking at the comparisons between the
1989 TCR with the RTCR across all PWSs, the overall effect of the total
numbers of samples taken is negligible because the total number of
samples predicted to be taken throughout the period of analysis is
almost the same (approximately 82M samples) under both the 1989 TCR and
RTCR. For the Alternative option, the analysis predicts that
approximately 88M total samples are taken over the period of analysis.
Exhibit VI-18 of this preamble presents estimated total numbers of
samples taken over the 25-year period of analysis. Based on the
relationships of total samples taken among the 1989 TCR, RTCR, and
Alternative option, the best way to interpret the graphs presented in
this section is in a step-wise manner.
    The first comparison that should be made is between the 1989 TCR
option and RTCR. Because similar total numbers of samples are taken
under the 1989 TCR and RTCR, the major effect seen in the graphs can be
isolated to the effects that implementation of corrective actions has
on underlying occurrence and how that occurrence influences the
endpoint in question (assessments, E. coli MCL violations, and
corrective actions). In each graph, this is depicted by a marked
reduction in the endpoint under the RTCR compared to the 1989 TCR
option and is a reflection of overall better water quality. The second
comparison can then be made of the Alternative option against the RTCR.
In each graph, the predicted results (assessments, E. coli MCL
violations, and corrective actions) for the Alternative option are
above those for the RTCR and represent an additional benefit over the
RTCR. This additional benefit is primarily a function of the additional
diagnostic abilities gained through increased monitoring under the
Alternative option, and is especially prominent in the early years of
the analysis, since all systems are initially required to monitor at
least monthly.
    More detailed descriptions of each endpoint considered in terms of
the evaluation process described previously are provided in this
section as they apply to the individual graphs in Exhibit VI-9 through
VI-14. Each of the graphs shown in this section is presented first in
nondiscounted terms, and then based on a discount rate of three percent
to reflect the reduced valuation of potential benefits over time,
consistent with the presentation of costs in the section that follows.
Graphs of benefits discounted using seven percent discounted rates are
presented in Appendix B of the RTCR EA.
    Exhibit VI-9 shows the effect (on average across all PWSs) of the
RTCR and the Alternative option on the annual number of non-acute
violations (1989 TCR) and assessment triggers (RTCR and Alternative
option) over time. The estimated reduction of annual assessment
triggers (from the 1989 TCR

estimates of non-acute violations) by approximately 1,000 events under
the RTCR is a reflection of the improved water quality expected under
the RTCR. A similar but smaller reduction in non-acute violations
(Level 1 triggers) from the 1989 TCR is seen under the Alternative
option. The larger initial estimate of assessment triggers followed by
a higher steady state number for the Alternative option than seen under
the RTCR reflects the diagnostic abilities provided by increased
sampling under the Alternative option. The additional triggers
identified by increased sampling under the Alternative option translate
into greater potential benefits than under the RTCR.
    Exhibit VI-10 shows the effect (on average across all PWSs) of the
RTCR and the Alternative option with respect to E. coli violations
found over the 25-year period of analysis in comparison to the 1989
TCR. The overall reduction in annual E. coli violations under the RTCR
of more than 100 events is a measure that should correlate more closely
with expected benefits (that is, reductions in adverse health outcomes)
than non-acute events (as presented in Exhibit VI-9) because E. coli
violations are a direct result of measurement of fecal contamination in
water. A similar but smaller reduction in E. coli violations is seen
under the Alternative option after steady state is achieved. This is
the result of two off-setting effects. The ``true'' number of steady
state violations under the Alternative option is lower because there is
a greater likelihood that violations will be found and fixed. However,
the additional monitoring leads to a higher percentage of violations
being detected. This second effect outweighs the first, so that the
total number of detected violations in the steady state is higher than
for the RTCR, even though the underlying ``true'' number of violations
is lower. This lower number of ``true'' violations means that the
Alternative option is more protective of public health, even though
more violations are detected.
    Exhibit VI-11 presents estimates over the 25-year period of
analysis of the increase in corrective actions relative to the 1989 TCR
(on average across all PWSs) attributable to the RTCR and Alternative
option. Performance of these additional corrective actions is expected
to result in the most direct benefits under the RTCR. Because only the
incremental numbers of corrective actions estimated under the RTCR and
Alternative option were modeled, the reference point for comparison to
the 1989 TCR is the base (zero) line in the graph. The RTCR EA assumes
that corrective actions are already being performed under the 1989 TCR.
Baseline corrective actions are taken into account by assuming only a
modest incremental increase of 10 percent in implementation of
effective corrective actions under both the RTCR and Alternative
option.
    Exhibit VI-11 indicates that more corrective actions are
implemented under the Alternative option than under the RTCR. This is
driven, again, by the increased diagnostic power of more sampling and
reflects additional potential benefits beyond those gained under the
RTCR.
    Taken together, Exhibit VI-9 through Exhibit VI-11 indicate that
the modeled endpoints for the RTCR and the Alternative option predict
positive benefits in comparison to the 1989 TCR; in particular, the
Alternative option captures more benefits than the RTCR. Similar to the
patterns seen in Exhibits VI-9 through VI-11, for each of the
discounted endpoints presented over time in Exhibits VI-12 though VI-
14, the graphs show that (on average across all PWSs) the Alternative
option provides more benefit than the RTCR, and both provide more
benefit than the 1989 TCR. These outcomes are consistent with the
qualitative assessment of the benefits summarized in this section of
this preamble.
    The major difference between the RTCR and the Alternative option is
the increased monitoring that is required under the Alternative option.
The increased diagnostic ability of the extra samples taken under the
Alternative option is seen in the large difference in the endpoint
counts through the first several years in Exhibit VI-9 through Exhibit
VI-14. Absent this effect, the Alternative option essentially mirrors
the RTCR in the exhibits. Even though the predicted results
(assessments, E. coli MCL violations, and corrective actions) under the
Alternative option are greater than the 1989 TCR at first, the trend is
due to initially finding more problems through monitoring. The
increased monitoring during the first several years under the
Alternative option results in a frontloading of benefits at the
beginning of the implementation period. The benefits, however, tend to
even out over time between the RTCR and Alternative option as eligible
systems qualify for less intense (quarterly) monitoring under the
Alternative option. However, the Alternative option leads to a greater
number of assessments, E. coli MCL violations, and corrective actions
than the RTCR because all PWSs are required to sample no less than
quarterly under the Alternative option while under the RTCR qualifying
PWSs are permitted to sample at a minimum of once per year: more
monitoring has the potential for more triggered assessments, corrective
actions, and/or violations than less monitoring.

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BILLING CODE C
3. Nonquantifiable Benefits
    a. Potential decreased incidence of endemic illness from fecal
contamination, waterborne pathogens, and associated outbreaks. As
discussed in section VI.E of this preamble, Anticipated Benefits of the
RTCR, and chapter 2 of the RTCR EA, benefits from the RTCR may include
avoidance of a full range of health effects from the consumption of
fecally contaminated drinking water, including the following: acute and
chronic illness, endemic and epidemic disease, waterborne disease
outbreaks, and death. EPA recognizes that the EPA-approved standard
methods available for E. coli do not typically identify the presence of
the pathogenic E. coli strains, such as E. coli O157:H7. Thus, E. coli
occurrence, as used in this EA, serves as an indication of fecal
contamination but not necessarily pathogenic contamination. See also
discussion in section II.D of this preamble, Public Health Concerns
Addressed by the Revised Total Coliform Rule.
    EPA was unable to quantify the cases of morbidity or mortality
avoided because there are insufficient data reporting the co-occurrence
of fecal indicator E. coli and pathogenic organisms in a single water
sample, and because the available fecal indicator E. coli data from the
Six-Year Review 2 dataset were limited to presence-absence data.
Instead, EPA estimated changes in total coliform and fecal indicator E.
coli occurrence and changes in number of corrective actions as measures
of reduced risk. As discussed previously, the assessments and
corrective actions required under the RTCR will help lead to a decrease
in total coliform and E. coli occurrence in drinking water. Since fecal

contamination can contain waterborne pathogens including bacteria,
viruses, and parasitic protozoa, in general, a reduction in fecal
contamination should reduce the potential risk from all of these
contaminants and the associated primary and secondary endemic disease
burden, both acute and chronic.
    b. Other nonquantifiable benefits. This section describes other
nonquantified benefits, which include those associated with increased
knowledge regarding system operation, accelerated maintenance and
repair, avoided costs of outbreaks, and reductions in averting
behavior.
    By requiring PWSs to conduct assessments that meet minimum elements
focused on identifying sanitary defects in response to triggers for
total coliform- or E. coli-positive samples, the RTCR increases the
likelihood that PWS operators, in particular those of systems triggered
to conduct assessments and corrective action, will develop further
understanding of system operations and improve and practice preventive
maintenance compared to the 1989 TCR, which does not require PWSs to
perform assessments and corrective action.
    Another non-quantified benefit is that systems may choose
corrective actions that also address other drinking water contaminants.
For example, correcting for a pathway of potential contamination into
the distribution system can possibly also mitigate a variety of other
potential contaminants. Due to the lack of data available on the effect
of corrective action on contamination entering through distribution
system pathways, EPA has not quantified such potential benefits.
    Some systems may see additional nonquantified benefits associated
with the acceleration of their capital replacement fund investments in
response to early identification of impending problems with large
capital components. Although such capital investment will eventually
occur in the absence of RTCR requirements, earlier investment may
ensure that problems are addressed in a preventive manner and may
preclude some decrease in protection that might have occurred
otherwise. At the very least, the increased operator awareness is
expected to reduce the occurrence of unplanned capital expenditures in
any given year. However, because of the difficulty of projecting when
capital replacements would occur, EPA has not costed this acceleration
of capital replacement, so there would also be a nonquantified cost of
making such investments sooner.
    Another major non-health benefit is the avoided costs associated
with outbreak response. Outbreaks can be very costly for both the PWS
and the community in which they occur. Avoided outbreak response costs
include such costs as issuing public health warnings, boiling drinking
water and providing alternative supplies, remediation and repair, and
testing and laboratory costs. Reduced total coliform occurrence
resulting from the RTCR may also lead to a reduction of costs
associated with boil-water orders, which some States require following
non-acute violations under the 1989 TCR. Taken together, these expenses
can be quite significant. For example, an analysis of the economic
impacts of a waterborne disease outbreak in Walkerton, Ontario
(population 5,000) estimated the economic impact (excluding estimates
of the value of a statistical life for seven deaths and intangible
costs for illness-related suffering) to be over $45.9M in 2007 Canadian
dollars (approximately $42.8M 2007 US dollars) (Livernois 2002). Note
that some of these costs were incurred by individuals and businesses in
neighboring communities. The author of the study suggested that this
was a conservative estimate.
    In addition, the RTCR may also reduce uncertainty regarding
drinking water safety, which may lead to reduced costs for averting
behaviors. Averting behaviors include the use of bottled water and
point-of-use devices. This benefit also includes the reductions in time
spent on averting behavior such as the time spent obtaining alternative
water supplies.

F. Anticipated Costs of the RTCR

    To understand the net impacts of the RTCR on public water systems
and States in terms of costs, EPA first used available data,
information, and best professional judgment to characterize how PWSs
and States are currently implementing the 1989 TCR. Then, EPA
considered the net change in costs that results from implementing the
RTCR or Alternative option as compared to the costs of continuing with
the 1989 TCR. The objective was to present the net change in costs
resulting from revisions to the 1989 TCR rather than absolute total
costs of implementing the 1989 TCR as revised by the RTCR. More
detailed information on cost estimates is provided in the sections that
follow and a complete discussion can be found in chapter 7 of the RTCR
EA. A detailed discussion of the RTCR requirements is located in
section III of this preamble, Requirements of the Revised Total
Coliform Rule.
1. Total Annualized Present Value Costs
    To compare cost of compliance activities for the three regulatory
scenarios, the year or years in which all costs are expended are
determined and the costs are then calculated as a net present value.
For the purposes of this EA, one-time and yearly costs were projected
over a 25-year time period to allow comparison with other drinking
water regulations using the same analysis period. For this analysis,
the net present values of costs in 2007 dollars are calculated using
discount rates of three percent and seven percent. These present value
costs are then annualized over the 25-year period using the two
discount rates.
    Exhibit VI-15 summarizes the comparison of total and net change in
annualized present value costs of the RTCR and Alternative option
relative to the 1989 TCR baseline. A continuation of the 1989 TCR will
result in no net change in costs. In calculating the 1989 TCR baseline,
not all activities that PWSs and States are performing under the 1989
TCR were quantified (see Exhibit VI-16 of this preamble). Some of these
activities are not required under the 1989 TCR but PWSs are performing
them nonetheless (e.g., corrective actions); or these activities are
required under the 1989 TCR and PWSs and States will continue to
perform them under either the RTCR or Alternative option (e.g.,
revising sample siting plans). Instead of determining the absolute
costs of performing these activities, EPA estimated the net increase in
costs from these activities as a result of implementing either the RTCR
or the Alternative option. The net change in mean annualized national
costs of the RTCR option relative to the 1989 TCR is estimated to be
approximately $14M using either a three percent or seven percent
discount rate. The net change in mean annualized national costs for the
Alternative option relative to the 1989 TCR are estimated to be
approximately $30M using a three percent discount rate and $32M using a
seven percent discount rate.
    Under the RTCR, public water systems are estimated to incur greater
than 90 percent of the RTCR's net annualized costs. States are expected
to incur the remaining costs.

                                   Exhibit VI-15--Comparison of Total and Net Change From 1989 TCR in Annualized Costs
                                                                   [$Millions, 2007$]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         3% discount rate                                7% discount rate
                                                         -----------------------------------------------------------------------------------------------
                                                               PWSs            State           Total           PWSs            State           Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR: Baseline \1\..................................             185             0.9             186             178             0.9             179
RTCR: Baseline + Incremental \2\........................             199             1.1             200             192             1.3             193
RTCR: Net Change........................................              14             0.1              14              14             0.4              14
RTCR: Percent Change....................................              8%             16%              8%              8%             48%              8%
Alternative option: Baseline + Incremental \2\..........             214             1.2             216             209             1.5             210
Alternative option: Net Change..........................              29             0.3              30              31             0.6              32
Alternative option: Percent Change......................             16%             34%             16%             17%             69%             18%
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Detail may not add due to independent rounding.
Source: RTCR EA (USEPA 2012a).
\1\ Does not quantify all 1989 TCR components.
\2\ For components not quantified for the 1989 TCR, only the net increase in the costs of these components is considered for the RTCR and Alternative
  option (e.g., corrective action costs).

    Exhibit VI-16 presents the comparison of total and net change in
annualized costs for PWSs and States by rule component. The table shows
that corrective action costs are the most significant contributors to
the net increase in costs for PWSs under the RTCR. For the Alternative
option, routine monitoring costs are the most significant contributor
to the net increase in costs for PWSs. For States, revision of sample
siting plans contributes most to the cost increase under the RTCR and
Alternative option. For both PWSs and States, a net decrease in costs
associated with PN requirements helps to offset the total net cost
increase.

                                 Exhibit VI-16--Comparison of Total and Net Change in Annualized Costs by Rule Component
                                                                   [$Millions, 2007$]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         3% discount rate                                7% discount rate
                                                         -----------------------------------------------------------------------------------------------
                                                               PWSs            State           Total           PWSs            State           Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Rule Implementation and Annual Administration
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Total.............................................            2.77            0.18            2.95            4.00            0.26            4.26
RTCR--Net Change........................................            2.77            0.18            2.95            4.00            0.26            4.26
Alternative Option--Total...............................            2.77            0.18            2.95            4.00            0.26            4.26
Alternative Option--Net Change..........................            2.77            0.18            2.95            4.00            0.26            4.26
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Sample Siting Plan Revision
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Total.............................................            0.59            0.42            1.01            0.84            0.59            1.42
RTCR--Net Change........................................            0.59            0.42            1.01            0.84            0.59            1.42
Alternative Option--Total...............................            0.59            0.42            1.01            0.84            0.59            1.42
Alternative Option--Net Change..........................            0.59            0.42            1.01            0.84            0.59            1.42
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Routine Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................          170.59  ..............          170.59          163.94  ..............          163.94
RTCR--Total.............................................          174.71  ..............          174.71          167.74  ..............          167.74
RTCR--Net Change........................................            4.12  ..............            4.12            3.80  ..............            3.80
Alternative Option--Total...............................          187.50  ..............          187.50          182.48  ..............          182.48
Alternative Option--Net Change..........................           16.91  ..............           16.91           18.54  ..............           18.54
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Additional Routine Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................            3.87  ..............            3.87            3.72  ..............            3.72
RTCR--Total.............................................            1.12  ..............            1.12            1.09  ..............            1.09
RTCR--Net Change........................................          (2.75)  ..............          (2.75)          (2.63)  ..............          (2.63)
Alternative Option--Total...............................            0.78  ..............            0.78            0.66  ..............            0.66
Alternative Option--Net Change..........................          (3.10)  ..............          (3.10)          (3.06)  ..............          (3.06)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Repeat Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................            5.11  ..............            5.11            4.92  ..............            4.92
RTCR--Total.............................................            4.88  ..............            4.88            4.70  ..............            4.70
RTCR--Net Change........................................          (0.23)  ..............          (0.23)          (0.22)  ..............          (0.22)
Alternative Option--Total...............................            5.66  ..............            5.66            5.59  ..............            5.59

Alternative Option--Net Change..........................            0.54  ..............            0.54            0.67  ..............            0.67
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Annual Site Visits
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Total.............................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Net Change........................................  ..............  ..............  ..............  ..............  ..............  ..............
Alternative Option--Total...............................  ..............  ..............  ..............  ..............  ..............  ..............
Alternative Option--Net Change..........................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Level 1 Assessment
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................            1.13            0.21            1.34            1.08            0.20            1.29
RTCR--Total.............................................            1.63            0.20            1.84            1.57            0.20            1.77
RTCR--Net Change........................................            0.51          (0.01)            0.50            0.49          (0.01)            0.48
Alternative Option--Total...............................            1.76            0.23            1.99            1.72            0.23            1.94
Alternative Option--Net Change..........................            0.63            0.02            0.65            0.63            0.02            0.65
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Level 2 Assessment
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................            0.70            0.26            0.96            0.68            0.25            0.92
RTCR--Total.............................................            0.90            0.19            1.08            0.88            0.18            1.06
RTCR--Net Change........................................            0.20          (0.07)            0.12            0.20          (0.07)            0.13
Alternative Option--Total...............................            1.26            0.29            1.55            1.30            0.31            1.61
Alternative Option--Net Change..........................            0.55            0.03            0.58            0.62            0.06            0.68
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Corrective Actions Based on Level 1 Assessments
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Total.............................................            9.62            0.01            9.63            8.14            0.01            8.15
RTCR--Net Change........................................            9.62            0.01            9.63            8.14            0.01            8.15
Alternative Option--Total...............................           10.01            0.01           10.02            8.52            0.01            8.53
Alternative Option--Net Change..........................           10.01            0.01           10.02            8.52            0.01            8.53
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Corrective Actions Based on Level 2 Assessments
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................  ..............  ..............  ..............  ..............  ..............  ..............
RTCR--Total.............................................            2.82            0.00            2.82            2.49            0.00            2.49
RTCR--Net Change........................................            2.82            0.00            2.82            2.49            0.00            2.49
Alternative Option--Total...............................            3.78            0.01            3.79            3.57            0.01            3.58
Alternative Option--Net Change..........................            3.78            0.01            3.79            3.57            0.01            3.58
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Public Notification
--------------------------------------------------------------------------------------------------------------------------------------------------------
1989 TCR--Total.........................................            3.75            0.44            4.19            3.60            0.42            4.02
RTCR--Total.............................................            0.26            0.06            0.32            0.25            0.06            0.31
RTCR--Net Change........................................          (3.49)          (0.38)          (3.86)          (3.35)          (0.36)          (3.71)
Alternative Option--Total...............................            0.35            0.08            0.43            0.35            0.08            0.44
Alternative Option--Net Change..........................          (3.40)          (0.36)          (3.76)          (3.25)          (0.34)          (3.58)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Detail may not add due to independent rounding.
Assumes a certain level of assessment activity already occurs under the 1989 TCR, as discussed in Chapter 7 of the RTCR EA (USEPA 2012a).
Not all 1989 TCR components are quantified. For components not quantified for the 1989 TCR, only the net increase in the costs of these components is
  considered for the RTCR and Alternative option (e.g., corrective action costs).
Source: RTCR EA (USEPA 2012a).

2. PWS Costs
    Like the 1989 TCR, the RTCR applies to all PWSs. Exhibit VI-17
presents the total and net change in annualized costs to PWSs by size
and type for the three regulatory options. No net change in costs will
result from a continuation of the 1989 TCR. Among PWSs serving 4,100 or
fewer people, looking at the three percent discount rate, the largest
increase in aggregate net costs is incurred by the TNCWSs serving 100
or fewer people under either the RTCR ($5.3M) or Alternative option
($14.7M) because of the large number of systems. On a per system basis,
this translates to a net annualized present value increase of
approximately $86 per system under the RTCR and $240 per system under
the Alternative option for the TNCWSs serving 100 or fewer people. As
described in section VII.C of this preamble, Regulatory Flexibility Act
(RFA), none of the small TNCWSs are estimated to have costs that are
greater than or equal to three percent of their revenue and only 61
small systems (0.04%) are estimated to have costs greater than or equal
to one percent of their revenue.
    The total net change in national annualized present value costs for
all

PWSs serving greater than 4,100 people (approximately $5.6M using three
percent discount rate) is the same under the RTCR and Alternative
option. This is expected because the provisions for PWSs serving
greater than 4,100 are the same under the RTCR and the Alternative
option. Monitoring requirements for PWSs serving greater than 4,100
people remain essentially unchanged under either the RTCR or
Alternative option. The observed overall net increase in costs for PWSs
serving greater than 4,100 people is driven primarily by the
requirements to conduct assessments and to correct any sanitary defects
that are found.

                                  Exhibit VI-17--Total and Net Change in Annualized Costs to PWSs by PWS Size and Type
                                                                   [$Millions, 2007$]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         3% discount rate                                           7% discount rate
                                   ---------------------------------------------------------------------------------------------------------------------
   PWS Size (population served)       1989                          Alternative                  1989                          Alternative
                                      TCR      RTCR     RTCR Net       option     Alternative    TCR      RTCR     RTCR net       option     Alternative
                                     Total    Total                    total      option net    total    total                    total      option net
                                          A        B     C = B - A           D      E = D - A        F        G     H = G - F           I      J = I - F
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Community Water Systems (CWSs)
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100.............................      7.4      7.5           0.1         7.6            0.2      7.1      7.3           0.2         7.5            0.3
101-500...........................      9.0      9.4           0.4         9.5            0.5      8.6      9.1           0.5         9.2            0.6
501-1,000.........................      3.7      3.8           0.0         3.8            0.1      3.6      3.7           0.1         3.7            0.1
1,001-4,100.......................     13.2     13.6           0.4        13.6            0.4     12.7     13.1           0.4        13.1            0.4
4,101-33K.........................     42.4     44.8           2.4        44.8            2.4     40.7     42.8           2.1        42.8            2.1
33,001-96K........................     34.9     36.4           1.5        36.4            1.5     33.5     34.8           1.3        34.8            1.3
96,001-500K.......................     34.7     36.2           1.5        36.2            1.5     33.4     34.6           1.2        34.6            1.2
500,001-1M........................      6.5      6.7           0.2         6.7            0.2      6.2      6.4           0.1         6.4            0.1
>1M...............................      5.6      5.6         (0.0)         5.6          (0.0)      5.3      5.3         (0.0)         5.3          (0.0)
                                   ---------------------------------------------------------------------------------------------------------------------
    Total.........................    157.4    163.9           6.5       164.1            6.7    151.3    157.2           5.9       157.5            6.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Nontransient Noncommunity Water Systems (NTNCWSs)
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100.............................      2.6      2.7           0.1         3.7            1.1      2.5      2.7           0.2         3.8            1.4
101-500...........................      1.9      2.0           0.1         2.8            0.9      1.8      2.0           0.2         2.9            1.1
501-1,000.........................      0.6      0.6           0.1         0.9            0.3      0.6      0.6           0.1         0.9            0.3
1,001-4,100.......................      1.2      1.3           0.1         1.3            0.1      1.1      1.2           0.1         1.2            0.1
4,101-33K.........................      0.4      0.5           0.1         0.5            0.1      0.4      0.5           0.0         0.5            0.0
33,001-96K........................      0.1      0.1           0.0         0.1            0.0      0.1      0.1           0.0         0.1            0.0
96,001-500K.......................      0.1      0.1         (0.0)         0.1          (0.0)      0.1      0.1         (0.0)         0.1          (0.0)
500,001-1M........................      0.0      0.0           0.0         0.0            0.0      0.0      0.0           0.0         0.0            0.0
>1M...............................      0.0      0.0           0.0         0.0            0.0      0.0      0.0           0.0         0.0            0.0
                                   ---------------------------------------------------------------------------------------------------------------------
    Total.........................      6.9      7.3           0.4         9.3            2.5      6.6      7.2           0.6         9.6            3.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Transient Noncommunity Water Systems(TNCWSs)
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100.............................     13.4     18.7           5.3        28.1           14.7     12.8     18.2           5.3        28.9           16.1
101-500...........................      4.9      6.5           1.6         9.5            4.7      4.7      6.3           1.6         9.8            5.1
501-1,000.........................      0.6      0.8           0.2         1.2            0.5      0.6      0.8           0.2         1.2            0.6
1,001-4,100.......................      0.9      1.0           0.1         1.0            0.1      0.9      1.0           0.1         1.0            0.1
4,101-33K.........................      0.4      0.5           0.1         0.5            0.1      0.4      0.5           0.0         0.5            0.0
33,001-96K........................      0.1      0.1         (0.0)         0.1          (0.0)      0.1      0.1         (0.0)         0.1          (0.0)
96,001-500K.......................      0.1      0.1         (0.0)         0.1          (0.0)      0.1      0.1         (0.0)         0.1          (0.0)
500,001-1M........................      0.2      0.2         (0.0)         0.2          (0.0)      0.2      0.2         (0.0)         0.2          (0.0)
>1M...............................      0.3      0.3           0.0         0.3            0.0      0.3      0.3           0.0         0.3            0.0
                                   ---------------------------------------------------------------------------------------------------------------------
    Total.........................     20.9     28.1           7.3        41.0           20.1     20.1     27.3           7.3        42.0           21.9
                                   ---------------------------------------------------------------------------------------------------------------------
        Grand Total...............    185.2    199.3          14.2       214.4           29.3    177.9    191.7          13.8       209.0           31.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Detail may not add due to independent rounding. Because only the incremental costs of some rule components are considered as part of the cost
  analysis, references to ``total'' costs in this exhibit do not refer to complete costs for regulatory implementation but only to specific costs
  considered to calculate net change in costs.
Source: RTCR cost model.

    The following subsections discuss the different components of the
costs to PWSs: Rule implementation and annual administration, sample
siting plan revision, monitoring, annual site visits, assessments,
corrective actions, and public notification.
    a. Rule implementation and annual administration. Under the RTCR
and Alternative option, all PWSs subject to the RTCR incur one-time
costs that include time for staff to read the RTCR, become familiar
with its provisions, and to train employees on rule requirements. No
additional implementation burden or costs will be incurred by PWSs if
the 1989 TCR option is maintained. Under the RTCR and Alternative
option, all PWSs subject to the RTCR perform additional or transitional
implementation activities. Based on previous experience with rule
implementation, EPA estimated that

PWSs require a total of four hours to read and understand the rule, and
a total of eight hours to plan and assign appropriate personnel and
resources to carry out rule activities. EPA estimated a net increase in
national annualized cost estimates incurred by PWSs for rule
implementation and annual administration of $2.77M (three percent
discount rate) and $4.00M (seven percent discount rate) under either
the RTCR or the Alternative option. The annualized net present value
total and net change cost estimates for PWSs for rule implementation
and annual administration under the 1989 TCR, RTCR, and Alternative
option are presented in Exhibit VI-16 of this preamble.
    b. Sample siting plan revision. Under the RTCR and Alternative
option, all PWSs subject to the RTCR incur one-time costs to revise
existing sample siting plans to identify sampling locations and
collection schedules that are representative of water throughout the
distribution system. Under the 1989 TCR, no additional burden or costs
are expected to be incurred by PWSs to revise sample siting plans, as
these PWSs are already collecting total coliform samples in accordance
with a written sample siting plan. Based on previous experience, EPA
estimated that PWSs require two to eight hours to revise their sample
siting plan, depending on PWS size. EPA estimated a net increase in
national annualized cost estimates incurred by PWSs for revising sample
siting plans of $0.59M (three percent discount rate) and $0.84M (seven
percent discount rate) under either the RTCR or the Alternative option.
The annualized net present value total and net change cost estimates
for PWSs to revise their sample siting plan under the 1989 TCR, RTCR,
and Alternative option are presented in Exhibit VI-16 of this preamble.
    c. Monitoring. Monitoring costs for PWSs are calculated by
multiplying the total numbers of routine, additional routine, and
repeat samples required under the 1989 TCR, RTCR, and Alternative
options by the monitoring costs per sample. Under the RTCR, the
increased stringency to qualify for reduced monitoring results in more
routine samples being taken over time (fewer PWSs are on reduced
monitoring) compared to the 1989 TCR. For the Alternative option, this
effect is combined with the requirement that all PWSs start the
implementation period on monthly monitoring. The Alternative option
also prohibits annual monitoring, resulting in a greater increase in
the number of routine samples compared to the RTCR. Costs for routine
monitoring under the RTCR and Alternative option are higher than
routine monitoring costs under the 1989 TCR.
    The overall reductions in the numbers of additional routine samples
required under the RTCR and Alternative option result in lower costs
for additional routine monitoring when compared to the 1989 TCR. Under
the RTCR and Alternative option, additional routine monitoring is no
longer required for systems that monitor at least monthly, and when
additional routine monitoring is required, the number of samples
required is reduced from five to three. Cost reductions are greater
under the Alternative option than under the RTCR because under the
Alternative option all PWSs start on monthly monitoring and are not
required to take additional routine samples during that period.
    Costs for repeat sampling are also lower under the RTCR and
Alternative option. Under the 1989 TCR, PWSs serving 1,000 or fewer
people take four repeat samples, at and within five service connections
upstream and downstream of the initial total coliform positive
occurrence location, over the course of 24 hours following the event.
Under the RTCR and Alternative option, PWSs serving 1,000 or fewer
people will need to take only three repeat samples, and they have
greater flexibility about where to take them, consistent with the
system sample siting plan that is developed in accordance with RTCR
requirements and subject to review and revision by the State. The
number of repeat samples required for PWSs serving more than 1,000
people is the same under the 1989 TCR and the RTCR and Alternative
option, although these systems also have greater flexibility in sample
location.
    Exhibit VI-18 summarizes the cumulative number of samples taken by
PWS size and category for routine, additional, and repeat monitoring
under the 1989 TCR, RTCR, and Alternative option over the entire 25-
year period of analysis. Under the 1989 TCR option, approximately 82.1M
samples are taken over the 25-year period of analysis compared to
approximately 82.2M samples under the RTCR and approximately 87.9M
samples under the Alternative option (less than 10 percent more than
1989 TCR option). Appendix A of the RTCR EA presents additional
information on the number of samples taken each year during the
analysis period.

             Exhibit VI-18--Cumulative Number of Samples over 25-Year Period of Analysis for Baseline (1989 TCR) and Regulatory Alternatives
                                                              [RTCR and Alternative option]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    1989 TCR                                 RTCR                               Alternative
                                    --------------------------------------------------------------------------------------------------------------------
                                                   Additional                             Additional                             Additional
    PWS Size (population served)       Routine      routine       Repeat      Routine      routine       Repeat      Routine      routine       Repeat
                                      monitoring   monitoring   monitoring   monitoring   monitoring   monitoring   monitoring   monitoring   monitoring
                                       samples      samples      samples      samples      samples      samples      samples      samples      samples
                                               A            B            C            D            E            F            G            H            I
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Community Water Systems (CWSs)--Surface Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................      304,247       23,167       18,698      308,880  ...........       13,764      308,880  ...........       13,764
101-500............................      562,198       27,009       21,684      567,600  ...........       15,660      567,600  ...........       15,660
501-1,000..........................      306,605       15,334       12,299      309,672  ...........        8,708      309,672  ...........        8,708
1,001-4,100........................    1,921,237       55,132       33,729    1,951,224  ...........       33,326    1,951,224  ...........       33,326
4,101-33K..........................   10,636,296  ...........      186,729   10,636,296  ...........      181,661   10,636,296  ...........      181,661
33,001-96K.........................   11,058,960  ...........      194,149   11,058,960  ...........      188,880   11,058,960  ...........      188,880
96,001-500K........................   10,190,400  ...........      178,901   10,190,400  ...........      174,046   10,190,400  ...........      174,046
500,001-1M.........................    2,019,600  ...........       35,456    2,019,600  ...........       34,493    2,019,600  ...........       34,493
>1M................................    1,686,960  ...........       29,616    1,686,960  ...........       28,812    1,686,960  ...........       28,812
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................   38,686,502      120,642      711,259   38,729,592  ...........      679,350   38,729,592  ...........      679,350
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                      Community Water Systems (CWSs)--Ground Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................    2,815,951      286,073      194,462    2,870,075        8,760      156,897    2,908,469        7,545      158,439
101-500............................    3,344,578      243,895      171,252    3,391,200        6,127      136,906    3,428,876        5,264      137,959
501-1,000..........................    1,072,202       70,803       51,673    1,085,730        1,844       39,659    1,098,488        1,616       39,580
1,001-4,100........................    3,997,293      160,710      100,618    4,079,328  ...........       96,939    4,079,328  ...........       96,939
4,101-33K..........................    9,145,224  ...........      230,201    9,145,224  ...........      217,321    9,145,224  ...........      217,321
33,001-96K.........................    4,884,000  ...........      122,938    4,884,000  ...........      116,060    4,884,000  ...........      116,060
96,001-500K........................    1,945,680  ...........       48,976    1,945,680  ...........       46,236    1,945,680  ...........       46,236
500,001-1M.........................      253,440  ...........        6,380      253,440  ...........        6,023      253,440  ...........        6,023
>1M................................      269,280  ...........        6,778      269,280  ...........        6,399      269,280  ...........        6,399
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................   27,727,648      761,481      933,279   27,923,956       16,731      822,439   28,012,784       14,425      824,956
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Nontransient Noncommunity Water Systems (NTNCWSs)--Surface Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................       65,018        4,910        3,991       66,000  ...........        3,040       66,000  ...........        3,040
101-500............................       66,045        3,735        3,011       66,792  ...........        2,169       66,792  ...........        2,169
501-1,000..........................       22,976        1,278        1,029       23,232  ...........          756       23,232  ...........          756
1,001-4,100........................       41,759        2,142        1,348       42,768  ...........        1,228       42,768  ...........        1,228
4,101-33K..........................       50,424  ...........        1,628       50,424  ...........        1,448       50,424  ...........        1,448
33,001-96K.........................       34,320  ...........        1,108       34,320  ...........          985       34,320  ...........          985
96,001-500K........................       31,680  ...........        1,023       31,680  ...........          910       31,680  ...........          910
500,001-1M.........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
>1M................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................      312,223       12,065       13,138      315,216  ...........       10,536      315,216  ...........       10,536
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Nontransient Noncommunity Water Systems (NTNCWSs)--Ground Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................      971,538      128,775       84,992      932,025       48,142       68,123    1,314,175       36,965       91,416
101-500............................      725,785       66,525       43,597      678,688       25,630       35,860      976,627       19,382       48,269
501-1,000..........................      190,649       16,037       10,680      180,145        6,166        8,601      249,760        4,802       11,817
1,001-4,100........................      460,470       28,214       17,790      473,352  ...........       15,887      473,352  ...........       15,887
4,101-33K..........................      153,648  ...........        5,936      153,648  ...........        5,157      153,648  ...........        5,157
33,001-96K.........................       23,760  ...........          918       23,760  ...........          797       23,760  ...........          797
96,001-500K........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
500,001-1M.........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
>1M................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................    2,525,850      239,551      163,913    2,441,617       79,938      134,426    3,191,322       61,149      173,343
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Transient Noncommunity Water Systems (TNCWSs)--Surface Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................      345,401       40,475       33,065      353,496  ...........       23,122      353,496  ...........       23,122
101-500............................      128,156       15,261       12,454      131,208  ...........        8,192      131,208  ...........        8,192
501-1,000..........................       22,691        2,704        2,207       23,232  ...........        1,533       23,232  ...........        1,533
1,001-4,100........................       40,151        4,155        2,707       42,240  ...........        2,312       42,240  ...........        2,312
4,101-33K..........................       40,656  ...........  ...........       40,656  ...........        2,225       40,656  ...........        2,225
33,001-96K.........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
96,001-500K........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
500,001-1M.........................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
>1M................................      102,960  ...........  ...........      102,960  ...........        5,636      102,960  ...........        5,636
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................      680,015       62,596       50,434      693,792  ...........       43,020      693,792  ...........       43,020
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Transient Noncommunity Water Systems (TNCWSs)--Ground Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=100..............................    4,493,808      905,554      600,315    6,076,163      446,166      631,105    9,524,123      333,524      912,589
101-500............................    1,614,924      316,238      210,714    1,940,946      135,822      194,697    3,021,771      104,732      282,740
501-1,000..........................      177,264       32,730       22,064      206,130       14,078       20,078      304,534       10,412       27,932
1,001-4,100........................      335,283       29,957       19,113      348,480  ...........       16,027      348,480  ...........       16,027
4,101-33K..........................      156,288  ...........        8,909      156,288  ...........        7,188      156,288  ...........        7,188
33,001-96K.........................       34,320  ...........        1,956       34,320  ...........        1,578       34,320  ...........        1,578
96,001-500K........................       26,400  ...........        1,505       26,400  ...........        1,214       26,400  ...........        1,214
500,001-1M.........................       63,360  ...........        3,612       63,360  ...........        2,914       63,360  ...........        2,914
>1M................................  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
                                    --------------------------------------------------------------------------------------------------------------------
    Total..........................    6,901,647    1,284,478      868,188    8,852,088      596,065      874,801   13,479,275      448,667    1,252,181
                                    --------------------------------------------------------------------------------------------------------------------
        Grand Total................   76,833,885    2,480,814    2,740,210   78,956,260      692,734    2,564,572   84,421,981      524,241    2,983,387
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: (B), (E), (H) For modeling purposed, additional routine sample counts include regular routine samples taken in the same month.
Source: Appendix A of the RTCR EA (USEPA 2012a)--Total PWS Counts (A.1z, A.2z, A.3z).

    The annualized total and net change cost estimates for PWSs to
perform monitoring under the 1989 TCR, RTCR, and Alternative option are
presented in Exhibit VI-19. EPA estimated a net increase in national
annualized cost estimates incurred by PWSs for monitoring of $1.14M
(three percent discount rate) and $0.95M (seven percent discount rate)
under the RTCR and a net increase of $14.36M (three percent discount
rate) and $16.15M (seven percent discount rate) under the Alternative
option. See also Exhibit VI-16 of this preamble for a breakdown on the
costs of monitoring (i.e., routine, additional routine, repeat).

    Exhibit VI-19--Annualized National PWS Monitoring Cost Estimates
                           [$Millions, 2007$]
------------------------------------------------------------------------
                                3% discount rate      7% discount rate
------------------------------------------------------------------------
1989 TCR--Total.............               $179.57               $172.57
RTCR--Total.................               $180.71               $173.52
RTCR--Net Change............                 $1.14                 $0.95
RTCR--Percent Change........                 0.63%                 0.55%
Alternative option--Total...               $193.93               $188.72
Alternative option--Net                     $14.36                $16.15
 Change.....................
Alternative option--Percent                  7.99%                 9.36%
 Change.....................
------------------------------------------------------------------------
Note: Detail may not add due to independent rounding.
Source: RTCR EA (USEPA 2012a).

    The overall estimated increase in monitoring costs seen under the
RTCR is driven by increases in routine monitoring due to stricter
requirements to qualify for reduced monitoring. However, this is mostly
offset by reductions in additional routine and repeat monitoring. For
the Alternative option, the requirement for all PWSs to sample on a
monthly basis at the beginning of rule implementation results in a much
larger cost differential that is only partially offset by reduced costs
from reductions in additional routine monitoring requirements.
    d. Annual site visits. Under the RTCR, any PWS on an annual
monitoring schedule is required to also have an annual site visit
conducted by the State or State-designated third party. A voluntary
Level 2 site assessment can also satisfy the annual site visit
requirement. For years in which the State performs a sanitary survey
(at least every five years for NCWSs and three years for CWSs), a
sanitary survey performed during the same year can also be used to
satisfy this requirement. Although similar site visits are not
currently required under the 1989 TCR, discussions with States during
the TCRDSAC proceedings revealed that some do, in fact, conduct such
site visits for PWSs on annual monitoring schedules. Because of the
high cost for an annual site visit by a State, for this analysis EPA
assumed that no States choose to conduct annual site visits unless they
already do so under the 1989 TCR. Therefore, for overall costing
purposes, no net change in PWS or State costs are assumed for annual
monitoring site visits under the RTCR or Alternative option.
    e. Assessments. Annualized cost estimates for Level 1 and Level 2
assessments under the 1989 TCR, RTCR, and Alternative option are
calculated in the RTCR EA by multiplying the number of assessments
estimated by the predictive modeling (summarized in Exhibit 7.13 of the
EA) by the unit costs (summarized in Exhibits 7-11 and 7-12 of the EA).
Appendix A of the RTCR EA provides a detailed breakout of the number of
Level 1 and Level 2 assessments estimated by the occurrence model. EPA
estimated a net increase in national annualized cost estimates incurred
by PWSs for conducting assessment of $0.70M (three percent discount
rate) and $0.69M (seven percent discount rate) under the RTCR and a net
increase of $1.18M (three percent discount rate) and $1.25M (seven
percent discount rate) under the Alternative option. Annualized cost
estimates are presented in Exhibit VI-16 of this preamble.
    Under the RTCR, all PWSs are required to conduct assessments of
their systems when they exceed Level 1 or Level 2 treatment technique
triggers. While PWSs are not required to conduct assessments under the