MPN 2 3 4, multiple tube...........  ......................  9221B.1/9221F 5 6 7...
Multiple tube/multiple well........  ......................  9223B 5 8.............  .....................  991.15 9.............  Colilert[supreg] 8
                                                                                10, Colilert-
                                                                                18[supreg] 8 10 11.
MF 2 3 12 13 14 two step, or.......  1103.1 16.............  9222B/9222G5 15 9213D   D5392-93 17..........
                                                              5.
Single step........................  1603 18, 1604 19......  ......................  .....................  .....................  mColiBlue 24 20.
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 Recommended for enumeration of E. coli in ambient water only, number per 100 ml.
2 Tests must be conducted to provide organism enumeration (density). Select the appropriate configuration of tubes/filtrations and dilutions/volumes to
  account for the quality, character, consistency, and anticipated organism density of the water sample.
3 To assess the comparability of results obtained with individual methods, it is suggested that side-by-side tests be conducted across seasons of the
  year with the water samples routinely tested in accordance with the most current Standard Methods for the Examination of Water and Wastewater or EPA
  alternate test procedure (ATP) guidelines.
4 Samples shall be enumerated by the multiple-tube or multiple-well procedure. Using multiple-tube procedures, employ an appropriate tube and dilution
  configuration of the sample as needed and report the Most Probable Number (MPN). Samples tested with Colilert[supreg] may be enumerated with the
  multiple-well procedures, Quanti-tray[supreg], or Quanti-tray[supreg] 2000, and the MPN calculated from the table provided by the manufacturer.
5 APHA. 1998, 1995, 1992. Standard Methods for the Examination of Water and Wastewater. American Public Health Association. 20th, 19th, and 18th
  Editions. Amer. Publ. Hlth. Assoc., Washington, DC.
6 The multiple-tube fermentation test is used in 9221.B.1. Lactose broth may be used in lieu of lauryl tryptose broth (LTB), if at least 25 parallel
  tests are conducted between this broth and LTB using the water samples normally tested, and this comparison demonstrates that the false-positive rate
  and false-negative rate for total coliform using lactose broth is less than 10 percent. No requirement exists to run the completed phase on 10 percent
  of all total coliform-positive tubes on a seasonal basis.
7 After prior enrichment in a presumptive medium for total coliform using 9221B.1, all presumptive tubes or bottles showing any amount of gas, growth or
  acidity within 48 3 h of incubation shall be submitted to 9221F. Commercially available EC-MUG media or EC media supplemented in the
  laboratory with 50 [mu]g/ml of MUG may be used.
8 These tests are collectively known as defined enzyme substrate tests, where, for example, a substrate is used to detect the enzyme glucuronidase
  produced by E. coli.
9 AOAC. 1995. Official Methods of Analysis of AOAC International, 16th Edition, Volume 1, Chapter 17. Association of Official Analytical Chemists
  International. 481 North Frederick Avenue, Suite 500, Gaithersburg, Maryland 20877-2417.
10 Descriptions of the Colilert[supreg], Colilert-18[supreg], Quanti-Tray[supreg] and Quanti-Tray[supreg] 2000 may be obtained from IDEXX Laboratories,
  Inc., One IDEXX Drive, Westbrook, Maine 04092.
11 Colilert-18[supreg] is an optimized formulation of the Colilert[supreg] for the determination of total coliforms and E. coli that provides results
  within 18 h of incubation at 35 [deg]C rather than the 24 h required for the Colilert[supreg] test and is recommended for marine samples.
12 A 0.45 [mu]m membrane filter (MF) or other pore size certified by the manufacturer to fully retain organisms to be cultivated and to be free of
  extractables which could interfere with their growth.
13 Because the MF technique usually yields low and variable recovery from chlorinated wastewaters, the Most Probable Number method will be required to
  resolve any controversies.
14 When the MF method has not been used previously to test ambient water with high turbidity, large number of noncoliform bacteria, or samples that may
  contain organisms stressed by chlorine, a parallel test should be conducted with a multiple-tube technique to demonstrate applicability and
  comparability of results.
15 Subject total coliform positive samples as determined by 9222B or other membrane filter procedure to 9222G using NA-MUG media.
16 USEPA. 2002c. Method 1103.1: Escherichia coli (E. coli) In Water By Membrane Filtration Using membrane-Thermotolerant Escherichia coli Agar (mTEC).
  U.S. Environmental Protection Agency, Office of Water, Washington, DC. EPA-821-R-02-020.
17 ASTM. 2000, 1999, 1996. Annual Book of ASTM Standards--Water and Environmental Technology. Section 11.02. American Society for Testing and Materials.
  100 Barr Harbor Drive, West Conshohocken, PA 19428.

18 USEPA. 2002. Method 1610: Escherichia coli (E. coli) In Water By Membrane Filtration Using Modified membrane-Thermotolerant Escherichia coli Agar
  (modified mTEC). U.S. Environmental Protection Agency, Office of Water, Washington, DC. EPA-821-R-02-023.
19 Preparation and use of MI agar with a standard membrane filter procedure is set forth in the article, Brenner et al. 1993. ``New Medium for the
  Simultaneous Detection of Total Coliform and Escherichia coli in Water.'' Appl. Environ. Microbiol. 59:3534-3544 and in USEPA. 2002. Method 1604:
  Total Coliforms and Escherichia coli (E. coli) in Water by Membrane Filtration by Using a Simultaneous Detection Technique (MI Medium). U.S.
  Environmental Protection Agency, Office of Water, Washington, DC. EPA-821-R-02-024.
20 A description of the mColiBlue24 test, Total Coliforms and E. coli, is available from Hach Company, 100 Dayton Ave., Ames, IA 50010.

    For most PWSs, the time from sample collection to initiation of
analysis (i.e., the holding time) for source water E. coli samples may
not exceed 30 hours for all approved E. coli methods. However, if the
State determines on a case-by-case basis that analyzing an E. coli
sample within 30 hours is not feasible, the State may approve the
holding of an E. coli sample for up to 48 hours between collection and
initiation of analysis. E. coli samples held between 30 to 48 hours
must be analyzed by the Colilert reagent version of Standard Method
9223B as listed in 40 CFR 136.3. All E. coli samples must be maintained
below 10[deg] C and not allowed to freeze.
    The E. coli sample holding time established for source water
monitoring under the LT2ESWTR does not apply to E. coli sample holding
time requirements that have been established under other programs and
regulations.
b. Background and Analysis
    In the August 11, 2003 proposed LT2ESWTR, EPA planned to approve
the same E. coli methods that the Agency had proposed for ambient water
monitoring in an earlier rulemaking, ``Guidelines Establishing Test
Procedures for the Analysis of Pollutants; Analytical Methods for
Biological Pollutants in Ambient Water'' (USEPA 2001h). EPA selected
these methods based on data generated by EPA laboratories, submissions
to the EPA alternate test procedures program and voluntary consensus
standards bodies, peer reviewed journal articles, and publicly
available study reports.
    On July 21, 2003, EPA finalized ``Guidelines Establishing Test
Procedures for the Analysis of Pollutants; Analytical Methods for
Biological Pollutants in Ambient Water'' (USEPA 2003b). The only method
from the proposal of this rule that was not included in the final rule
was Colisure, which was excluded due to insufficient data on its
performance with surface water. For the other methods, EPA revised
certain titles and added method numbers to be consistent with other
microbiological methods, but the technical content of these methods in
the final rule did not change from the versions included in the
proposed rule.
    EPA is approving these same E. coli methods for analyses under the
LT2ESWTR. The source water E. coli analyses that PWSs will conduct
under the LT2ESWTR are similar to the ambient water analyses for which
EPA approved E. coli methods under ``Guidelines Establishing Test
Procedures for the Analysis of Pollutants; Analytical Methods for
Biological Pollutants in Ambient Water'' (USEPA 2003b). EPA continues
to support the findings of this rule and believes that the E. coli
methods approved therein have the necessary sensitivity and specificity
to meet the data quality objectives of the LT2ESWTR.
    An important aspect of monitoring for E. coli is the allowable
sample holding time (i.e., the time between sample collection and
initiation of analysis). Existing regulations, such as 40 CFR 141.74,
limit the holding time for E. coli samples to 8 hours. However, for
PWSs that must ship E. coli samples to an off-site laboratory for
analysis, meeting an 8 hour holding time is generally not feasible. For
example, during the ICRSS, all of the PWSs that shipped samples off-
site for E. coli analysis exceeded an 8 hour holding time, and 12
percent of these samples had holding times in excess of 30 hours.
    While most large PWSs that will monitor for E. coli under the
LT2ESWTR will conduct these analyses on-site, most small PWSs must ship
samples off-site to an approved laboratory. To address the concern that
PWSs using off-site laboratories cannot meet an 8-hour holding time,
EPA participated in studies to assess the effect of increased sample
holding time on E. coli analysis results. These studies are summarized
in the proposed rule (USEPA 2003a) and are described in detail in Pope
et al. (2003). Based on these studies, EPA has concluded that the
holding time for E. coli samples can be extended beyond 8 hours prior
to analysis without compromising the data quality objectives of
LT2ESWTR monitoring.
    In the proposed LT2ESWTR, EPA required analysis of E. coli samples
to be initiated within 24 hours of sample collection and required that
samples be kept below 10[deg] C and not allowed to freeze (USEPA
2003a). These proposed requirements were based on data showing that
most samples maintained within these temperature conditions were not
significantly different at 24 hours than at the standard holding time
of 8 hours. The proposal also noted that data indicated no significant
sample degradation after longer time periods, such as 30 or 48 hours,
for certain methods. Accordingly, EPA requested comment on establishing
a longer E. coli holding time in the final rule.
    For today's final rule, EPA is establishing a holding time of 30
hours for all approved E. coli methods. After reviewing public comment
on this issue, which is summarized in the following section, and
reassessing the studies described in the proposed rule, EPA has
concluded that a 30 hour holding time limit for E. coli samples is
appropriate and consistent with the data quality objectives of LT2ESWTR
source water monitoring. Further, EPA believes that meeting a 30 hour
holding time is feasible for most PWSs that must ship E. coli samples
to an off-site laboratory for analysis. This longer holding time,
however, does not apply to E. coli monitoring conducted under other
programs and regulations.
    EPA recognizes that in rare cases, having an E. coli sample
analyzed within 30 hours may not be feasible for a PWS due to distance
to an approved laboratory and limited transportation options. In these
cases, today's rule allows the State to approve up to a 48 hour holding
time for E. coli samples. Samples held between 30 to 48 hours must be
analyzed by the Colilert reagent version of Standard Method 9223B. This
is the only method evaluated in Pope et al. (2003) where no significant
sample degradation occurred at 48 hours.
    PWSs must maintain samples below 10[deg]C and not allow them to
freeze. EPA has developing guidance for PWSs on packing and shipping E.
coli samples to maintain these temperature conditions. See the overview
at the beginning of this section for information on how to access this
guidance.
c. Summary of Major Comments
    In the August 11, 2003 LT2ESWTR proposal, EPA requested comment on
whether the E. coli methods proposed for approval under the LT2ESWTR
are appropriate and whether there are additional methods not proposed
that should be considered. EPA also requested comment on the proposal
to extend the holding time for E. coli

samples to 24 hours; whether EPA should limit the extended holding time
to only those E. coli analytical methods that were evaluated in the
holding time studies described in the proposal; and whether EPA should
increase the source water E. coli holding time to 30 or 48 hours for
samples evaluated by one method, ONPG-MUG, and retain a 24-hour holding
time for samples analyzed by other methods.
    Most commenters stated that the proposed E. coli analytical methods
are appropriate. Commenters also agreed with the proposal to extend the
holding time for source water E. coli samples, but recommendations
about the maximum holding time and the methods to which the extended
holding time should apply differed among commenters. Some suggested
that EPA increase the holding time to 30 hours for the ONPG-MUG method,
but retain a 24-hour holding time for the other methods. Other
commenters recommended a 48-hour holding time for some or all methods.
Several commenters advised that holding times for all methods should be
the same to limit confusion. Some commenters were concerned that a 30-
hour holding time would not be sufficient for small PWSs in remote
areas to ship samples to distant laboratories.
    After consideration of the comments received, as well as the
holding time study data presented in the proposed rule and the time
required to ship samples off-site for analysis as evidenced in the
ICRSS, EPA has concluded that allowing a 30-hour holding time for all
E. coli methods approved under today's final rule is appropriate. Data
indicate that a 30-hour holding time for E. coli samples will not
adversely impact the data quality objectives of LT2ESWTR monitoring.
Further, establishing the same holding time for all methods will limit
confusion, and a 30-hour holding time will allow most PWSs that ship
samples off site for analysis to meet the holding time requirements.
Today's rule also allows the State to authorize a 48-hour holding time
for rare cases where a 30-hour holding time is not feasible.
4. Turbidity Methods
a. Today's Rule
    Today's rule requires PWSs to use the analytical methods that have
been previously approved by EPA for analysis of turbidity in drinking
water, as listed in 40 CFR 141.74. These are Method 2130B as published
in Standard Methods for the Examination of Water and Wastewater (APHA
1992), EPA Method 180.1 (USEPA 1993), Great Lakes Instruments Method 2
(Great Lakes Instruments 1992), and Hach FilterTrak Method 10133.
b. Background and Analysis
    As stated in section IV.A, today's rule requires filtered PWSs
serving at least 10,000 people to monitor for turbidity when they
conduct source water monitoring. EPA may use these data to modify the
indicator criteria that trigger Cryptosporidium monitoring by small
filtered PWSs, as recommended by the M-DBP Advisory Committee (USEPA
2000a). In addition, PWSs using conventional or direct filtration may
achieve additional Cryptosporidium treatment credit by demonstrating
very low turbidity in the combined filter effluent, as described in
section IV.D.7, or the individual filter effluent, as described in
section IV.D.8.
    The August 11, 2003 proposed LT2ESWTR required PWSs to use
turbidity methods that EPA had previously approved under 40 CFR 141.74
for analyzing drinking water (USEPA 2003a). These are EPA Method 180.1
and Standard Method 2130B, which are based on a comparison of the
intensity of light scattered by the sample with the intensity of light
scattered by a standard reference suspension; Great Lakes Instruments
Method 2, which is a modulated four beam infrared method using a
ratiometric algorithm to calculate the turbidity value from the four
readings that are produced; and Hach FilterTrak (Method 10133), which
is a laser-based method used to analyze finished drinking water.
    Today's final rule is unchanged from the proposal in regard to
analytical methods for turbidity. Hence, PWSs must use methods
currently approved in 40 CFR 141.74 for turbidity analysis. EPA
believes the currently approved methods are appropriate for turbidity
analyses that will be conducted under the LT2ESWTR. PWSs must use
turbidimeter instruments as described in the EPA-approved methods,
which may be either on-line or bench top instruments. If a PWS chooses
to use on-line instruments for monitoring turbidity, the PWS must
validate the continuous measurements for accuracy on a regular basis
using a protocol approved by the State, as required in 40 CFR 141.74.
c. Summary of Major Comments
    EPA received public comment on the turbidity methods required in
the August 11, 2003 proposed LT2ESWTR. While commenters, in general,
agreed that currently approved turbidity methods are adequate to meet
the requirements of the rule, several commenters were concerned with
turbidity measurement variation among different instruments. One
commenter suggested voluntary third party testing, while another
recommended more rigorous calibration and verification processes.
    As described in section IV.D.7, EPA has reviewed studies of low
level turbidity measurements, as well as standard test methods for
measurement of turbidity below 5 NTU. After reviewing this information,
EPA concluded that currently available monitoring equipment can
reliably measure turbidity at levels of 0.15 NTU and lower. However,
EPA agrees that rigorous calibration and maintenance of turbidity
monitoring equipment is necessary for PWSs pursuing the low filtered
water turbidity performance options in the microbial toolbox. EPA has
developed guidance on proper calibration, operation, and maintenance of
turbidimeters (USEPA 1999c).
    A few commenters stated that the LT2ESTWR does not recognize
advancements in turbidity measurement and newly developed turbidity
measurement technologies. In response, EPA has not received information
that supports approval of analytical methods for turbidity in addition
to those currently approved under 40 CFR 141.74, which are also
approved for turbidity monitoring under today's rule. If other
turbidity methods are approved and added to 40 CFR 141.74 in the
future, these methods will also be approved under the LT2ESWTR.
    One commenter requested that the LT2ESWTR specifically address
turbidity measurements in plants that practice lime softening. EPA
notes that additional treatment credit for combined filter effluent
turbidity is based on measurements collected under 40 CFR 141.173 or 40
CFR 141.551 (the IESWTR or LT1ESWTR). These regulations allow PWSs that
use lime softening to acidify samples prior to analysis in order to
address the effects of lime softening on turbidity measurements. In
regard to treatment credit based on individual filter effluent
turbidity, EPA does not believe that acidifying samples while measuring
turbidity every 15 minutes at each individual filter, as the IESWTR and
LT1ESWTR require, is feasible. However, PWSs that practice lime
softening could use the demonstration of performance toolbox option to
demonstrate that a plant is achieving removal efficiencies equivalent
to the additional credit allowed for individual filter performance.

K. Laboratory Approval

    Given the potentially significant implications for PWSs and
drinking water consumers of microbial monitoring under the LT2ESWTR,
laboratory analyses for Cryptosporidium, E. coli, and turbidity should
be accurate and reliable within the limits of approved methods.
Therefore, today's final rule requires PWSs to use laboratories that
have been approved to conduct analyses for these parameters by EPA or
the State.
1. Cryptosporidium Laboratory Approval
a. Today's Rule
    Analysis of samples for Cryptosporidium under today's rule must be
conducted by a laboratory that is approved under EPA's Laboratory
Quality Assurance Evaluation Program (Lab QA Program) for Analysis of
Cryptosporidium in Water (described in 67 FR 9731, March 4, 2002, USEPA
2002d). A list of laboratories that are approved under this program is
available on the Internet at http://www.epa.gov/safewater/disinfection/lt2. If

a State adopts an equivalent approval process under a State laboratory
certification program, then PWSs can use laboratories approved by the
State.
b. Background and Analysis
    Because States do not currently approve laboratories for
Cryptosporidium analyses, EPA has assumed initial responsibility for
Cryptosporidium laboratory approval. EPA initiated the Cryptosporidium
Lab QA Program prior to LT2ESWTR promulgation to ensure that adequate
analytical capacity will be available at approved laboratories to
support required monitoring, which begins 6 months after rule
promulgation. The August 11, 2003 proposed LT2ESWTR required PWSs to
have Cryptosporidium samples analyzed by laboratories approved under
the EPA Lab QA Program. Today's final rule is unchanged from the
proposal with respect to this requirement.
    Laboratories seeking approval under the EPA Lab QA Program for
Cryptosporidium analysis must submit an interest application to EPA,
successfully analyze a set of initial performance testing samples, and
undergo an on-site evaluation. Laboratories that pass the quality
assurance evaluation are approved for Cryptosporidium analysis under
the LT2ESWTR. To maintain approval, laboratories must successfully
analyze a set of three ongoing proficiency testing samples
approximately every four months. The Lab QA Program is described in
detail in USEPA (2002d) and additional information can be found on the
Internet at http://www.epa.gov/safewater/disinfection/lt2.

    EPA tracks the Cryptosporidium sample analysis capacity of approved
laboratories through the Lab QA Program. Using information provided by
laboratories, EPA expects that existing capacity should be sufficient
to support initial source water monitoring by large PWSs under the
LT2ESWTR. Further, the implementation schedule for today's rule, which
is described in section IV.G, provides time for laboratories to
increase capacity through steps like training new analysts as the
demand for sample analysis grows.
c. Summary of Major Comments
    In regard to approval of laboratories for Cryptosporidium analysis,
major comments on the August 11, 2003 proposal addressed the following
issues: laboratory capacity, State approval programs, and analyst
experience criteria. Comments regarding Cryptosporidium laboratory
capacity are summarized in section IV.G, while those on the other
issues are summarized as follows.
    EPA requested comment on States approving Cryptosporidium
laboratories. Most commenters, however, recommended that EPA maintain
the Lab QA Program, due to the specialized nature of the work. EPA
intends to maintain the Lab QA Program, but today's rule does allow
States to certify Cryptosporidium laboratories by setting up an
equivalent program.
    EPA also requested comment on the experience criteria that Methods
1622 and 1623 include for Cryptosporidium analysts. Some commenters
recommended lowering analyst training and experience requirements,
while others recommended no change or an increase in microscopy
training. After evaluating these comments, EPA has concluded that the
analyst criteria included in Methods 1622 and 1623 are reasonable for
ensuring that analysts have the experience to evaluate source water
samples under today's rule. Consequently, EPA has not altered these
criteria from the approved methods.
2. E. coli Laboratory Approval
a. Today's Rule
    PWSs must have E. coli samples analyzed by a laboratory that has
been certified by EPA, the National Environmental Laboratory
Accreditation Conference (NELAC) or the State for total coliform or
fecal coliform analysis in drinking water under 40 CFR 141.74. The
laboratory must use the same technique for E. coli analysis under
today's rule that the laboratory is certified to use for drinking water
under 40 CFR 141.74 (e.g., membrane filtration, multiple-well,
multiple-tube).
b. Background and Analysis
    The August 11, 2003 proposed LT2ESWTR required PWSs to have E. coli
samples analyzed by laboratories that are certified to conduct total or
fecal coliform analyses in drinking water (i.e., under 40 CFR 141.74)
by EPA, NELAC or the State. The proposal required laboratories to use
the same E. coli analytical technique that they are certified to use
for coliform analyses in drinking water. Today's final rule is
unchanged from the proposal in regard to these requirements. EPA
believes that laboratories that are certified to conduct coliform
analyses in drinking water have the expertise to conduct E. coli
analyses under today's rule, provided they use the analytical technique
for which they are certified.
c. Summary of Major Comments
    Two commenters on the August 11, 2003 proposal suggested that
laboratories should be certified specifically for quantitative analyses
of total or fecal coliform in a source water matrix. However, the
methods approved for source water E. coli analyses under today's rule
are also approved under the drinking water certification program. EPA
believes that analysts certified for these methods under the drinking
water certification program have the capability to perform the same
methods for a source water matrix, even though additional steps may be
required (such as dilutions). EPA has revised the Laboratory
Certification Manual to suggest Performance Evaluation (PE) samples for
source water matrix analyses and States have the option to require PE
samples as needed in their State laboratory certification programs.
3. Turbidity Analyst Approval
a. Today's Rule
    Under today's rule, measurements of turbidity must be made by a
party approved by the State.
b. Background and Analysis
    The August 11, 2003 proposed LT2ESWTR required that measurements of
turbidity be made by a party approved by the State. This reflects
existing requirements in 40 CFR 141.74 for measurement of turbidity in
drinking water. Today's final rule is unchanged from the proposal in
this respect.

c. Summary of Major Comments
    Commenters on requirements for turbidity analyst approval in the
August 11, 2003 proposal agreed that turbidity analyses should be
consistent with 40 CFR 141.74. Specifically, any person that is
currently approved to conduct turbidity analysis under existing
drinking water regulations should be approved to conduct turbidity
analyses under the LT2ESWTR. EPA agrees with this comment and it is
reflected in today's final rule.

L. Requirements for Sanitary Surveys Conducted by EPA

1. Today's Rule
    Today's final rule establishes requirements for PWSs to respond to
significant deficiencies identified in sanitary surveys that EPA
conducts. These requirements give EPA authority equivalent to that
exercised by States under existing regulations to ensure that PWSs
address significant deficiencies.
     For sanitary surveys conducted by EPA under SDWA section
1445 or other authority, PWSs must respond in writing to significant
deficiencies outlined in sanitary survey reports no later than 45 days
after receipt of the report, indicating how and on what schedule the
PWS will address significant deficiencies noted in the survey.
     PWSs must correct significant deficiencies identified in
sanitary survey reports according to the schedule approved by EPA, or
if there is no approved schedule, according to the schedule the PWS
reported if such deficiencies are within the control of the PWS.
     A sanitary survey, as conducted by EPA, is an onsite
review of the water source (identifying sources of contamination by
using results of source water assessments where available), facilities,
equipment, operation, maintenance, and monitoring compliance of a PWS
to evaluate the adequacy of the PWS, its sources and operations, and
the distribution of safe drinking water. A significant deficiency
includes a defect in design, operation, or maintenance, or a failure or
malfunction of the sources, treatment, storage, or distribution system
that EPA determines to be causing, or has the potential for causing the
introduction of contamination into the water delivered to consumers.
2. Background and Analysis
    As established by the IESWTR in 40 CFR 142.16(b)(3), primacy States
must conduct sanitary surveys for PWSs using surface water sources
every three or five years. The sanitary survey is an onsite review of
the following: (1) Source, (2) treatment, (3) distribution system, (4)
finished water storage, (5) pumps, pump facilities, and controls, (6)
monitoring, reporting, and data verification, (7) system management and
operation, and (8) operator compliance with State requirements.
    Under the IESWTR, primacy States must have the authority to assure
that PWSs respond in writing to significant deficiencies identified in
sanitary survey reports no later than 45 days after receipt of the
report, indicating how and on what schedule the system will address the
deficiency (40 CFR 142.16(b)(1)(ii)). Further, primacy States must have
the authority to assure that systems take necessary steps to address
significant deficiencies identified in sanitary survey reports if such
deficiencies are within the control of the system and its governing
body (40 CFR 142.16(b)(1)(iii)).
    EPA conducts sanitary surveys under SDWA section 1445 for PWSs not
regulated by primacy States (e.g., Tribal systems, Wyoming). However,
the authority required of primacy States under 40 CFR 142 to ensure
that PWSs address significant deficiencies identified during sanitary
surveys does not extend to EPA. Consequently, the sanitary survey
requirements established by the IESWTR created an unequal standard.
PWSs regulated by primacy States are subject to the States' authority
to require correction of significant deficiencies noted in sanitary
survey reports, while PWSs for which EPA has direct implementation
authority did not have to meet an equivalent requirement.
    In the August 11, 2003 proposal, EPA requested comment on
establishing requirements under 40 CFR 141 for PWSs to correct
significant deficiencies identified in sanitary surveys conducted by
EPA. The requirements in today's final rule follow closely on the
language presented in the proposal. Today's rule ensures that PWSs in
non-primacy States are subject to comparable requirements for sanitary
surveys as PWS regulated by States with primacy.
3. Summary of Major Comments
    Most public comment on the August 11, 2003 proposal supported
requiring PWSs to correct significant deficiencies identified in
sanitary surveys conducted by EPA. Commenters stated that requirements
for sanitary surveys should be consistent for PWSs and should not
depend on the primacy agency. EPA believes the requirements in today's
final rule will establish this consistency.
    One commenter requested that EPA include a process for PWSs to
appeal a significant deficiency determination. EPA expects that PWSs
will raise any concerns regarding significant deficiency determinations
with the primacy agency, either the State or EPA, that conducts the
sanitary survey. States or EPA may withdraw or amend their significant
deficiency determinations as appropriate. The IESWTR did not establish
a separate appeal process for sanitary surveys conducted by States, and
EPA has not established such a process for sanitary surveys conducted
by EPA under today's rule.

M. Variances and Exemptions

    SDWA section 1415 allows States to grant variances from national
primary drinking water regulations under certain conditions; section
1416 establishes the conditions under which States may grant exemptions
to MCL or treatment technique requirements. These conditions and EPA's
view on their applicability to the LT2ESWTR are summarized as follows:
1. Variances
    Section 1415 specifies two provisions under which general variances
to treatment technique requirements may be granted:

    (1) A State that has primacy may grant a variance to a PWS from
any requirement to use a specified treatment technique for a
contaminant if the PWS demonstrates to the satisfaction of the State
that the treatment technique is not necessary to protect public
health because of the nature of the PWS's raw water source. EPA may
prescribe monitoring and other requirements as conditions of the
variance (section 1415(a)(1)(B)).
    (2) EPA may grant a variance from any treatment technique
requirement upon a showing by any person that an alternative
treatment technique not included in such requirement is at least as
efficient in lowering the level of the contaminant (section
1415(a)(3)).

    EPA does not believe that the first variance provision is
applicable to filtered PWSs under today's rule. Filtered PWSs are
required to implement additional treatment under the LT2ESWTR only when
source water monitoring demonstrates higher levels of Cryptosporidium
contamination. Thus, this treatment technique requirement accounts for
the nature of the PWS's raw water source. Unfiltered PWS treatment
requirements also account for the nature of a PWS's raw water source
with respect to whether 2-or 3-log Cryptosporidium inactivation is
required.
    In theory, the first variance provision could be applied to the
requirement that all unfiltered PWSs provide at least 2-

log Cryptosporidium inactivation. If an unfiltered PWS could show a raw
water Cryptosporidium level 3-log lower than the Bin 1 cutoff for
filtered PWSs (i.e., below 0.075 oocysts/1,000 L), this could
demonstrate that no treatment for Cryptosporidium is necessary. The
unfiltered PWS would already be achieving public health protection
against Cryptosporidium equivalent to filtered PWSs due to the nature
of the raw water source.
    In practice, EPA has not identified an approach that is
economically or technologically feasible for a PWS to demonstrate such
a low level of Cryptosporidium to support granting a variance. This is
due to the extremely large volume and number of samples that would be
necessary to make such a demonstration with confidence. However,
unfiltered PWSs may choose to pursue the development and implementation
of monitoring programs to apply for a variance from Cryptosporidium
inactivation requirements based on the nature of the raw water source.
A sufficient monitoring program may be feasible in site-specific
circumstances or with the use of innovative approaches.
    The second provision for granting a variance is not applicable to
the LT2ESWTR because the rule provides broad flexibility in how PWSs
achieve the required level of Cryptosporidium reduction through the
microbial toolbox. Moreover, the microbial toolbox contains an option
for Demonstration of Performance, under which States can award
treatment credit based on the demonstrated efficiency of a treatment
process in reducing Cryptosporidium levels. Thus, there is no need for
this type of variance under the LT2ESWTR.
    SDWA section 1415(e) describes small PWS variances, but these
cannot be granted for a treatment technique for a microbial
contaminant. Hence, small PWS variances are not allowed for the
LT2ESWTR.
2. Exemptions
    Under SDWA section 1416(a), a State may exempt any PWS from a
treatment technique requirement upon a finding that (1) Due to
compelling factors (which may include economic factors such as
qualification of the PWS as serving a disadvantaged community), the PWS
is unable to comply with the requirement or implement measures to
develop an alternative source of water supply; (2) the PWS was in
operation on the effective date of the treatment technique requirement,
or for a PWS that was not in operation by that date, no reasonable
alternative source of drinking water is available to the new PWS; (3)
the exemption will not result in an unreasonable risk to health; and
(4) management or restructuring changes (or both) cannot reasonably
result in compliance with the Act or improve the quality of drinking
water.
    EPA believes that granting an exemption to the Cryptosporidium
treatment requirements of the LT2ESWTR would result in an unreasonable
risk to health. As described in section III.C, Cryptosporidium causes
acute health effects, which may be severe in sensitive subpopulations
and include risk of mortality. Moreover, the additional Cryptosporidium
treatment requirements of the LT2ESWTR are targeted to PWSs with the
highest degree of risk. Due to these factors, EPA does not support the
granting exemptions from the LT2ESWTR.

V. State Implementation

A. Today's Rule

    This section describes the regulations and other procedures and
policies States must adopt to implement today's rule. States must
continue to meet all other conditions of primacy in 40 CFR Part 142. To
implement the LT2ESWTR, States must adopt revisions to the following
sections:

Sec.  141.2--Definitions
Subpart Q--Public Notification
New Subpart W--Additional treatment technique requirements for
Cryptosporidium
Sec.  142.14--Records kept by States
Sec.  142.15--Reports by States
Sec.  142.16--Special primacy requirements
1. Special State primacy requirements
    To ensure that a State program includes all the elements necessary
for an effective and enforceable program under today's rule, a State
primacy application must include a description of how the State will
perform the following:
     Approve an alternative to the E. coli levels that trigger
Cryptosporidium monitoring by filtered systems serving fewer than
10,000 people (see section IV.A.1);
     Approve watershed control programs for the 0.5 log
watershed control program credit in the microbial toolbox (see section
IV.D.2);
     Assess significant changes in the watershed and source
water as part of the sanitary survey process and determine appropriate
follow-up action (see section IV.A); and
     Approve protocols for treatment credit under the
Demonstration of Performance toolbox option (see section IV.D.9), for
site specific chlorine dioxide and ozone CT tables (see section
IV.D.14), and for alternative UV reactor validation testing (see
section IV.D.15).
    A State program can be more, but not less, stringent than Federal
regulations. As such, some of the elements listed here may not be
applicable to a specific State program.
2. State Recordkeeping Requirements
    Today's rule requires States to keep additional records of the
following, including all supporting information and an explanation of
the technical basis for each decision:
     Results of source water E. coli and Cryptosporidium
monitoring for not less than 1 year;
     Cryptosporidium treatment bin classification for each
filtered PWS after the initial and after the second round of source
water monitoring. Also, any change in treatment requirements for
filtered systems due to watershed assessment during sanitary surveys;
     Determination of whether each unfiltered PWS has a mean
source water Cryptosporidium level above 0.01 oocysts/L after the
initial and after the second round of source water monitoring;
     The treatment processes or control measures that each PWS
employs to meet Cryptosporidium treatment requirements under the
LT2ESWTR, including measures that systems may use for only part of the
year; and
     A list of PWSs required to cover or treat the effluent of
an uncovered finished water storage facilities.
3. State Reporting Requirements
    Today's rule requires States to report the following information:
     The Cryptosporidium treatment bin classification for each
filtered PWS after the initial and after the second round of source
water monitoring. Also, any change in treatment requirements for
filtered systems due to watershed assessment during sanitary surveys;
and
     The determination of whether each unfiltered PWS has a
mean source water Cryptosporidium level above 0.01 oocysts/L after the
initial and after the second round of source water monitoring.
4. Interim Primacy
    States that have primacy (including interim primacy) for every
existing NPDWR already in effect may obtain interim primacy for this
rule, beginning on the date that the State submits the application for
this rule to USEPA, or the effective date of its revised regulations,
whichever is later. A State that wishes to obtain interim primacy

for future NPDWRs must obtain primacy for today's rule. As described in
Section IV.A, EPA expects to work with States to oversee the initial
source water monitoring that begins six months following rule
promulgation.

B. Background and Analysis

    SDWA establishes requirements that a State or eligible Indian Tribe
must meet to assume and maintain primary enforcement responsibility
(primacy) for its PWSs. These requirements include the following
activities: (1) Adopting drinking water regulations that are no less
stringent than Federal drinking water regulations; (2) adopting and
implementing adequate procedures for enforcement; (3) keeping records
and making reports available on activities that EPA requires by
regulation; (4) issuing variances and exemptions (if allowed by the
State), under conditions no less stringent than allowed under SDWA; and
(5) adopting and being capable of implementing an adequate plan for the
provisions of safe drinking water under emergency situations.
    40 CFR part 142 sets out the specific program implementation
requirements for States to obtain primacy for the public water supply
supervision program as authorized under SDWA section 1413. In addition
to adopting basic primacy requirements specified in 40 CFR Part 142,
States may be required to adopt special primacy provisions pertaining
to specific regulations where implementation of the rule involves
activities beyond general primacy provisions. States must include these
regulation specific provisions in an application for approval of their
program revision.
    The current regulations in 40 CFR 142.14 require States with
primacy to keep various records, including the following: analytical
results to determine compliance with MCLs, MRDLs, and treatment
technique requirements; PWS inventories; State approvals; enforcement
actions; and the issuance of variances and exemptions. Today's final
rule requires States to keep additional records, including all
supporting information and an explanation of the technical basis for
decisions made by the State regarding today's rule requirements. EPA
currently requires in 40 CFR 142.15 that States report to EPA
information such as violations, variance and exemption status, and
enforcement actions, and today's rule adds additional reporting
requirements related to monitoring and treatment requirements.
    On April 28, 1998, EPA amended its State primacy regulations at 40
CFR 142.12 to incorporate the new process identified in the 1996 SDWA
Amendments for granting primary enforcement authority to States while
their applications to modify their primacy programs are under review
(63 FR 23362, April 28, 1998) (USEPA 1998c). The new process grants
interim primary enforcement authority for a new or revised regulation
during the period in which EPA is making a determination with regard to
primacy for that new or revised regulation. This interim enforcement
authority begins on the date of the primacy application submission or
the effective date of the new or revised State regulation, whichever is
later, and ends when EPA makes a final determination. However, this
interim primacy authority is only available to a State that has primacy
(including interim primacy) for every existing NPDWR in effect when the
new regulation is promulgated. States that have primacy for every
existing NPDWR already in effect may obtain interim primacy for this
rule and a State that wishes to obtain interim primacy for future
NPDWRs must obtain primacy for this rule.

C. Summary of Major Comments

    Public comment generally supported the special primacy requirements
in the August 11, 2003 proposal, and many commenters expressed
appreciation for the flexibility the special primacy requirements
provided to States. One commenter expressed concern that a State that
adopted this rule by reference would lose the flexibility intended in
the proposal. In response, EPA recognizes that some States may be
limited by their statutes in applying the flexibility allowed under
today's rule. However, EPA believes that providing flexibility for
States to approve site-specific approaches that achieve the public
health goals of the LT2ESWTR is appropriate and will benefit some
States and PWSs.
    A few commenters were concerned that the special primacy
requirement to assess changes in watersheds as part of the sanitary
survey process would be difficult to meet due to a lack of resources or
large watersheds that overlap State boundaries. In response, EPA notes
that States are required to evaluate PWS sources under the existing
sanitary survey requirements (40 CFR 142.16(b)(3)). If a State
determines during a sanitary survey that significant changes have
occurred in the watershed that could lead to increased contamination of
the source by Cryptosporidium, today's rule gives the State the
authority to require the PWS to take actions to mitigate or treat the
contamination. Because the treatment requirements in today's rule
depend on the degree of source water contamination, EPA believes that
this assessment of changes in a PWS's source water following initial
bin classification is necessary.
    EPA also received comments on State approval processes for
laboratories analyzing for Cryptosporidium to meet LT2ESWTR
requirements. Most commenters stated that EPA should maintain a
national certification program for laboratories approved for
Cryptosporidium analysis for LT2ESTWR compliance. Commenters indicated
that requiring States to approve laboratories for Cryptosporidium
analysis placed too great a demand on State resources. Today's rule
does not include a State primacy requirement for laboratory
certification for Cryptosporidium analysis.
    Some commenters were concerned with the data tracking and review
burden on States from the reporting requirements for the individual
toolbox components. EPA agrees with commenters that, in some cases,
allowing PWSs to report summaries or to self-certify that the PWS met
the performance requirements for microbial toolbox treatment credit may
be appropriate. Today's rule allow States to modify the level of
reporting required for toolbox components and specifically, permit PWSs
to self-certify to the State that a toolbox component has met its
performance requirements.

VI. Economic Analysis

    This section summarizes the economic analysis (EA) for the final
LT2ESWTR. The EA is an assessment of the benefits, both health and
nonhealth-related, and costs to the regulated community of the final
regulation, along with those of regulatory alternatives that the Agency
considered. EPA developed the EA to meet the requirement of SDWA
section 1412(b)(3)(C) for a Health Risk Reduction and Cost Analysis
(HRRCA), as well as the requirements of Executive Order 12866,
Regulatory Planning and Review, under which EPA must estimate the costs
and benefits of the LT2ESWTR. The full EA is presented in Economic
Analysis for the Long Term 2 Enhanced Surface Water Treatment Rule
(USEPA 2005a), which includes additional details and discussion on the
topics presented throughout this section of the preamble.
    The LT2ESWTR is the second in a staged set of rules that address
public health risks from microbial contamination of surface and GWUDI
drinking water supplies and, more specifically, prevent Cryptosporidium

from reaching consumers. As described in section III, EPA promulgated
the IESWTR and LT1ESWTR to provide a baseline of protection against
Cryptosporidium in large and small PWSs, respectively. Today's final
rule will achieve further reductions in Cryptosporidium exposure for
PWSs with the highest vulnerability. This EA considers only the
incremental reduction in exposure beyond the two previously promulgated
rules (IESWTR and LT1ESWTR) from the alternatives evaluated for the
LT2ESWTR.

A. What Regulatory Alternatives Did the Agency Consider?

    Regulatory alternatives considered by the Agency for the LT2ESWTR
were developed through the deliberations of the Stage 2 M-DBP Federal
Advisory Committee (described in section III). The Advisory Committee
considered several general approaches for reducing the risk from
Cryptosporidium in drinking water. These approaches included both
additional treatment requirements for all PWSs and risk-targeted
treatment requirements for PWSs with the highest vulnerability to
Cryptosporidium following implementation of the IESWTR and LT1ESWTR. In
addition, the Advisory Committee considered related issues such as
alternative monitoring strategies.
    After considering these general approaches, the Advisory Committee
focused on four regulatory alternatives for filtered PWSs (see Table
VI.A-1). With the exception of Alternative 1, which requires all PWSs
to provide additional treatment for Cryptosporidium, these alternatives
incorporate a risk-targeting approach in which PWSs are classified in
different treatment bins based on the results of source water
monitoring. Additional Cryptosporidium treatment requirements are
directly linked to the treatment bin classification. Accordingly, these
rule alternatives are differentiated by two criteria: (1) The
Cryptosporidium concentrations that define the bin boundaries and (2)
the degree of treatment required for each bin.
    The Advisory Committee reached consensus regarding additional
treatment requirements for unfiltered PWSs without formally identifying
regulatory alternatives other than requiring no treatment for
Cryptosporidium (i.e., no new regulation).

   Table VI.A-1.--Summary of Regulatory Alternatives for Filtered PWSs
------------------------------------------------------------------------
     Mean source water Cryptosporidium          Additional treatment
       monitoring result (oocysts/L)              requirements \1\
------------------------------------------------------------------------
                             Alternative A1
------------------------------------------------------------------------
               2.0-log inactivation required for all PWSs
------------------------------------------------------------------------
                             Alternative A2
------------------------------------------------------------------------
<  0.03....................................  No additional treatment.
>= 0.03 and < 0.1.........................  0.5-log.
>= 0.1 and < 1.0..........................  1.5-log.
>= 1.0....................................  2.5-log.
-------------------------------------------
                   Alternative A3--Today's Final Rule
------------------------------------------------------------------------
<  0.075...................................  No additional treatment.
>= 0.075 and < 1.0........................  1-log.
>= 1.0 and < 3.0..........................  2-log.
>= 3.0....................................  2.5-log.
-------------------------------------------
                             Alternative A4
------------------------------------------------------------------------
<  0.1.....................................  No additional treatment.
>= 0.1 and < 1.0..........................  0.5-log.
>=1.0.....................................  1.0-log.
------------------------------------------------------------------------
\1\ Note: ``Additional treatment requirements'' are in addition to
  levels already required under existing rules (e.g., the IESWTR and
  LT1ESWTR) for PWSs using conventional treatment or equivalent.

B. What Analyses Support Today's Final Rule?

    EPA has quantified benefits and costs for each of the filtered PWS
regulatory alternatives in Table VI.A-1 and for unfiltered PWS
requirements. Quantified benefits stem from estimated reductions in the
incidence of cryptosporidiosis resulting from the regulation. To make
these estimates, the Agency employed Monte Carlo modeling to account
for uncertainty and variability in key parameters like Cryptosporidium
occurrence, infectivity, and treatment efficiency. Costs result largely
from the installation of additional treatment, with lesser costs due to
monitoring and other implementation activities.
    Cryptosporidium occurrence significantly influences the estimated
benefits and costs of regulatory alternatives. As discussed in section
III.E, EPA analyzed data collected under the ICR, the ICR Supplemental
Surveys of medium PWSs (ICRSSM), and the ICR Supplemental Surveys of
large PWSs (ICRSSL) to estimate the national occurrence distribution of
Cryptosporidium in surface water. EPA evaluated these distributions
independently when assessing benefits and costs for different
regulatory alternatives.
    Another parameter that significantly influences estimated benefits
is Cryptosporidium infectivity (i.e., the likelihood of infection after
exposure to a given dose of Cryptosporidium). As discussed in section
III.E, EPA considered results from human volunteer feeding studies and
applied six different model forms to estimate dose-response
relationships.
    To address uncertainty in these estimates, benefits are presented
for three different dose response models: A ``high'' estimate based on
the model that showed the highest mean baseline risk, a ``medium''
estimate based on the model and data used at proposal, which is in the
middle of the range of estimates produced by the six models, and a
``low'' estimate, based on the model that showed the lowest mean
baseline risk. These estimates are not upper and lower bounds. For each
model, a distribution of effects is estimated, and the ``high'' and
``low'' estimates show only the means of these distributions for two
different model choices.
    Both benefits and costs are determined as annualized present
values, which allows comparison of cost and benefit streams that are
variable over time. The time frame used for both benefit and cost
comparisons is 25 years. The Agency uses social discount rates of both
3 percent and 7 percent to calculate present values from the stream of
benefits and costs and also to annualize the present value estimates
over 25 years (see EPA's Guidelines for Preparing Economic Analyses
(USEPA 2000c) for a discussion of social discount rates).
    Results of these analyses are summarized in this section of the
preamble. Detailed results and descriptions of the supporting analyzes
are shown in the LT2ESWTR EA (USEPA 2005a).
    In evaluating the regulatory alternatives shown in Table VI.A-1,
EPA and the Advisory Committee were concerned with the following
questions: (1) Do the treatment requirements adequately control
Cryptosporidium concentrations in finished water? (2) How many PWSs
will be required to add treatment? and (3) What is the likelihood that
PWSs will be misclassified in higher or lower treatment bins through
monitoring?
    Consistent with the consensus recommendation of the Advisory
Committee, EPA selected Alternative A3 for today's final rule. EPA has
determined that this alternative will significantly reduce the
incidence of cryptosporidiosis due to drinking water

in vulnerable PWSs and is feasible for PWSs to implement.
    Alternative A1 (across-the-board 2-log inactivation) was not
selected because it would impose costs but provide few benefits to PWSs
with relatively low Cryptosporidium risk. EPA was also concerned about
the feasibility of requiring every surface water treatment plant to
install additional treatment processes (e.g., UV) for Cryptosporidium.
With Alternative A2, EPA was concerned with the feasibility of
accurately classifying PWSs in treatment bins at a Cryptosporidium
concentration of 0.03 oocysts/L. EPA does not believe that Alternative
A4 would reduce risks from Cryptosporidium in vulnerable PWSs to the
extent feasible, as required under SDWA section 1412(b)(7)(A), because
of the low levels of treatment required.

C. What Are the Benefits of the LT2ESWTR?

    EPA has quantified and monetized health benefits for reductions in
endemic cryptosporidiosis due to the LT2ESWTR. In addition, today's
rule is expected to provide additional health and nonhealth-related
benefits that EPA was unable to quantify. Table VI.C-1 summarizes these
unquantified benefits.
1. Nonquantified Benefits

                                Table VI.C-1.--Summary of Nonquantified Benefits
----------------------------------------------------------------------------------------------------------------
              Benefit type                     Potential effect on benefits                  Comments
----------------------------------------------------------------------------------------------------------------
Reducing outbreak risks and response      Increase.............................  Some human or equipment
 costs.                                                                           failures may occur even with
                                                                                the requirements of today's
                                                                                rule; however, by adding
                                                                                barriers of protection for
                                                                                some PWSs, the rule will
                                                                                reduce the possibility of such
                                                                                failures leading to outbreaks.
Reducing averting behavior (e.g.,         Increase/No Change...................  Consumers in PWSs that cease
 boiling tap water or purchasing bottled                                          using uncovered finished water
 water).                                                                          reservoirs (through covering
                                                                                or taking such reservoirs off-
                                                                                line) may have greater
                                                                                confidence in water quality.
                                                                                This may result in less
                                                                                averting behavior that reduces
                                                                                both out-of-pocket costs
                                                                                (e.g., purchase of bottled
                                                                                water) and opportunity costs
                                                                                (e.g., time to boil water).
Improving aesthetic water quality.......  Increase.............................  Some technologies installed for
                                                                                this rule (e.g., ozone) are
                                                                                likely to reduce taste and
                                                                                odor problems.
Reducing risk from co-occurring and       Increase.............................  Although focused on removal of
 emerging pathogens.                                                              Cryptosporidium from drinking
                                                                                water, PWSs that change
                                                                                treatment processes will also
                                                                                increase removal of pathogens
                                                                                that the rule does not
                                                                                specifically regulate.
Increased source water monitoring.......  Increase.............................  The greater understanding of
                                                                                source water quality that
                                                                                results from monitoring may
                                                                                enhance the ability of plants
                                                                                to optimize treatment
                                                                                operations in ways other than
                                                                                those addressed in this rule.
Reduced contamination due to covering or  Increase.............................  Contaminants introduced through
 treating finished water storage                                                  uncovered finished water
 facilities.                                                                      storage facilities will be
                                                                                reduced, which will produce
                                                                                positive public health
                                                                                benefits.
Change in the levels of disinfection      Increase/Decrease....................  PWSs that install ozone to
 byproducts.                                                                      comply with the LT2ESWTR may
                                                                                experience an increase in
                                                                                certain DBPs. PWSs that
                                                                                install UV or microfiltration
                                                                                may reduce the use of chlorine
                                                                                and experience a decrease in
                                                                                DBPs.
----------------------------------------------------------------------------------------------------------------
 Source: Chapter 5 of the LT2ESWTR Economic Analysis (USEPA 2005a).

2. Quantified Benefits
    In quantifying benefits for the LT2ESWTR based on reductions in the
risk of endemic cryptosporidiosis, EPA considered several categories of
monetized benefits. First, EPA estimated the number of cases expected
to result in premature mortality (primarily for members of sensitive
subpopulations such as AIDS patients). The mortality estimate was
developed using data from the Milwaukee cryptosporidiosis outbreak of
1993 (described in section III), with adjustments to account for the
subsequent decrease in the mortality rate among people with AIDS and
for the difference between the portion of people living with AIDS in
1993 in Milwaukee and the current and projected national levels. EPA
estimated a mortality rate of 26.3 deaths per 100,000 illnesses for
those served by unfiltered PWSs and a mortality rate of 16.7 deaths per
100,000 illnesses for those served by filtered PWSs. These different
rates are associated with the incidence of AIDS in populations served
by unfiltered and filtered PWSs. A complete discussion on how EPA
derived these rates can be found in subchapter 5.2 of the LT2ESWTR EA
(USEPA 2005a).
    Reductions in mortalities were monetized using EPA's standard
methodology for monetizing mortality risk reduction. This methodology
is based on a distribution of value of statistical life (VSL) estimates
from 26 labor market and stated preference studies. The mean VSL is
$7.4 million in 2005 with a 5th to 95th percentile range of $1.2 to
$16.9 million. A more detailed discussion of these studies and the VSL
estimate can be found in EPA's Guidelines for Preparing Economic
Analyses (USEPA 2000c). A real income growth factor was applied to
these estimates of approximately 1.9 percent per year for the 20-year
time span following implementation. Income elasticity for VSL was
estimated as a triangular distribution that ranged from 0.08 to 1.00,
with a mode of 0.40. VSL values for the 20-year span are shown in the
LT2ESWTR EA in Exhibit 5.24 (USEPA 2005a).
    The substantial majority of cases are not expected to be fatal and
the Agency separately estimated the value of non-fatal illnesses
avoided that would result from the LT2ESWTR. For these, EPA first
divided projected cases into three categories, mild, moderate, and
severe, and then calculated a monetized value per case avoided for each
severity level. These were then combined into a weighted average value
per case based on the relative frequency of each severity level.
According to a study conducted by Corso et al. (2003), the majority of
illness fall into the mild category (88 percent). Approximately 11
percent of illness fall into the moderate category, which is defined as
those who seek medical treatment but are not hospitalized. The final 1
percent have severe symptoms that result in hospitalization. EPA
estimated different medical expenses and time losses for each category.
    Benefits for non-fatal cases were calculated using a cost-of-
illness (COI)

approach. Traditional COI valuations focus on medical costs and lost
wages, and leave out significant categories of benefits, specifically
the reduced utility from being sick (i.e., lost personal or non-work
time, including activities such as child care, homemaking, community
service, time spent with family, recreation, and pain and suffering),
although some COI studies also include an estimate for unpaid labor
(household production) valued at an estimated wage rate designed to
reflect the market value of such labor (e.g., median wage for household
domestic labor). Ideally, a comprehensive willingness to pay (WTP)
estimate would be used that includes all categories of loss in a single
number. However, a review of the literature indicated that the
available studies were not suitable for valuing cryptosporidiosis;
hence, estimates from this literature are inappropriate for use in this
analysis. Instead, EPA presents two COI estimates: A traditional
approach that only includes valuation for medical costs and lost work
time (including some portion of unpaid household production); and an
enhanced approach that also factors in valuations for lost unpaid work
time for employed people, reduced utility (or sense of well-being)
associated with decreased enjoyment of time spent in non-work
activities, and lost productivity at work on days when paid workers are
ill but go to work anyway.
    Table VI.C-2 shows the various categories of loss and how they were
valued for each estimate for a ``typical'' case in 2003 (weighted
average based on severity level).

Table VI.C-2.--Traditional and Enhanced COI for Cryptosporidiosis, 2003$
                    [Weighted average cost per case]
------------------------------------------------------------------------
          Loss category               Traditional COI      Enhanced COI
------------------------------------------------------------------------
Direct Medical Costs.............  $106.91                        106.91
Lost Paid Work Days..............  120.13                         120.13
Lost Unpaid Work Days \1\........  24.32                           48.64
Lost Leisure Time \2\............  not included                   217.79
Lost Caregiver Days \3\..........  22.98                           61.50
Lost Leisure Productivity \4\....  not included                   162.98
Lost Productivity at Work........  not included                   126.29
----------------------------------
    Total........................  274.34                         844.24
------------------------------------------------------------------------
\1\ Assigned to 39.7% of the population not engaged in market work;
  assumes 40 hr. unpaid work week, valued at $6.23/hr in traditional COI
  and $12.46/hr in enhanced COI. Does not include lost unpaid work for
  employed people and may not include all unpaid work for people outside
  the paid labor force.
\2\ Includes child care and homemaking (to the extent not covered in
  lost unpaid work days above), time with family, and recreation for
  people within and outside the paid labor force, on days when subject
  is too sick to work.
\3\ Values lost work or leisure time for people caring for the ill.
  Traditional approach does not include lost leisure time. Detail may
  not calculate to totals due to independent rounding; Source: Appendix
  L in LT2ESWTR EA (USEPA 2005a)
\4\ Analogous to lost productivity at work. Includes reduced
  productivity in unpaid work and reduced enjoyment of recreation on
  days when subject is sick but engages in unpaid work or leisure
  activities anyway.

    The various loss categories were calculated as follows: Medical
costs are a weighted average across the three illness severity levels
of actual costs for doctor and emergency room visits, medication, and
hospital stays. Lost paid work represents missed work time of paid
employees, valued at the median pre-tax wage, plus benefits, of $20.82
hour. The average number of lost work hours per illness day is 3.4
(this assumes that 60 percent of the population is in the paid labor
force and the loss is averaged over 7 days). The weighted average
number of lost work days per case is 1.7 days. Medical costs and lost
work days reflect market transactions. Medical costs are always
included in COI estimates and lost work days are usually included in
COI estimates.
    In the traditional COI estimate, an equivalent amount of lost
unpaid work time was assigned to the 40 percent of the population that
are not in the paid labor force. This includes homemakers, students,
children, retires, and unemployed persons. This estimate attempts to
capture market-like work (e.g., homemaking, volunteer work) that is
unpaid. EPA did not attempt to calculate what percent of cases falls in
each of these five groups, or how many hours per week each group works,
but rather assumed an across-the-board 40 hour unpaid work week. For
this reason, it likely overstates the value of unpaid, market-like
work, but EPA does not have data on this. This time is valued at $6.23
per hour, which is one half the median post-tax wage (since work
performed by these groups is not taxed). This is also approximately the
median wage for paid household domestic labor.
    In the enhanced COI estimate, an estimate of lost unpaid work days
for people outside the paid labor force was made by assigning the value
of $12.46 per hour to the same number of unpaid work hours valued in
the traditional COI approach (i.e., 40 unpaid work hours per week).
Lost unpaid work for employed people and any unpaid labor beyond 40
hours per week for those not in the labor market is shown as lost
leisure time in Table VI.C-2 for the enhanced approach and is not
included in the traditional approach.
    In the enhanced approach, all time other than paid and market-like
work and sleep (8 hours per work day and 16 hours per non-work day) is
valued at the median after tax wage, or $12.46 per hour. This includes
lost unpaid personal work (e.g., chores, errands, housework) and
leisure time for people within and outside the paid labor force. The
average number of unpaid work hours per illness day is 2.3 (40 hours
per week averaged over 7 days x 40 percent of the population). Implicit
in this approach is that people would pay the same amount not to be
sick during their leisure time as they require to give up their leisure
time to work (i.e., the after tax wage). In reality, people might be
willing to pay either more than this amount (if they were very sick and
suffering a lot) or less than this amount (if they were not very sick
and still got some enjoyment out of activities such as resting,
reading, and watching TV), not to be sick. Multiplying 10.3 hours by
$12.46 gives a value of about $128 for a day of ``lost'' unpaid
personal work and leisure (i.e., lost utility of being sick). The
weighted average number of lost leisure days per case is the same as
the weighted average number of lost work days (1.7 days per case).

    In addition, for days when an individual is well enough to work but
is still experiencing symptoms, such as diarrhea, the enhanced estimate
also includes a 30 percent loss of work and leisure productivity, based
on a study of giardiasis illness (Harrington et al. 1985), which is
similar to cryptosporidiosis. Appendix P in the EA describes similar
productivity losses for other illnesses such as influenza (35%-73%
productivity losses). In the traditional COI analysis, productivity
losses are not included for either work or nonwork time. The weighted
average number of reduced productivity days per case, for both work and
leisure, is 1.3 days.
    EPA believes that losses in productivity and lost leisure time are
unquestionably present and that these categories have positive value;
consequently, the traditional COI estimate understates the true value
of these loss categories. EPA notes that these estimates should not be
regarded as upper and lower bounds. In particular, the enhanced COI
estimate may not fully incorporate the value of pain and suffering, as
people may be willing to pay more than $228 (the sum of the valuation
of lost work and leisure) to avoid a day of illness. The traditional
COI estimate may not be a lower bound because it includes a valuation
for a lost 40 hour work week for all persons not in the labor force,
including children and retirees. This may be an overstatement of lost
productivity for these groups, which would depend on the impact of such
things as missed school work or volunteer activities that may be
affected by illness.
    As with the avoided mortality valuation, the real wages used in the
COI estimates were increased by a real income growth factor that varies
by year, but is the equivalent of about 1.9 percent over the 20 year
period. This approach of adjusting for real income growth was
recommended by the SAB (USEPA 2000d) because the median real wage is
expected to grow each year (by approximately 1.9 percent).
Correspondingly, the real income growth factor of the COI estimates
increases by the equivalent of 1.9 percent per year (except for medical
costs, which are not directly tied to wages). This approach gives a
total COI valuation per case in 2010 of $306 (undiscounted) for the
traditional COI estimate and $985 (undiscounted) for the enhanced COI
estimate; the valuation in 2029 is $381 (undiscounted) for the
traditional COI estimate and $1,316 (undiscounted) for the enhanced COI
estimate. There is no difference in the methodology for calculating the
COI over this 20 year period of implementation; the change in valuation
is due to the underlying change in projected real wages.
    Table VI.C-3 summarizes the annual cases of cryptosporidiosis
illness and associated deaths avoided due to the LT2ESWTR proposal.
Today's rule, on average, is expected to reduce 89,375 to 1,459,126
illnesses and 20 to 314 deaths annually after full implementation
(range based on the ICRSSL, ICRSSM, and ICR data sets and model choice
for Cryptosporidium infectivity).
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    Tables VI.C-4a and VI.C-4b show the monetized present value of the
benefit for reductions in endemic cryptosporidiosis estimated to result
from the LT2ESWTR for the enhanced and traditional COI values,
respectively. Estimates are given for the ICR, ICRSSL, and ICRSSM
occurrence data sets and for the three infectivity models.
    With the enhanced COI and a 3 percent discount rate, the annual
present value of the mean benefit estimate ranges from $177 million to
$2.8 billion; at a 7 percent discount rate, the mean estimate ranges
from $144 million to $2.3 billion. With the traditional COI, the
corresponding mean benefit estimate at a 3 percent discount rate ranges
from $130 million to $2.0 billion; for a 7 percent discount rate, the
mean estimate ranges from $105 million to $1.7 billion. None of these
values include the unquantified and nonmonetized benefits listed in
Table VI.C-1.
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BILLING CODE 6560-50-C
    a. Filtered PWSs. Benefits to the approximately 168 million people
served by filtered surface water and GWUDI PWSs range from 34,000 to
702,000 reduction in mean annual cases of endemic illness based on
three infectivity models and ICRSSL, ICRSSM, and ICR data sets. In
addition, premature mortality is expected to be reduced by an average
of 6 to 116 deaths annually.
    b. Unfiltered PWSs. The 10 million people served by unfiltered
surface water or GWUDI PWSs will see a significant reduction in
cryptosporidiosis as a result of the LT2ESWTR. In this population, the
rule is expected to reduce approximately 55,000 to 758,000 cases of
illness and 14 to 197 premature deaths annually.
    For unfiltered PWSs, only the ICR data set is used to directly
calculate illness reduction because it is the only data set that
includes sufficient information on unfiltered PWSs. Illness reduction
in unfiltered PWSs was estimated for the ICRSSL and ICRSSM

data sets by multiplying the ICR unfiltered PWS result by the ratio,
for the quantity estimated, between filtered PWS results from the
supplemental survey data set (SSM or SSL) and filtered PWS results from
the ICR.
3. Timing of Benefits Accrual (latency)
    In previous rulemakings, some commenters have argued that the
Agency should consider an assumed time lag or latency period in its
benefits calculations. The Agency has not conducted a latency analysis
for this rule because cryptosporidiosis is an acute illness; therefore,
very little time elapses between exposure, illness, and mortality.
However, EPA does account for benefits and costs that occur in future
years by converting these to present value estimates.

D. What Are the Costs of the LT2ESWTR?

    In order to estimate the costs of today's rule, the Agency
considered impacts on PWSs and on States (including territories and EPA
implementation in non-primacy States). Summary information on these
costs follows, with more detailed information in chapter 6 of the
LT2ESWTR EA (USEPA 2005a). A detailed discussion of the requirements of
today's rule is located in section IV of this preamble.
1. Total Annualized Present Value Costs
    Tables VI.D-1 summarizes the annualized present value cost
estimates for the LT2ESWTR at 3 percent and 7 percent discount rates.
The mean annualized present value costs of the LT2ESWTR are estimated
to range from approximately $93 to $133 million using a 3 percent
discount rate and $107 to $150 million using a 7 percent discount rate.
This range in mean cost estimates is associated with the different
Cryptosporidium occurrence data sets. In addition to mean estimates of
costs, the Agency calculated 90 percent confidence bounds by
considering the uncertainty in Cryptosporidium occurrence estimates and
the uncertainty around the mean unit technology costs (USEPA 2005a).
    PWSs will incur approximately 99 percent of the rule's total
annualized present value costs. States incur the remaining rule costs.
Table VI.D-2 shows the undiscounted initial capital and one-time costs
broken out by rule component. A comparison of annualized present value
costs among the rule alternatives considered by the Agency is located
in section VI.F of this preamble.
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[GRAPHIC] [TIFF OMITTED] TR05JA06.004

BILLING CODE 6560-50-C

2. PWS Costs
    Table VI.D-3 shows the number of filtered and unfiltered PWSs that
will incur costs by rule provision. All PWSs that treat surface water
or GWUDI (i.e., nonpurchased PWSs) will incur one-time costs that
include time for staff training on rule requirements. PWSs will incur
monitoring costs to assess source water Cryptosporidium levels, though
monitoring requirements vary by PWS size (large vs. small) and PWS type
(filtered vs. unfiltered). Some PWSs will incur costs for additional
Cryptosporidium treatment, where required, and for covering or treating
uncovered finished water reservoirs.
[GRAPHIC] [TIFF OMITTED] TR05JA06.005

    a. Source water monitoring costs. Source water monitoring costs are
structured on a per-plant basis. There are three types of monitoring
that plants may be required to conduct--turbidity, E. coli, and
Cryptosporidium. Source water turbidity is a common water quality
parameter used for plant operational control. Also, to meet SWTR,
LT1ESWTR, and IESWTR requirements, most PWSs have turbidity analytical
equipment in-house and operators are experienced with turbidity
measurement. Thus, EPA assumes that the incremental turbidity
monitoring burden associated with the LT2ESWTR is negligible.
    Filtered plants in small PWSs initially will be required to conduct
1 year of biweekly E. coli source water monitoring. These plants will
be required to monitor for Cryptosporidium if E. coli levels exceed 10
E. coli/100 mL for lakes and reservoir sources or 50 E. coli/100 mL for
flowing stream sources. EPA estimated the percent of small plants that
would be triggered into Cryptosporidium monitoring as being equal to
the percent of large plants that would fall into any bin requiring
additional treatment.
    Estimates of laboratory fees, shipping costs, labor hours for
sample collection, and hours for reporting results were used to predict
PWS costs for initial source water monitoring under the LT2ESWTR. Table
VI.D-4 summarizes the present value of monitoring costs for initial bin
classification. Total present value monitoring costs for initial bin
classification range from $45 million to $59 million depending on the
occurrence data set and discount rate. Appendix D of the LT2ESWTR EA
provides a full explanation of how these costs were developed (USEPA
2005a).
    b. Filtered PWSs treatment costs. The Agency calculated treatment
costs by estimating the number of plants that will add treatment
technologies and coupling these estimates with unit costs ($/plant) of
the selected technologies. Table VI.D-5 shows the number of plants
estimated to select different treatment technologies; Table VI.D-6
summarizes the present value treatment costs and annualized present
value costs for both filtered and unfiltered PWSs.

[GRAPHIC] [TIFF OMITTED] TR05JA06.006

    To estimate the number of filtered plants that would select a
particular treatment technology, EPA followed a two step process.
First, the number of plants that will be assigned to treatment bins
requiring additional treatment was estimated. Second, the treatment
technologies that plants will choose to meet these requirements was
estimated using a ``least-cost decision tree.'' In this estimate, EPA
assumed that PWSs will select the least expensive technology or
combination of technologies to meet the log removal requirements of a
given treatment bin. Technology selections were constrained by maximum
use percentages, which recognize that some plants will not be able to
implement certain technologies because of site-specific conditions. In
addition, certain potentially lower cost components of the microbial
toolbox, such as changes to the plant intake, were not included because
EPA lacked data to estimate the number of plants that could select it.
These limitations on technology use may result in an overestimate of
costs. An in-depth discussion of the technology selection methodology
and unit cost estimates can be found in Appendices E and F of the
LT2ESWTR EA (USEPA 2005a).
[GRAPHIC] [TIFF OMITTED] TR05JA06.007

    c. Unfiltered PWSs treatment costs. The LT2ESWTR requires all
unfiltered PWSs to achieve 2-log of inactivation if their mean source
water Cryptosporidium concentration is less than or equal to 0.01
oocysts/L and 3-log of inactivation if it is greater than 0.01 oocysts/
L. For most PWSs, UV appears to be the least expensive technology that
can achieve these levels of Cryptosporidium inactivation, and EPA
expects UV to be widely used by unfiltered PWSs to meet today's rule
requirements. However, as with filtered PWSs, EPA estimated that a
small percentage of plants would elect to install a technology more
expensive than UV due to the configuration of

existing equipment or other factors. Ozone is the next least expensive
technology that will meet the inactivation requirements for some PWSs
and EPA estimated that it will be used by plants that do not use UV.
    All unfiltered PWSs must meet requirements of the LT2ESWTR;
therefore, 100 percent of unfiltered PWSs are estimated to add
technology. This assumes that no unfiltered PWSs currently use these
additional treatment technologies. For this cost analysis, EPA assumed
that all very small unfiltered PWSs will use UV; for all other
unfiltered PWS sizes, EPA estimated that 90 percent will install UV and
10 percent will add ozone. Treatment costs for unfiltered PWSs are
included in Table VI.D-6.
[GRAPHIC] [TIFF OMITTED] TR05JA06.008

    d. Uncovered finished water storage facilities. As part of the
LT2ESWTR, PWSs with uncovered finished water storage facilities must
either cover the storage facility or treat the discharge to achieve
inactivation and/or removal of at least 2-log Cryptosporidium, 3-log
Giardia lamblia, and 4-log viruses. To develop national cost estimates
for PWSs to comply with these provisions, unit costs for each
compliance alternative and the percentage of PWSs selecting each
alternative were estimated for the inventory of uncovered finished
water storage facilities. From a recent survey of EPA Regions, EPA
estimates that there are currently 81 uncovered finished water storage
facilities for which PWSs must take steps to comply with the LT2ESWTR.
A full description of the unit costs and other assumptions used in this
analysis is presented in Chapter 6 and Appendix I of the LT2ESWTR EA
(USEPA 2005a).
    To comply with the treatment requirements, EPA determined that the
least-cost treatment option is a combination of chlorine and UV. For
PWSs with uncovered storage facility capacities of 5 million gallons
(MG) or less, covering the storage facilities is the least expensive
alternative. Although disinfection is the least expensive alternative
for the remaining PWSs, the ability of a PWS to use booster
chlorination depends on their current residual disinfectant type.
Somewhat less than half of all surface water PWSs are predicted to use
chloramination following implementation of the Stage 2 DBPR. Adding
chlorine to water that has been treated with chloramines is not a
feasible alternative; therefore, the fraction of PWSs projected to add
UV and booster chlorination to the effluent from the uncovered storage
facility was estimated at 50 percent, with the remaining 50 percent
projected to add covers.
    Table VI.D-7 summarizes total annualized present value costs for
the uncovered finished water storage facility requirements using both 3
and 7 percent discount rates. EPA estimates the total annualized
present value cost for covering or treating the water from uncovered
finished water storage facilities to be approximately $10 million at a
3 percent discount rate and $13 million at a 7 percent discount rate.

[GRAPHIC] [TIFF OMITTED] TR05JA06.009

    e. Future monitoring costs. Six years after initial bin
classification, filtered and unfiltered PWSs must conduct a second
round of monitoring to assess whether source water Cryptosporidium
levels have changed significantly. EPA will evaluate new analytical
methods and surrogate indicators of microbial water quality in the
interim. While the costs of monitoring are likely to change in the 9
years following rule promulgation, it is difficult to predict how they
will change. In the absence of any other information, EPA assumed that
the laboratory costs will be the same as for the initial monitoring.
    All PWSs that conducted initial monitoring were assumed to conduct
the second round of monitoring, except for those PWSs that installed
treatment that achieves a total of 5.5-log or greater treatment for
Cryptosporidium as a result of the rule. These PWSs are exempt from
monitoring under the LT2ESWTR. EPA estimates that the cost of the
second round of source water monitoring will range from $21 million to
$36 million, depending on the occurrence data set and discount rate
used in the estimate. Appendix D of the EA provides further details
(USEPA 2005a).
    f. Sensitivity analysis-influent bromide levels on technology
selection for filtered plants. One concern with the ICR data set is
that it may not reflect influent bromide levels in some PWSs during
droughts. High influent bromide levels (the precursor for bromate
formation) limits ozone use because some PWSs would not be able to meet
the MCL for bromate. EPA conducted a sensitivity analysis to estimate
the impact that higher influent bromide levels would have on technology
decisions. The sensitivity analysis assumed influent bromide
concentrations of 50 parts per billion (ppb) above the ICR
concentrations. Results of the analysis indicate that this higher
bromide level has a minimal impact on costs.
3. State/Primacy Agency Costs
    EPA estimates that States (including primacy agencies) will incur
an annualized present value cost of $1.1 to 1.2 million using a 3
percent discount rate and $1.4 million at 7 percent. State
implementation activities include regulation adoption, program
implementation, training State staff, training PWS staff, providing
technical assistance to PWSs, and updating management systems. To
estimate implementation costs to States, the number of full-time
employees (FTEs) per activity is multiplied by the number of labor
hours per FTE, the cost per labor hour, and the number of States and
Territories.
    In addition to implementation costs, States will also incur costs
associated with managing monitoring data. Because EPA will directly
manage reporting, approval, and analysis of results from the initial
round of monitoring by large PWSs (serving at least 10,000 people),
States are not predicted to incur costs for these activities. States
will, however, incur costs associated with small PWS monitoring. This
is a result of the later start of small PWS monitoring, which will mean
that some States will assume primacy for small PWS monitoring. In
addition, States will review the second round of monitoring results.
States will also incur costs for reviewing technology compliance data
and consulting with PWSs regarding disinfection benchmarking (for PWSs
that change their disinfection procedures to comply with today's rule).
Appendix D of the LT2ESWTR EA provides more information about the State
cost analysis (USEPA 2005a).
4. Non-Quantified Costs
    EPA has quantified all the major costs for this rule and has
provided uncertainty analyses to bound the over or underestimates in
the costs. There are some costs that EPA has not quantified, however,
because of lack of data. For example, some PWSs may merge with
neighboring PWSs to comply with this rule. Such changes have both costs
(legal fees and connecting infrastructure) and benefits (economies of
scale). Likewise, PWSs would incur costs for procuring a new source of
water that may result in lower overall treatment costs.
    In addition, the Agency was unable to predict the usage or estimate
the costs of several options in the microbial toolbox. These options
include intake management and demonstrations of performance. They have
not been included in the quantified analysis because data are not
available to estimate the number of PWSs that may use these toolbox
options to comply with the LT2ESWTR. Not including these generally
lower-cost options may result in overestimation of costs.

E. What Are the Household Costs of the LT2ESWTR?

    Another way to assess a rule's impact is to consider how it may
impact residential water bills. This analysis considers the potential
increase in a household's water bill if a CWS passed the entire cost
increase resulting from this rule on to its customers. This serves as a
tool to gauge potential impacts and should not be construed as precise
estimates of potential changes to individual water bills.
    Included in this analysis are all PWS costs, including rule
implementation, initial and future monitoring for bin classification,
additional Cryptosporidium treatment, and treating

or covering uncovered finished water storage facilities. Costs for
Cryptosporidium monitoring by small PWSs, additional Cryptosporidium
treatment, and uncovered finished water storage facilities are assigned
only to the subset of PWSs expected to incur them. Although
implementation and monitoring represent relatively small, one-time
costs, they have been included in the analysis to provide a complete
distribution of the potential household cost. A detailed description of
the derivation of household costs is in Chapter 6 and Appendix J of the
LT2ESTWR EA (USEPA 2005a).
    For PWSs that purchase treated water (i.e., purchased PWSs) from
larger nonpurchased PWSs, the households costs are calculated based on
the unit treatment costs of the larger PWS but included in the
distribution for the size category of the purchased PWS. Households
costs for these purchased PWSs are based on the household usage rates
appropriate for the retail PWS and not the PWS selling (wholesaling)
the water. This approach for purchased PWSs reflects the fact that
although they will not face increased costs from adding their own
treatment, whatever costs the wholesale PWS incurs will likely be
passed on as higher water costs.
    Table VI.E-1 shows the results of the household cost analysis. In
addition to mean and median estimates, EPA calculated the 90th and the
95th percentiles. EPA estimates that all households served by surface
and GWUDI sources will face some increase in household costs due to
implementation of the LT2ESWTR. Of all the households subject to the
rule, from 22 to 41 percent are projected to incur costs for adding
treatment, depending on the Cryptosporidium occurrence data set used.
    Approximately 92 percent of the households potentially subject to
the rule are served by PWSs serving at least 10,000 people and 99.8
percent are served by PWSs serving at least 500 people; these PWSs
experience the lowest increases in costs due to significant economies
of scale. Over 95 percent of all households are estimated to face an
annual cost increase of less than $12. Households served by small PWSs
that install advanced technologies will face the greatest increases in
annual costs. EPA expects that the model's projections for these PWSs
are, in some cases, overstated. Some PWSs are likely to find
alternative treatment techniques such as other toolbox options not
included in this analysis, or sources of water (ground water, purchased
water, or consolidating with another PWS) that would be less costly
than installing more expensive treatment technologies.
[GRAPHIC] [TIFF OMITTED] TR05JA06.010

F. What Are the Incremental Costs and Benefits of the LT2ESWTR?

    Incremental costs and benefits are those that are incurred or
realized in reducing Cryptosporidium exposures from one regulatory
alternative to the next. Estimates of incremental costs and benefits
are useful in considering the economic efficiency of different
regulatory alternatives evaluated by EPA. Generally, the goal of an
incremental analysis is to identify the most efficient regulatory
alternative. However, this analysis is incomplete because some benefits
from this rule are unquantified and not monetized. Incremental analyses
should consider both quantified and unquantified (where possible)
benefits and costs.
    Usually an incremental analysis implies increasing levels of
stringency along a single parameter, with each alternative providing
all the protection of the previous alternative, plus additional
protection. However, the regulatory alternatives evaluated for the
LT2ESWTR vary by multiple parameters (e.g., treatment bin boundaries,
treatment requirements). The comparison between any two alternatives
is, therefore, between two separate sets of benefits, in the sense that
they may be distributed to somewhat different population groups.
    The regulatory alternatives, however, do achieve increasing levels
of benefits at increasing levels of costs. As a result, displaying
incremental net benefits from the baseline and alternative to
alternative is possible. Tables VI.F-1a and VI.F-1b show incremental
costs, benefits, and net benefits for the four regulatory alternatives,
A1-A4, shown in Table VI.A-1, using the enhanced and traditional COI,
respectively. All values are annualized present values expressed in
Year 2003 dollars. The displayed values are the mean estimates for each
occurrence distribution and infectivity model.
    With the enhanced COI, incremental costs are generally closest to
incremental benefits for A2, a more stringent alternative than A3,
which is today's final rule. For the traditional COI, incremental costs
most closely equal incremental benefits for A3 under the majority of
conditions evaluated.

G. Are There Benefits From the Reduction of Co-Occurring Contaminants?

    While the quantified and monetized benefits for the LT2ESWTR
includes only reductions in illness and mortality attributable to
Cryptosporidium, today's rule will reduce exposure to and disease from
other microbial pathogens and, in some cases, chemical contaminants.

[GRAPHIC] [TIFF OMITTED] TR05JA06.011

[GRAPHIC] [TIFF OMITTED] TR05JA06.012

    All of the options in the microbial toolbox that PWSs will
implement to comply with today's rule will also reduce levels of other
microbial pathogens. For example, watershed control programs and intake
relocation

will cut overall pathogen levels by reducing fecal contamination in the
source water. Membrane, bag, and cartridge filters will remove
pathogenic protozoa like Giardia lamblia that are similar in size to or
larger than Cryptosporidium. Lowering finished water turbidity from
conventional and direct filtration will improve removal of pathogens
across a broad size range, including viruses, bacteria, and protozoa.
Inactivation technologies like ozone and UV are highly effective
against a large number of different pathogen types.
    Some membrane technologies that PWSs may install to comply with the
LT2ESWTR can also reduce or eliminate chemical contaminants including
arsenic, DBPs, and atrazine. The use of UV for inactivation of
Cryptosporidium may reduce the chlorine dosage that some PWSs must
apply, which can reduce levels of DBPs. EPA has recently finalized a
rule to further control arsenic levels in drinking water and is
concurrently establishing the Stage 2 DBPR to address DBP control.
    The extent to which the LT2ESWTR can reduce the overall risk from
other contaminants has not been quantitatively evaluated because EPA
lacks sufficient data on the co-occurrence among Cryptosporidium and
other microbial pathogens and contaminants. Further, due to the
difficulties in establishing which PWSs would have multiple problems,
such as microbial contamination, arsenic, and DBPs or any combination
of the three, no estimate was made of the potential cost savings from
addressing more than one contaminant simultaneously.

H. Are There Increased Risks From Other Contaminants?

    It is unlikely that the LT2ESWTR will result in a significant
increase in risk from other contaminants for most PWSs. Many of the
options that PWSs will select to comply with the LT2ESWTR, such as UV,
additional or improved filtration, and watershed control, do not form
DBPs. Ozone, another technology that is effective against
Cryptosporidium, does form DBPs (e.g., bromate). However, bromate is
currently regulated under the Stage 1 DBPR, and PWSs will have to
comply with this regulation if they implement ozone to meet the
LT2ESWTR.

I. What Are the Effects of the Contaminant on the General Population
and Groups Within the General Populations That Are Identified as Likely
To be at Greater Risk of Adverse Health Effects?

    Section III of this preamble discusses the health effects
associated with Cryptosporidium on the general population as well as
the effects on other sensitive sub-populations. In addition, health
effects associated with children and pregnant women are discussed in
greater detail in section VII.G of this preamble.

J. What Are the Uncertainties in the Risk, Benefit, and Cost Estimates
for the LT2ESWTR?

    For today's final rule, EPA has modeled the current baseline risk
from Cryptosporidium exposure through drinking water, along with the
reduction in risk and the cost for various rule alternatives. There is
uncertainty in the risk calculation, the benefit estimates, the cost
estimates, and the interaction with other regulations. The LT2ESWTR EA
has an extensive discussion of relevant uncertainties (USEPA 2005a),
and a brief summary of the major uncertainties follows.
    In regard to the risk estimates, the most significant areas of
uncertainty are Cryptosporidium occurrence, treatment, and infectivity.
Among the three available occurrence data sets, the ICR plant-mean data
were higher than the ICRSSM or ICRSSL plant-mean data at the 90th
percentile. The reasons for these differing results are not well
understood but may stem from year-to-year variation in occurrence and
differences in the sampling and measurement methods employed. The
ICRSSM and ICRSSL data sets use a newer, more reliable sampling method
but include fewer plants and a shorter time frame. Additional
uncertainty is associated with estimating finished water occurrence
because the analysis is based on estimates of treatment plant
performance in removing Cryptosporidium.
    EPA has addressed some of the uncertainty in occurrence by
evaluating benefits and costs for regulatory alternatives with each
Cryptosporidium data set. Further, in the 2-dimensional Monte Carlo
simulation models used to estimate risk, key parameters like occurrence
and treatment efficiency are treated as both variable and uncertain.
This approach is intended to account for the limitations in available
data and the recognized variability in these parameters among PWSs.
    EPA has also considered occurrence data from additional sources.
For example, the LT2ESWTR EA discusses a study of infectious
Cryptosporidium in the finished water of 82 filtration plants by
Aboytes et.al, 2004. The mean level of infectious Cryptosporidium
measured in this study is higher than EPA has estimated using the ICR,
ICRSSM, or ICRSSL data sets. This result suggests that Cryptosporidium
occurrence at these plants may have exceeded levels during the ICR and
ICRSS surveys or that EPA may have overestimated the efficiency of
treatment plants in removing Cryptosporidium.
    In regard to Cryptosporidium infectivity, EPA evaluated data from
human feeding studies conducted with different Cryptosporidium
isolates. The measured infectivity of these isolates varied widely,
however, and how well these isolates represent Cryptosporidium that
causes disease in PWSs is uncertain. In addition, extrapolating from
the higher Cryptosporidium dosing levels used in the human feeding
studies to the exposure levels typical for drinking water (e.g., one
oocyst) is uncertain. Another source of uncertainty is differences that
exist among populations groups, such as individuals that are more
sensitive (e.g., children, immunocompromised) or less sensitive
(previously infected adults).
    EPA accounted for some of this uncertainty in infectivity by
treating the human feeding study results for different Cryptosporidium
isolates as random samples from a larger and unknown environmental
distribution of Cryptosporidium infectivity. EPA used a variety of
models for this analysis, as recommended by the SAB, and presents
results for a range of models to account for uncertainty in model
selection. In addition, limited data on levels of Cryptosporidium in
the 1993 Milwaukee outbreak and associated disease incidence suggest
that the infectivity of the Cryptosporidium responsible for that
outbreak is within the range EPA has estimated for the risk assessment
in today's rule.
    Unquantified benefits from the reduction of co-occurring microbial
pathogens, as described earlier, are a significant source of
uncertainty in the estimate of benefits for the LT2ESWTR. EPA is also
uncertain about the monetization of avoided disease from
Cryptosporidium and has addressed this uncertainty through the use of
both traditional and enhanced COI values for benefits estimates.
    While all of the significant costs of today's rule have been
identified by

EPA, there are uncertainties in the estimates. Occurrence is the most
significant source of uncertainty in costs, and EPA has attempted to
account for this uncertainty through the use of different occurrence
data sets and Monte Carlo modeling as described previously. EPA has
also estimated uncertainty in unit process costs for treatment
technologies. In addition, the cost assessment for today's rule
includes sensitivity analyses, such an assessment of the impact of
influent bromide levels on technology selection. Chapter 6 of the
LT2ESWTR EA provides a fuller description of uncertainties in the cost
estimates (USEPA 2005a).
    Last, EPA has recently finalized or is currently finalizing new
regulations for arsenic, radon, Cryptosporidium in small surface water
PWSs, filter backwash recycling, microbial pathogens in PWSs using
ground water, and DBPs. These rules may have overlapping impacts on
some PWSs, but the extent is not possible to estimate due to lack of
information on co-occurrence. However, PWSs may choose treatment
technologies that will address multiple contaminants. Therefore, while
the total cost impact of these drinking water rules is uncertain, it is
most likely less than the estimated total cost of all individual rules
combined.

K. What Is the Benefit/Cost Determination for the LT2ESWTR?

    The Agency has determined that the benefits of the LT2ESWTR justify
the costs. As discussed in section VII.C, the rule provides a large
reduction in endemic cryptosporidiosis illness and mortalities. More
stringent alternatives provide greater reductions but at higher costs.
Alternative A1 provides the greatest overall reduction in illnesses and
mortalities but the incremental benefits between this option and
alternative A3 (today's final rule) are relatively small while the
incremental costs are significant. In addition, today's rule, unlike
alternative A1, specifically targets those PWSs whose source water
requires higher levels of treatment.
    Tables VI.K-1a and VI.K-1b present net benefits for the four
regulatory alternatives that were evaluated. Generally, analysis of net
benefits is used to identify alternatives where benefits exceed costs,
as well as the alternative that maximizes net benefits. However, as
with the analysis of incremental net benefits discussed previously, the
usefulness of this analysis in evaluating regulatory alternatives for
the LT2ESWTR is somewhat limited because many benefits from this rule
are unquantified and nonmonetized. Analyses of net benefits should
consider both quantified and unquantified (where possible) benefits and
costs.
    Also, as noted earlier, the regulatory alternatives considered for
the LT2ESWTR vary both in the population that experiences benefits and
costs (i.e., treatment bin boundaries) and the magnitude of the
benefits and costs (i.e., treatment requirements). Consequently, the
more stringent regulatory alternatives provide benefits to population
groups that do not experience any benefit under less stringent
alternatives.
    As shown by Tables VI.K-1a and VI.K-1b, net benefits are positive
for all four regulatory alternatives evaluated under most occurrence
and discount rate scenarios. With both the enhanced COI and traditional
COI, net benefits are highest for the alternative A3, which is today's
final rule, under the majority of occurrence distributions and discount
rates evaluated.
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[GRAPHIC] [TIFF OMITTED] TR05JA06.014

    In addition to the net benefits of the LT2ESWTR, the Agency used
several other techniques to compare costs and benefits. For example,
EPA calculated the cost of the rule per case avoided. Tables VI.K-2a, b
and c show both the cost of the rule per illness avoided and cost of
the rule per death avoided. This cost effectiveness measure is another
way of examining the benefits and costs of the rule but should not be
used to compare alternatives because an alternative with the lowest
cost per illness/death avoided may not result in the highest net
benefits. With the exception of alternative A1, the rule options look
favorable when the cost per case avoided is compared to both the
weighted cost of cryptosporidiosis illness ($844 and $274 for the two
COI approaches) and the mean value of a statistical death avoided--
approximately $7 million dollars. Additional information about this
analysis and other methods of comparing benefits and costs can be found
in chapter 8 of the LT2ESWTR EA (USEPA 2005a).

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L. Summary of Major Comments

    EPA received significant public comment on the analysis of benefits
and costs of the August 11, 2003 proposed LT2ESWTR in the following
areas: Cryptosporidium occurrence, drinking water consumption,
Cryptosporidium infectivity (i.e., dose-response), and valuation of
benefits. The following discussion summarizes public comment in these
areas and EPA's responses.
1. Cryptosporidium Occurrence
    With respect to the analysis of Cryptosporidium occurrence, two
areas that received significant public comment are the quality of the
ICR and ICRSS data sets (i.e., whether the estimates derived from them
should be regarded as equally plausible) and the treatment of samples
in which no Cryptosporidium is detected (i.e., observed zeros).
    a. Quality of the ICR and ICRSS data sets. As noted earlier, the
ICR, ICRSSM, and ICRSSL data sets differ significantly in the high
concentration portion of the occurrence distribution (e.g., 90th
percentile). While the measurement method employed in the ICRSS had
higher recovery and less variable volumes assayed, the ICR produced a
much greater number of assays and source waters sampled. Lacking a
technical basis to conclude that one data set provides a better
estimate, EPA conducted separate analyses of costs and benefits for all
three data sets. EPA requested comment on this approach.
    The majority of commenters on this issue supported EPA's approach
of analyzing the three data sets separately to represent uncertainty
about occurrence. Two commenters suggested that the ICR data would be
more reliable for estimating national occurrence due to the larger
number of samples, while two others viewed the ICRSS data as more
reliable due to the improved analytical method. No commenters provided
a technical analysis indicating that one data set is more accurate.
Given these comments, EPA has retained the approach of analyzing costs
and benefits separately for each occurrence data set in today's final
rule.
    b. Treatment of observed zeros. One commenter remarked that the
majority of samples in which no oocysts were detected (i.e., observed
zeros) likely contained no oocysts in the volume assayed. This
commenter was concerned with a parameter in EPA's occurrence analysis
model for ``true zero,'' which characterizes the likelihood that a
source water is entirely free of Cryptosporidium at all times. In EPA's
model, the true zero parameter was assigned a value of 0.1 percent. As
described in USEPA (2005b), EPA based this assumption on the finding
that intensive sampling of surface waters usually detects
Cryptosporidium, even in protected watersheds. The commenter concluded,
however, that the true zero parameter resulted in the model assigning a
value of at least 1 oocyst to 99.9 percent of samples.
    EPA responds that the true zero parameter in the occurrence
analysis model does not operate in this way. While the model is set-up
to estimate mean source water concentrations and not the concentrations
in individual volumes assayed, the model recognizes that the majority
of samples in the ICR and ICRSS contained no oocysts. The model does
assume that few, if any, of the source waters sampled in these surveys
never contained a single oocyst (the meaning of the true zero
parameter). EPA has clarified the definition of the true zero parameter
in USEPA (2005b). EPA has also conducted a sensitivity analysis in
which the true zero parameter was varied from values of 0 to 50
percent, with little effect on estimates of risk, benefit, and cost for
today's rule.
2. Drinking Water Consumption
    Two commenters were concerned with the distribution for drinking
water consumption that EPA used in the proposed LT2ESWTR. This
distribution, which was based on a 1994-1996 survey by the United
States Department of Agriculture (USDA), reflects water consumption
from all sources. Commenters recommended two modifications to this
approach: (1) Adjust the distribution to account for factors like
bottled water and boiled water use; and (2) use an alternative
distribution from the USDA survey that reflects consumption of
community water system (CWS) water only.

    In response, EPA agrees that the distribution should be adjusted to
remove consumption attributable to bottled water. For the consumption
distribution in today's final rule, EPA subtracted bottled water usage,
based on information in the USDA survey, which had the effect of
reducing consumption by approximately 14 percent in comparison to the
proposal. EPA does not have information on the effectiveness of heating
water to make coffee or tea for inactivating Cryptosporidium and has
not modified the consumption distribution on this basis.
    EPA continues to believe that the USDA distribution for consumption
of water from all sources, minus bottled water consumption, provides
the best available estimate for consumption of water from CWSs for
people served by CWSs. The USDA distribution for consumption of CWS
water only, which a commenter recommended, includes people not served
by CWSs (e.g., people with private wells). Inclusion these individuals
has the effect of underestimating the consumption of CWS water for
people served by CWSs in this distribution. In contrast, the
distribution for consumption of water from all sources includes people
not served by CWSs and the sources those people use (e.g., private
wells). This avoids the problem of underestimating consumption for
individuals served by CWS. Accordingly, EPA has retained the use of
this distribution in today's final rule, with the adjustment stated
previously for bottled water consumption.
3. Cryptosporidium Infectivity
    In regard to Cryptosporidium infectivity (i.e., dose-response
assessment), EPA received significant comment on limitations in the
human feeding studies (e.g. representativeness of Cryptosporidium
isolates used in the studies, numbers of subjects) and uncertainty in
extrapolating from high study doses to low drinking water doses. EPA
believes that the statistical analysis of dose-response data, as
described in USEPA (2005a), properly accounted for these limitations
and uncertainties.
    The statistical models used by EPA treated the isolates studied as
a random sample from a larger population of environmental isolates,
treated the subjects studied as a random sample from the larger
population of healthy individuals, and treated each individual's
outcome as a chance event, where the infection probability is a
function of the challenge dose. Collectively, these uncertainties
contributed to the significant uncertainty in EPA's estimate of the
likelihood of infection given one oocyst ingested.
    Since the LT2ESWTR proposal, EPA has reviewed results from
additional human feeding studies with Cryptosporidium isolates and
analyzed data from these and the feeding studies considered for the
proposal with additional dose-response models (USEPA 2005a). As
described in Chapter 5 and Appendix N of the LT2ESWTR EA, the
infectivity estimates from the proposal are near the middle of the
range of estimates derived with the additional feeding study data and
dose-response models. Further, the mean estimates from these new
analyses fall within the 90th percentile uncertainty bounds for
infectivity estimates from the proposal (USEPA 2005a). Consequently,
EPA believes that the infectivity estimates from the additional feeding
study data and dose-response models are consistent with and supportive
of the estimates of infectivity from the proposal. Further, EPA's
estimates of infectivity are consistent with data on the infectivity of
Cryptosporidium in the 1993 Milwaukee outbreak (USEPA 2005a).
4. Valuation of Benefits
    In the area of benefits valuation, EPA received significant public
comment on the valuation of morbidity, valuation of lost time under the
Enhanced COI approach, and unquantified benefits.
    a. Valuation of morbidity. EPA received a comment that endemic
cases that do not show up in public health surveillance data may be too
mild (and perhaps even asymptomatic) to be economically significant.
EPA believes endemic cases are significant in terms of public health
risk and economic impacts. As discussed earlier, only a small fraction
of the millions of cases of gastrointestinal illnesses are traced to a
specific illness (such as cryptosporidiosis); yet endemic disease
clearly exists and those illnesses, even if mild, have public health
consequences and economic impacts (e.g., missed work). For example, the
benefits model in the EA assumes that 88 percent of all cases are mild,
and yet those illnesses represent significant impacts nationally.
Further, the risk assessment model separately computes infections and
illnesses. Thus, asymptomatic infections are excluded; only avoided
illnesses are assigned monetary benefits.
    b. Valuation of lost time under the enhanced cost of illness (COI)
approach. One commenter extensively questioned the approach used to
value lost leisure and nonwork time under the Enhanced COI approach,
noting concerns about the relationship of the approach to standard
economics practices, the plausibility of the resulting values, and the
extent of peer review. The following discussion summarizes EPA's
responses on these issues.
    As discussed in detail in the EA (USEPA 2005a), EPA recognizes that
the preferred approach for valuing health risk reductions is to rely on
estimates of individual willingness to pay (WTP). In the absence of
suitable WTP estimates, analysts often rely on approaches similar to
the Traditional COI approach used for this rule, as noted by the
commenter. However, empirical research as well as theoretic concerns
suggest that these types of COI approaches will generally understate
true WTP.
    EPA designed the Enhanced COI approach to correct for one potential
source of understatement--the impact of illness on unpaid work and
leisure time. While the Enhanced COI approach is innovative, it is
rooted in standard welfare economic theory and builds on approaches
used to value time in numerous studies in the labor, transportation,
recreation, and health economics literature. The commenter is
concerned, however, that the Enhanced COI approach values nonwork time
at a higher rate than many recreational studies, several of which value
travel time at one-third of the wage rate. EPA's extensive review of
the recreational literature suggests, however, that there is no
consensus regarding the value of travel time, as discussed in the
Appendix P of the EA (USEPA 2005a). In addition, travel has both
pleasant and unpleasant aspects and hence may be valued less than other
leisure activities, many of which may be valued at a rate higher than
foregone wages.
    To test the plausibility of the results, the commenter compares the
value of a ``lifetime case'' of cryptosporidiosis to the value of
statistical life (VSL) and suggests that the results (which show that
such a case would be roughly 70 percent of VSL) are improbably high.
However, EPA believes that this comparison is seriously flawed. There
is no generally accepted standard for determining whether values for
nonfatal risk reductions are ``reasonable'' compared to values for
fatal risk reductions. In addition, the calculation of the value of a
lifetime case of cryptosporidiosis contains several computational
errors, and represents the loss of all waking time (not just losses
attributable to cryptosporidiosis) and so is seriously overstated.
Perhaps most important, the approach used to value

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[[Continued from page 752]]

time losses in the Enhanced COI estimate is appropriate only for
marginal changes in time use; it is not appropriate for the types of
lifetime changes considered in the comparison.
    The Enhanced COI estimates are based on an approach developed in
the EPA report, Valuing Time Losses Due to Illness under the 1996
Amendments to the Safe Drinking Water Act (USEPA 2005e). This report
has been subject to two rounds of independent peer review. In
conclusion, EPA believes that including the Enhanced COI in conjunction
with the Traditional COI is justified theoretically and that including
both measures increases EPA's ability to understand the impacts of the
rule.
VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866, [58 FR 51735, (October 4, 1993)] the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or Tribal governments or
communities;
    (2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
    (4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action''
because it may have an annual effect on the economy of $100 million or
more (estimated annual costs are $93 to 133 million and $107 to 150
million at 3 and 7 percent discount rates, respectively). As such, this
action was submitted to OMB for review. Changes made in response to OMB
suggestions or recommendations are documented in the public record.

B. Paperwork Reduction Act

    The Office of Management and Budget (OMB) has approved the
information collection requirements contained in this rule under the
provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and
has assigned OMB control number 2040-0266.
    The information collected as a result of this rule will allow the
States and EPA to determine appropriate requirements for specific PWSs
and to evaluate compliance with the rule. For the first 3 years after
LT2ESWTR promulgation, the major information requirements concern
monitoring activities and compliance tracking. The information
collection requirements are mandatory (40 CFR part 141) and the
information collected is not confidential.
    The estimate of annual average burden hours for the LT2ESWTR during
the first three years following promulgation is 141,295 hours. The
annual average cost estimate is $4.4 million for labor and $7 million
per year for operation and maintenance including lab costs (which is a
purchase of service). The burden hours per response is 0.63 hours and
the cost per response is $50.35. The frequency of response (average
responses per respondent) is 90.3, annually. The estimated number of
likely respondents is 2,503 (the product of burden hours per response,
frequency, and respondents does not total the annual average burden
hours due to rounding). Note that the burden hour estimates for the
first 3-year cycle include some large PWS but not small PWS monitoring.
Conversely, burden estimate for the second 3-year cycle will include
remaining monitoring for large systems (those serving between 10,000
and 49,999 people) and small PWS monitoring, but not for large PWS
serving 50,000 or more, which will have been completed by then.
    Burden means the total time, effort, or financial resources