[Federal Register Volume 78, Number 30 (Wednesday, February 13, 2013)]
[Rules and Regulations]
[Pages 10269-10365]
[FR Doc No: 2012-31205]

Vol. 78

Wednesday,

No. 30

February 13, 2013

Part II

Environmental Protection Agency

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40 CFR Parts 141 and 142

 National Primary Drinking Water Regulations: Revisions to the Total
Coliform Rule; Final Rule

Federal Register / Vol. 78 , No. 30 / Wednesday, February 13, 2013 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 141 and 142

[EPA-HQ-OW-2008-0878; FRL-9684-8]
RIN 2040-AD94

National Primary Drinking Water Regulations: Revisions to the
Total Coliform Rule

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is
finalizing revisions to the 1989 Total Coliform Rule (TCR). The Revised
Total Coliform Rule (RTCR) offers a meaningful opportunity for greater
public health protection beyond the 1989 TCR. Under the RTCR there is
no longer a monthly maximum contaminant level (MCL) violation for
multiple total coliform detections. Instead, the revisions require
systems that have an indication of coliform contamination in the
distribution system to assess the problem and take corrective action
that may reduce cases of illnesses and deaths due to potential fecal
contamination and waterborne pathogen exposure. This final rule also
updates provisions in other rules that reference analytical methods and
other requirements in the 1989 TCR (e.g., Public Notification and
Ground Water Rules). These revisions are in accordance with the 1996
Safe Drinking Water Act (SDWA) Amendments, which require EPA to review
and revise, as appropriate, each national primary drinking water
regulation no less often than every six years. These revisions also
conform with the SDWA provision that requires any revision to
``maintain, or provide for greater, protection of the health of
persons.'' As with the 1989 TCR, the RTCR applies to all public water
systems.

DATES: This final rule is effective on April 15, 2013. For judicial
purposes, this final rule is promulgated as of February 13, 2013. The
compliance date for the rule requirements is April 1, 2016. The
incorporation by reference of certain publications listed in the rule
is approved by the Director of the Federal Register (FR) as of April
15, 2013.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OW-2008-0878. All documents in the docket are listed on the
http://www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., Confidential Business
Information or other information whose disclosure is restricted by
statute. Certain other material, such as copyrighted material, is not
placed on the Internet and will be publicly available only in hard copy
form. Publicly available docket materials are available either
electronically through http://www.regulations.gov or in hard copy at
the Water Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave.
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to
4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is<PHONE_NUMBER>, and the
telephone number for the Water Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Sean Conley, Standards and Risk
Management Division, Office of Ground Water and Drinking Water (MC-
4607M), Environmental Protection Agency, 1200 Pennsylvania Ave. NW.,
Washington, DC 20460; telephone number:<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>For general information, contact the Safe Drinking
Water Hotline, telephone number:<PHONE_NUMBER>. The Safe Drinking
Water Hotline is open Monday through Friday, excluding legal holidays,
from 10 a.m. to 4 p.m. Eastern time.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Regulated Categories and Entities

    Entities potentially regulated by the RTCR are all public water
systems (PWSs). Regulated categories and entities include the
following:

------------------------------------------------------------------------
                Category                  Examples of regulated entities
------------------------------------------------------------------------
Industry...............................  Privately-owned community water
                                          systems (CWSs), transient non-
                                          community water systems
                                          (TNCWSs), and non-transient
                                          non-community water systems
                                          (NTNCWSs).
Federal, State, Tribal, and local        Publicly-owned CWSs, TNCWSs,
 governments.                             and NTNCWSs.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities regulated by this action. This
table lists the types of entities that EPA is now aware could
potentially be regulated by this action. Other types of entities not
listed in the table could also be regulated. To determine whether your
facility is regulated by this action, you should carefully examine the
definition of ``public water system'' in Sec.  141.2 and the section
entitled ``Coverage'' in Sec.  141.3 in title 40 of the Code of Federal
Regulations (CFR), and the applicability criteria in Sec.  141.851(b)
of this rule. If you have questions regarding the applicability of this
action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.

B. Copies of This Document and Other Related Information

    This document is available for download at [INSERT WEBSITE
ADDRESS]. For other related information, see preceding discussion on
docket. EPA also prepared a Response to Comments Document that
addresses the comments received during the comment period (to access
this document, search for Docket ID No. EPA-HQ-OW-2008-0878 in
www.regulations.gov).

C. Executive Summary

    EPA is finalizing the Revised Total Coliform Rule (RTCR). The RTCR
maintains the purpose of the 1989 Total Coliform Rule (TCR) to protect
public health by ensuring the integrity of the drinking water
distribution system and monitoring for the presence of microbial
contamination. EPA anticipates greater public health protection under
the RTCR, as it requires public water systems (PWSs) that are
vulnerable to microbial contamination to identify and fix problems, and
it establishes criteria for systems to qualify for and stay on reduced
monitoring, thereby providing incentives for improved water system
operation.
    The RTCR, as with the 1989 TCR, is the only microbial drinking
water regulation that applies to all PWSs. Systems are required to meet
a legal limit (i.e., maximum contaminant level (MCL)) for E. coli, as
demonstrated by required monitoring. The RTCR specifies the frequency
and timing of the microbial testing by water systems based on
population served, system type, and source water type. The rule also
requires public notification when

there is a potential health threat as indicated by monitoring results,
and when the system fails to identify and fix problems as required.
    The entities potentially affected by the RTCR are PWSs that are
classified as community water systems (CWSs) (e.g., systems that
provide water to year-round residents in places like homes or apartment
buildings) or non-community water systems (NCWSs) (e.g., systems that
provide water to people in locations such as schools, office buildings,
restaurants, etc.); State primacy agencies; and local and tribal
governments. The RTCR applies to approximately 155,000 PWSs that serve
approximately 310 million (M) individuals.
    The RTCR establishes a health goal (maximum contaminant level goal,
or MCLG) and an MCL for E. coli, a more specific indicator of fecal
contamination and potential harmful pathogens than total coliforms. EPA
replaces the MCLG and MCL for total coliforms with a treatment
technique for coliforms that requires assessment and corrective action.
Many of the organisms detected by total coliform methods are not of
fecal origin and do not have any direct public health implication.
    Under the treatment technique for coliforms, total coliforms serve
as an indicator of a potential pathway of contamination into the
distribution system. A PWS that exceeds a specified frequency of total
coliform occurrence must conduct an assessment to determine if any
sanitary defects exist (a sanitary defect is defined by the RTCR as a
``defect that could provide a pathway of entry for microbial
contamination into the distribution system or that is indicative of a
failure or imminent failure of a barrier that is already in place'');
if any are found, the system must correct them. In addition, under the
treatment technique requirements, a PWS that incurs an E. coli MCL
violation must conduct an assessment and correct any sanitary defects
found.
    The RTCR links monitoring frequency to compliance monitoring
results and system performance. It provides criteria that well-operated
small systems must meet to qualify for and stay on reduced monitoring.
It requires increased monitoring for high-risk small systems with
unacceptable compliance history. It also requires some new monitoring
requirements for seasonal systems (such as state and national parks).
    The RTCR eliminates public notification requirements based only on
the presence of total coliforms. Total coliforms in the distribution
system may indicate a potential pathway for contamination but by
themselves do not indicate a health threat. Instead, the RTCR requires
public notification when an E. coli MCL violation occurs, indicating a
potential health threat, or when a PWS fails to conduct the required
assessment and corrective action.
    EPA believes that the provisions of the RTCR will improve public
health protection by requiring assessment and corrective action and
providing incentives for improved operation. The estimated net
incremental cost of the RTCR is $14 million annually at either a three
or seven percent discount rate. This represents total increased costs
relative to 1989 TCR provisions. PWSs are estimated to incur
approximately 97 percent of the rule's net annualized present value
costs at the three percent discount rate. States and other primacy
agencies incur the remaining costs.

Abbreviations Used in This Document

AGI--Acute Gastrointestinal Illness
AIDS--Acquired Immune Deficiency Syndrome
AIP--Agreement in Principle
AWWA--American Water Works Association
ATP--Alternate Test Procedure
BAT--Best Available Technology
C--Celsius
CCR--Consumer Confidence Report
CDC--Centers for Disease Control and Prevention
CFR--Code of Federal Regulations
COI--Cost of Illness
CWS--Community Water System
DBP--Disinfection Byproduct
DWC--Drinking Water Committee
EA--Economic Analysis
EC-MUG--EC Medium with MUG
EPA--United States Environmental Protection Agency
ERS--Economic Research Service
ETV--Environmental Technology Verification
FR--Federal Register
GWR--Ground Water Rule
GWUDI--Ground Water Under the Direct Influence of Surface Water
HRRCA--Health Risk Reduction and Cost Analysis
HUS--Hemolytic Uremic Syndrome
ICR--Information Collection Request
IESWTR--Interim Enhanced Surface Water Treatment Rule
M--Million
MCL--Maximum Contaminant Level
MCLG--Maximum Contaminant Level Goal
mg/L--Milligrams per Liter
ml--Milliliters
MRDL--Maximum Residual Disinfectant Level
MUG--4-methylumbelliferyl-Beta-D-glucuronide
NCWS--Non-community Water System
NDWAC--National Drinking Water Advisory Council
NPDWR--National Primary Drinking Water Regulation
NTNCWS--Non-Transient Non-Community Water System
NTU--Nephelometric Turbidity Unit
OMB--Office of Management and Budget
O&M--Operation and Maintenance
PN--Public Notification
PWS--Public Water System
RFA--Regulatory Flexibility Act
RTCR--Revised Total Coliform Rule
SAB--Science Advisory Board
SBA--Small Business Administration
SDWA--Safe Drinking Water Act
SDWIS--Safe Drinking Water Information System
SDWIS/FED--Safe Drinking Water Information System Federal Version
SOP--Standard Operating Procedure
Stage 1 DBPR--Stage 1 Disinfectants and Disinfection Byproducts Rule
Stage 2 DBPR--Stage 2 Disinfectants and Disinfection Byproducts Rule
SWTR--Surface Water Treatment Rule
TCR--Total Coliform Rule
TCRDSAC--Total Coliform Rule/Distribution System Advisory Committee
TMF--Technical, Managerial, and Financial
TNCWS--Transient Non-Community Water System
TWG--Technical Work Group
T&C--Technology and Cost
US--United States
UV--Ultraviolet

Table of Contents

I. General Information
    A. Regulated Categories and Entities
    B. Copies of This Document and Other Related Information
    C. Executive Summary
II. Background
    A. Statutory Authority
    B. Purpose of the Rule
    C. Rule Development
    1. Total Coliform Rule Distribution System Advisory Committee
(TCRDSAC)
    2. Stakeholder Involvement
    D. Public Health Concerns Addressed by the Revised Total
Coliform Rule
    1. Public Health Concerns, Fecal Contamination, and Waterborne
Pathogens
    2. Indicators
    3. Occurrence of Fecal Contamination and Waterborne Pathogens
III. Requirements of the Revised Total Coliform Rule
    A. RTCR Definitions
    1. Assessment
    2. Clean Compliance History
    3. Sanitary Defect
    4. Seasonal Systems
    B. Rule Construct: MCLG and MCL for E. coli and Coliform
Treatment Technique
    1. MCLG and MCL
    2. Coliform Treatment Technique
    C. Monitoring
    1. Requirements
    2. Key Issues Raised
    D. Repeat samples
    1. Requirements
    2. Key Issues Raised
    E. Coliform Treatment Technique
    1. Coliform Treatment Technique Triggers
    2. Assessment
    3. Corrective Action
    F. Violations
    1. Requirements
    2. Key Issues Raised

    G. Providing Notification and Information to the Public
    1. Requirements
    2. Key Issues Raised
    H. Reporting and Recordkeeping
    1. Requirements
    2. Key Issues Raised
    I. Analytical Methods
    1. AIP-Related Method Issues
    2. Other Method Issues
    J. Systems Under EPA Direct Implementation
    K. Compliance Date
IV. Other Elements of the Revised Total Coliform Rule
    A. Best Available Technology
    1. Requirements
    2. Key Issues Raised
    B. Variances and Exemptions
    1. Requirements
    2. Key Issues Raised
    C. Revisions to Other NPDWRs as a Result of the RTCR
    D. Storage Facility Inspection
V. State Implementation
    A. Primacy
    1. Requirements
    2. Key Issues Raised
    B. State Recordkeeping and Reporting and SDWIS
    1. Recordkeeping
    2. Reporting
    3. SDWIS
    4. Key Issues Raised
VI. Economic Analysis (Health Risk Reduction and Cost Analysis)
    A. Regulatory Options Considered
    B. Major Sources of Data and Information Used in Supporting
Analyses
    1. Safe Drinking Water Information System Federal version data
    2. Six-Year Review 2 data
    3. Other information sources
    C. Occurrence and Predictive Modeling
    1. Model Used for PWSs Serving <= 4,100 People
    2. Model Used for PWSs Serving > 4,100 People
    D. Baseline Profiles
    E. Anticipated Benefits of the RTCR
    1. Relative Risk Analysis
    2. Changes in Violation Rates and Corrective Actions
    3. Nonquantifiable Benefits
    F. Anticipated Costs of the RTCR
    1. Total Annualized Present Value Costs
    2. PWS Costs
    3. State Costs
    4. Nonquantifiable Costs
    G. Potential Impact of the RTCR on Households
    H. Incremental Costs and Benefits
    I. Benefits From Simultaneous Reduction of Co-occurring
Contaminants
    J. Change in Risk From Other Contaminants
    K. Effects of Fecal Contamination and/or Waterborne Pathogens on
the General Population and Sensitive Subpopulations
    1. Risk to Children, Pregnant Women, and the Elderly
    2. Risk to Immunocompromised Persons
    L. Uncertainties in the Benefit and Cost Estimates for the RTCR
    1. Inputs and Their Uncertainties
    2. Sensitivity Analysis
    M. Benefit Cost Determination for the RTCR
    N. Comments Received in Response to EPA's Requests for Comment
    1. SAB's Concerns
    2. Costs of Major Distribution System Appurtenances
    3. Annual Monitoring and Annual Site Visits
    4. Effectiveness of Assessments
    O. Other Comments Received by EPA
    1. Quantifying Health Benefits
    2. Return to Reduced Monitoring
    3. Shift of State Resources
    4. State burden
VII. Statutory and Executive Order Review
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Consultations With the Science Advisory Board, National
Drinking Water Advisory Council, and the Secretary of Health and
Human Services
    L. Considerations of Impacts on Sensitive Subpopulations as
Required by Section 1412(b)(3)(C)(i)(V) of the 1996 Amendments of
the Safe Drinking Water Act (SDWA)
    M. Effect of Compliance with the RTCR on the Technical,
Financial, and Managerial Capacity of Public Water Systems
    N. Congressional Review Act
VIII. References

II. Background

A. Statutory Authority

    The Safe Drinking Water Act (SDWA) requires the EPA to review and
revise, as appropriate, each existing national primary drinking water
regulation (NPDWR) no less often than every six years (SDWA section
1412(b)(9), 42 U.S.C. 300g-1(b)(9)). In 2003, EPA completed its review
of the 1989 TCR (USEPA 1989a, 54 FR 27544, June 29, 1989) and 68 NPDWRs
for chemicals that were promulgated prior to 1997 (USEPA 2003, 68 FR
42908, July 18, 2003). The purpose of the review was to identify new
health risk assessments, changes in technology, and other factors that
would provide a health-related or technological basis to support a
regulatory revision that would maintain or improve public health
protection. In the Six-Year Review 1 determination published in July
2003 (USEPA 2003, 68 FR 42908, July 18, 2003), EPA stated its intent to
revise the 1989 TCR.

B. Purpose of the Rule

    EPA promulgated the 1989 TCR to decrease the risk of waterborne
illness. Among all SDWA rules promulgated for preventing waterborne
illness, only the TCR applies to all PWSs, making the rule an essential
component of the multi-barrier approach in public health protection
against endemic and epidemic disease. In combination with the other
SDWA rules (e.g., the Ground Water Rule (GWR) (USEPA 2006c, 71 FR
65574, November 8, 2006) and the suite of surface water treatment rules
(USEPA 1989b; USEPA 1998b; USEPA 2002; USEPA 2006d)), the RTCR will
better address the 1989 TCR objectives and enhance the multi-barrier
approach to protecting public health, especially with respect to small
ground water PWSs.
    In recent years, the number of violations under the 1989 TCR have
remained relatively steady, as shown and discussed in Exhibit 4.11 and
Appendix G of the Economic Analysis for the Final Revised Total
Coliform Rule (RTCR EA) (USEPA 2012a). EPA believes that this is
reflective of a steady state among PWSs complying with the 1989 TCR and
any improvements likely to occur under that rule have largely been
achieved. In outlining recommendations for further reductions in
occurrence, EPA and the Total Coliform Rule Distribution System
Advisory Committee (TCRDSAC) developed an Agreement in Principle (AIP)
(USEPA 2008c), which became the basis of the proposed and final RTCR.
See section II.C.1 of this preamble, Total Coliform Distribution System
Advisory Committee (TCRDSAC), for more information about the TCRDSAC
and the AIP.
    The RTCR aims for greater public health protection than the 1989
TCR in a cost-effective manner by: (1) Maintaining the objectives of
the 1989 TCR (i.e., to evaluate the effectiveness of treatment, to
determine the integrity of the distribution system, and to signal the
possible presence of fecal contamination); (2) reducing the potential
pathways of contamination into the distribution system (see section
II.D of this preamble, Public Health Concerns Addressed by the Revised
Total Coliform Rule); (3) using the optimal indicator for the intended
objectives (i.e., using total coliforms as an indicator of system
operation and

condition rather than an immediate public health concern and using E.
coli as a fecal indicator (see sections II.D, Public Health Concerns
Addressed by the Revised Total Coliform Rule, and III.B, Rule
Construct: MCLG and MCL for E. coli and Coliform Treatment Technique,
of this preamble)); (4) requiring more stringent standards than those
of the 1989 TCR for systems to qualify for reduced monitoring (see
sections III.C.1.b.iii, Reduced monitoring, and III.C.1.c.iii, Reduced
monitoring, of this preamble); and (5) requiring systems that may be
vulnerable to contamination, as indicated by their monitoring results
and by the nature of their operation (e.g., seasonal systems), to
monitor more frequently and have in place procedures that will minimize
the incidence of contamination (e.g., requiring start-up procedures for
seasonal systems) (see sections III.C.1.b.iv, Increased monitoring,
III.C.1.c.iv, Requirements for returning to monthly monitoring, and
III.C.1.f, Seasonal systems, of this preamble). EPA, therefore,
anticipates greater public health protection under the RTCR compared to
the 1989 TCR because of the RTCR's more preventive approach to
identifying and fixing problems that affect or may affect public
health.

C. Rule Development

1. Total Coliform Rule Distribution System Advisory Committee (TCRDSAC)
    The revisions to the 1989 TCR are primarily based on the
recommendations of the Total Coliform Rule Distribution System Advisory
Committee (``TCRDSAC'' or the ``advisory committee''). EPA established
the TCRDSAC in June 2007 in accordance with the provisions of the
Federal Advisory Committee Act, 5 U.S.C. App.2, 9(c), to provide
recommendations to EPA on revisions to the 1989 TCR and on what
information about distribution system issues is needed to better
understand and address possible public health impacts from potential
degradation of drinking water quality in distribution systems (USEPA
2007a, 72 FR 35869, June 29, 2007).
    All advisory committee members agreed to a set of recommendations
and signed a final Agreement in Principle (AIP) in September 2008.
Pursuant to the AIP, EPA on July 14, 2010 proposed revisions to the
1989 TCR (USEPA 2010a, 75 FR 40926, July 14, 2010) that, to the maximum
extent consistent with EPA's legal obligations, had the same substance
and effect as the elements of the AIP. The AIP and details about the
advisory committee can be found at EPA's Web site at http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/regulation_revisions_tcrdsac.cfm.
2. Stakeholder Involvement
    In accordance with one of the recommendations of the TCRDSAC, EPA
held two annual stakeholder meetings, prior to publishing the proposed
revisions, to which all advisory committee members and the public at
large were invited. In April 2009 and May 2010, EPA held these
stakeholder meetings to provide updates and an opportunity for
stakeholders to provide feedback on the development of a proposed RTCR
that had the same substance and effect as the recommendations in the
AIP.
    EPA proposed the RTCR on July 14, 2010 (USEPA 2010a, 75 FR 40926,
July 14, 2010) and requested public comment. EPA received approximately
150 comment letters on the proposal and considered the comments in
making revisions to the final RTCR. Key issues raised by the commenters
are discussed in their corresponding sections of this preamble. A
Response to Comments Document is available in the docket of the RTCR
(search for Docket ID No. EPA-HQ-OW-2008-0878 in www.regulations.gov).
    During the public comment period for the proposed RTCR, EPA also
held several meetings to solicit and provide the public with
information about the provisions of the proposed rule. In addition to
consulting with the advisory committee and holding stakeholder
meetings, EPA consulted with specific stakeholders such as the National
Drinking Water Advisory Council (NDWAC), the Science Advisory Board
(SAB), and Tribal representatives, among others. These consultations
are discussed in section VII of this preamble, Statutory and Executive
Order Review.

D. Public Health Concerns Addressed by the Revised Total Coliform Rule

1. Public Health Concerns, Fecal Contamination, and Waterborne
Pathogens
    The RTCR aims to increase public health protection through the
reduction of potential pathways of entry for fecal contamination into
the distribution system. Since these potential pathways represent
vulnerabilities in the distribution system whereby fecal contamination
and/or waterborne pathogens, including bacteria, viruses and parasitic
protozoa could possibly enter the system, the reduction of these
pathways in general should lead to reduced exposure and associated risk
from these contaminants. Fecal contamination and waterborne pathogens
can cause a variety of illnesses, including acute gastrointestinal
illness (AGI) with diarrhea, abdominal discomfort, nausea, vomiting,
and other symptoms. Most AGI cases are of short duration and result in
mild illness. Other more severe illnesses caused by waterborne
pathogens include hemolytic uremic syndrome (HUS) (kidney failure),
hepatitis, and bloody diarrhea (WHO 2004). Chronic disease such as
irritable bowel syndrome, renal impairment, hypertension,
cardiovascular disease and reactive arthritis can result from infection
by a waterborne agent (Clark et al. 2008; Clark et al. 2010; Moorin et
al. 2010).
    When humans are exposed to and infected by waterborne enteric
pathogens, the pathogens become capable of reproducing in the
gastrointestinal tract. As a result, healthy humans shed pathogens in
their feces for a period ranging from days to weeks. This shedding of
pathogens often occurs in the absence of any signs of clinical illness.
Regardless of whether a pathogen causes clinical illness in the person
who sheds it in his or her feces, the pathogen being shed may infect
other people directly by person-to-person spread, contact with
contaminated surfaces, and other means referred to as secondary spread.
As a result, waterborne pathogens that are initially waterborne may
subsequently infect other people through a variety of routes (WHO
2004). Sensitive subpopulations are at greater risk from waterborne
disease than the general population (Gerba et al. 1996). For a
discussion of sensitive subpopulations, see section VII.L of this
preamble, Impacts on Sensitive Subpopulations as Required by Section
1412(b)(3)(c)(i)(V) of the 1996 Amendments of the Safe Drinking Water
Act (SDWA).
2. Indicators
    Total coliforms are a group of closely related bacteria that, with
a few exceptions, are not harmful to humans. Coliforms are abundant in
the feces of warm-blooded animals, but can also be found in aquatic
environments, in soil, and on vegetation. Coliform bacteria may be
transported to surface water by run-off or to ground water by
infiltration. Total coliforms are common in ambient water and may be
injured by environmental stresses such as lack of nutrients, and water
treatments such as chlorine disinfection, in a manner similar to most
bacterial pathogens and

many viral enteric pathogens (including fecal pathogens). EPA considers
total coliforms to be a useful indicator that a potential pathway
exists through which fecal contamination can enter the distribution
system. This is because the absence (versus the presence) of total
coliforms in the distribution system indicates a reduced likelihood
that fecal contamination and/or waterborne pathogens are occurring in
the distribution system.
    Under the 1989 TCR, each total coliform-positive sample is assayed
for either fecal coliforms or E. coli. Fecal coliform bacteria are a
subgroup of total coliforms that traditionally have been associated
with fecal contamination. Since the promulgation of the 1989 TCR, more
information and understanding of the suitability of fecal coliform and
E. coli as indicators have become available. Study has shown that the
fecal coliform assay is imprecise and too often captures bacteria that
do not originate in the human or mammal gut (Edberg et al. 2000). On
the other hand, E. coli is a more restricted group of coliform bacteria
that almost always originate in the human or animal gut (Edberg et al.
2000). Thus, E. coli is a better indicator of fecal contamination than
fecal coliforms. The provisions of the RTCR reflect the improved
understanding of the value of total coliforms and E. coli as
indicators.
3. Occurrence of Fecal Contamination and Waterborne Pathogens
    a. Presence of fecal contamination. Fecal contamination is a very
general term that includes all of the organisms found in feces, both
pathogenic and nonpathogenic. Fecal contamination can occur in drinking
water both through use and inadequate treatment of contaminated source
water as well as direct intrusion of fecal contamination into the
drinking water distribution system. Lieberman et al. (1994) discuss the
general association between fecal contamination and waterborne
pathogens. Biofilms in distribution systems may harbor waterborne
bacterial pathogens and accumulate enteric viruses and parasitic
protozoa (Skraber et al. 2005; Helmi et al. 2008). Waterborne pathogens
in biofilms may have entered the distribution system as fecal
contamination from humans or animals.
    Co-occurrence of indicators and waterborne pathogens is difficult
to measure. While the analytical methods approved by EPA to assay for
E. coli are able to detect indicators of fecal contamination, they do
not specifically identify most of the pathogenic E. coli strains. There
are at least 700 recognized E. coli strains (Kaper et al. 2004) and
about 10 percent of recognized E. coli strains are pathogenic to humans
(Feng 1995; Hussein 2007; Kaper et al. 2004). Pathogenic E. coli
include E. coli O157:H7, which is the primary cause of HUS in the
United States (Rangel et al. 2005). The US Centers for Disease Control
and Prevention (CDC) estimates that there are 73,000 cases of illness
each year in the US due to E. coli O157:H7 (Mead et al. 1999). The CDC
estimates that about 15 percent of all reported E. coli O157:H7 cases
are due to water contamination (Rangel et al. 2005). Active
surveillance by CDC shows that 6.3 percent of E. coli O157:H7 cases
progress to HUS (Griffin and Tauxe 1991; Gould et al. 2009) and about
12 percent of HUS cases result in death within four years (Garg et al.
2003). About 4 to 15 percent of cases are transmitted within households
by secondary transmission (Parry and Salmon 1998).
    Because EPA-approved standard methods for E. coli do not typically
identify the presence of the pathogenic E. coli strains, an E. coli-
positive monitoring result is an indicator of fecal contamination but
is not necessarily a measure of waterborne pathogen occurrence.
Specialized assays and methods are used to identify waterborne
pathogens, including pathogenic E. coli.
    One notable exception is the data reported by Cooley et al. (2007),
which showed high concentrations of pathogenic E. coli strains in
samples containing high concentrations of fecal indicator E. coli.
These data are from streams and other poor quality surface waters
surrounding California spinach fields associated with the 2006 E. coli
O157:H7 foodborne outbreak. Data equivalent to these samples are not
available from drinking water samples collected under the 1989 TCR.
    Because E. coli is an indicator of fecal contamination (Edberg et
al. 2000), and because of the general association between fecal
contamination and waterborne pathogens (Lieberman et al. 1994;
Lieberman et al. 2002), E. coli is a meaningful indicator for fecal
contamination and the potential presence of associated pathogen
occurrence.
    b. Waterborne disease outbreaks. The CDC defines a waterborne
disease outbreak as occurring when at least two persons experience a
similar illness after ingesting a specific drinking water (or after
exposure to recreational water) contaminated with pathogens (or
chemicals) (Kramer et al. 1996), or when one person experiences amoebic
meningoencephalitis after similar waterborne exposure. The CDC
maintains a database on waterborne disease outbreaks in the United
States. The database is based upon responses to a voluntary and
confidential survey form that is completed by State and local public
health officials.
    The National Research Council strongly suggests that the number of
identified and reported outbreaks in the CDC database for surface and
ground waters represents only a small percentage of the actual number
of waterborne disease outbreaks (NRC 1997; Bennett et al. 1987; Hopkins
et al. 1985 for Colorado data). Under-reporting occurs because most
waterborne outbreaks in community water systems are not recognized
until a sizable proportion of the population is ill (Perz et al. 1998;
Craun 1996), perhaps 1 percent to 2 percent of the population (Craun
1996). EPA drinking water regulations are designed to protect against
endemic waterborne disease and to minimize waterborne outbreaks. In
contrast to outbreaks, endemic disease refers to the persistent low to
moderate level or the usual ongoing occurrence of illness in a given
population or geographic area (Craun et al. 2006).

III. Requirements of the Revised Total Coliform Rule

    The RTCR maintains and strengthens the objectives of the 1989 TCR
and is consistent with the recommendations in the AIP. The objectives
are: (1) To evaluate the effectiveness of treatment, (2) to determine
the integrity of the distribution system, and (3) to signal the
possible presence of fecal contamination. The RTCR better addresses
these objectives by requiring systems that may be vulnerable to fecal
contamination (as indicated by their monitoring results) to do an
assessment, to identify whether any sanitary defect(s) is (are)
present, and to correct the defects. Therefore, the Agency anticipates
greater public health protection under the RTCR compared to the 1989
TCR because of its more preventive approach to identifying and fixing
problems that affect or may affect public health. The following is an
overview of the key provisions of the RTCR:
     MCLG and MCL for E. coli and coliform treatment technique
for protection against potential fecal contamination. The RTCR
establishes a maximum contaminant level goal (MCLG) and maximum
contaminant level (MCL) for E. coli. Under the RTCR there is no longer
a monthly maximum contaminant level (MCL) violation for multiple total
coliform detections. The RTCR takes a preventive approach to protecting
public health by establishing

a coliform treatment technique for protection against potential fecal
contamination. The treatment technique uses both total coliforms and E.
coli monitoring results to start an evaluation process that, where
necessary, requires the PWS to conduct follow-up corrective action that
could prevent future incidences of contamination and exposure to fecal
contamination and/or waterborne pathogens. See section III.B of this
preamble, Rule Construct: MCLG and MCL for E. coli and Coliform
Treatment Technique, for further discussion on the MCLG, MCL, and
treatment technique requirements.
     Monitoring. As with the 1989 TCR, PWSs will continue to
monitor for total coliforms and E. coli according to a sample siting
plan and schedule specific to the system.
    Sample siting plans under the RTCR must continue to be
representative of the water throughout the distribution system. Under
the RTCR, systems have the flexibility to propose repeat sample
locations that best verify and determine the extent of potential
contamination of the distribution system rather than having to sample
within five connections upstream and downstream of the total coliform-
positive sample location. In lieu of proposing new repeat sample
locations, the systems may stay with the default used under the 1989
TCR of within-five-connections-upstream-and-downstream of the total
coliform-positive sample location.
    As with the 1989 TCR, the RTCR allows reduced monitoring for some
small ground water systems. The RTCR is expected to improve public
health protection compared to the 1989 TCR by requiring small ground
water systems that are on or wish to conduct reduced monitoring to meet
certain eligibility criteria. Examples of the criteria include a
sanitary survey showing that the system is free of sanitary defects, a
clean compliance history for 12 months, and a recurring annual site
visit by the State and/or a voluntary Level 2 assessment for systems on
annual monitoring.
    For small ground water systems, the RTCR requires increased
monitoring for high-risk systems such as those that do not have a clean
compliance history under the RTCR. The RTCR specifies conditions under
which systems will no longer be eligible for reduced monitoring and be
required to return to routine monitoring or to monitor at an increased
frequency.
    The RTCR requires systems on a quarterly or annual monitoring
frequency (applicable only to ground water systems serving 1,000 or
fewer people) to collect at least three additional routine monitoring
samples the month following one or more total coliform-positive
samples, unless the State waives the additional routine monitoring.
This is a reduction in the required number of additional routine
samples from the 1989 TCR, which requires at least five routine samples
in the month following a total coliform-positive sample for all systems
serving 4,100 or fewer people.
    The 1989 TCR requires all systems serving 1,000 or fewer people to
collect at least four repeat samples while requiring PWSs serving 1,000
people or greater to collect three repeat samples. The RTCR requires
three repeat samples after a routine total coliform-positive sample,
regardless of the system type and size.
    See sections III.C, Monitoring, and III.D, Repeat Samples, of this
preamble for detailed discussions of the routine monitoring and repeat
sampling requirements of the RTCR.
     Seasonal systems. For the first time, the RTCR establishes
monitoring requirements specific to seasonal systems. Seasonal systems
represent a special case in that the shutdown and start-up of these
water systems present additional opportunities for contamination to
enter or spread through the distribution system. Under the RTCR,
seasonal systems must demonstrate completion of a State-approved start-
up procedure. See sections III.A.4, Seasonal systems, and III.C.1.f,
Seasonal systems, of this preamble for further discussion of
requirements for seasonal systems.
     Assessment and corrective action. As part of a treatment
technique, all PWSs are required to assess their systems when
monitoring results show that the system may be vulnerable to
contamination. Systems must conduct either a Level 1 assessment or a
more detailed Level 2 assessment depending on the level of concern
raised by the results of indicator sampling. The system is responsible
for correcting any sanitary defect(s) found through either a Level 1 or
Level 2 assessment. See section III.E of this preamble, Coliform
Treatment Technique, for more discussion of the treatment technique
requirement of the RTCR.
     Violations and public notification. The RTCR establishes
an E. coli MCL violation, a treatment technique violation, a monitoring
violation, and a reporting violation. Public notification is required
for each type of violation, with the type of notification dependent on
the degree of potential public health concern. This is consistent with
EPA's current public notification requirements under 40 CFR part 141
subpart Q. The RTCR also modifies the public notification and Consumer
Confidence Report language to reflect the construct of the rule. See
sections III.F, Violations, and III.G, Providing Notification and
Information to the Public, of this preamble for further discussions of
violations and public notification under the RTCR.
     Transition to the RTCR. The RTCR allows all systems to
transition to the new rule at their 1989 TCR monitoring frequency,
including systems on reduced monitoring under the 1989 TCR. For ground
water systems serving 1,000 or fewer people, States must conduct a
special monitoring evaluation during each sanitary survey after the
compliance effective date of the RTCR. Initial grandfathering of
monitoring frequencies reduces State burden by not requiring the State
to determine appropriate monitoring frequency at the same time the
State is working to adopt primacy, develop policies, and train their
own staff and the PWSs in the State.
    The provisions of the RTCR are contained in the new 40 CFR part 141
subpart Y, superseding 40 CFR 141.21 beginning April 1, 2016.

A. RTCR Definitions

1. Assessment
    a. Provisions. EPA is defining a Level 1 assessment and a Level 2
assessment to help in the implementation of the RTCR and to better
differentiate between the two levels of assessments.
    A Level 1 assessment is an evaluation to identify the possible
presence of sanitary defects, defects in distribution system coliform
monitoring practices, and (when possible) the likely reason that the
system triggered the assessment. It is conducted by the system operator
or owner (or his designated representative). Minimum elements include
review and identification of atypical events that could affect
distributed water quality or indicate that distributed water quality
was impaired; changes in distribution system maintenance and operation
that could affect distributed water quality (including water storage);
source and treatment considerations that bear on distributed water
quality, where appropriate (e.g., whether a ground water system is
disinfected); existing water quality monitoring data; and inadequacies
in sample sites, sampling protocol, and sample processing. The system
must conduct the assessment consistent with any State directives that
tailor specific assessment elements with respect to the size and type
of the system and the size, type, and

characteristics of the distribution system.
    A Level 2 assessment is an evaluation to identify the possible
presence of sanitary defects, defects in distribution system coliform
monitoring practices, and (when possible) the likely reason that the
system triggered the assessment. A Level 2 assessment provides a more
detailed examination of the system (including the system's monitoring
and operational practices) than does a Level 1 assessment through the
use of more comprehensive investigation and review of available
information, additional internal and external resources, and other
relevant practices. It is conducted by an individual approved by the
State, which may include the system operator. Minimum elements include
review and identification of atypical events that could affect
distributed water quality or indicate that distributed water quality
was impaired; changes in distribution system maintenance and operation
that could affect distributed water quality (including water storage);
source and treatment considerations that bear on distributed water
quality, where appropriate (e.g., whether a ground water system is
disinfected); existing water quality monitoring data; and inadequacies
in sample sites, sampling protocol, and sample processing. The system
must conduct the assessment consistent with any State directives that
tailor specific assessment elements with respect to the size and type
of the system and the size, type, and characteristics of the
distribution system. The system must comply with any expedited actions
or additional actions required by the State in the case of an E. coli
MCL violation.
    b. Key issues raised. EPA did not propose definitions for Level 1
and Level 2 assessments. However, based on the comments EPA received,
there was concern that the distinction between the two levels of
assessment is not sufficiently laid out in the rule language. This
might pose some problems in the implementation of the RTCR. In
response, EPA is defining a Level 1 assessment and a Level 2
assessment. This issue and the RTCR requirements regarding assessments
are discussed further in section III.E.2 of this preamble, Assessment.
2. Clean Compliance History
    a. Provisions. In the final RTCR, EPA is defining ``clean
compliance history'' as a record of no maximum contaminant level (MCL)
violations under 40 CFR 141.63; no monitoring violations under 40 CFR
141.21 or subpart Y; and no coliform treatment technique trigger
exceedances or coliform treatment technique violations under subpart Y.
This is the same definition that the advisory committee recommended in
the AIP and that EPA proposed in July 2010 (USEPA 2010a, 75 FR 40926,
July 14, 2010). The term is specific to RTCR compliance and is used to
determine eligibility of systems for reduced monitoring. It does not
include violations under other existing NPDWRs. Systems must have a
``clean compliance history'' for a minimum of 12 months to qualify for
reduced monitoring (see sections III.C.1.b.iii, Reduced monitoring, and
III.C.1.c.iii, Reduced monitoring, of this preamble regarding reduced
monitoring).
    However, while the definition of ``clean compliance history''
includes only 1989 TCR/RTCR violations, the State may (and should)
consider compliance history under other rules if relevant. For example,
failure to take a triggered source water sample required under the GWR
(USEPA 2006, 71 FR 65574, November 8, 2006) may appropriately cause the
State to not allow less frequent monitoring because this could (1) lead
the system to miss source water contamination and (2) indicate a
system's lack of attention to regulatory requirements or proper
operation.
    b. Key issues raised. EPA received comments that a record of no
monitoring violations should not be included in the definition of
``clean compliance history.'' Commenters are concerned that small
systems, which experience frequent turnover or shortage of staff, may
not be able to qualify for reduced monitoring if they miss a sample or
two. EPA believes that a system on a reduced monitoring frequency
(i.e., less than monthly, either quarterly or annually) must be able to
demonstrate that it is capable of delivering safe water and maintaining
proper attention to the water system, even on an infrequent monitoring
schedule, by meeting certain criteria (see sections III.C.1.b.iii,
Reduced monitoring, and III.C.1.c.iii, Reduced monitoring, of this
preamble for discussion about the reduced monitoring criteria). Small
systems monitoring less frequently than monthly, especially those
monitoring only annually, already have a lower probability of detecting
a contamination event compared to systems that monitor monthly. Because
of the intermittent nature of contamination and the fact that these
systems are already on a significantly reduced monitoring frequency, it
is very important that these systems take their samples as required.
Because these systems monitor so infrequently, EPA recommends that the
States use the annual site visits as an opportunity to review system
operations, reinforce the importance of collecting the required
samples, and to identify and require correction of any sanitary
defects. The State can make sure that the system takes its required
sample, and therefore avoids incurring a monitoring violation because
of a missed sample (see section III.C.1.b.iii of this preamble, Reduced
monitoring, for discussion of annual monitoring). EPA is therefore
retaining the definition of ``clean compliance history'' as proposed
because EPA believes that removing the record of no monitoring
violation from the definition would be less protective of public
health. However, EPA is providing flexibility to the States in
considering monitoring violations in TNCWSs when determining whether
the system must go on increased monthly monitoring. See sections
III.C.1.b, Ground water NCWSs serving <= 1,000 people, and III.C.2.b,
Ground water NCWSs serving <= 1,000 people, of this preamble for a more
detailed discussion.
3. Sanitary Defect
    a. Provisions. EPA is finalizing the definition of sanitary defect
as proposed in July 2010 (USEPA 2010a, 75 FR 40926, July 14, 2010). It
is defined as a ``defect that could provide a pathway of entry for
microbial contamination into the distribution system or that is
indicative of a failure or imminent failure in a barrier that is
already in place.'' As stated in the proposed rule, the first part of
the definition focuses on the problems in the distribution system that
may provide a pathway for contaminants to enter the distribution system
and its implication for potential exposure to both microbial and
chemical contaminants. The second part of the definition also
recognizes the importance of having barriers in place to prevent the
entry of microbial contaminants into the distribution system.
Indications of failure or imminent failure of these barriers are
defects that require corrective action.
    The advisory committee deliberated on the definition of sanitary
defect and suggested that the definition should be broad enough to
facilitate corrective action without absolute confirmation of cause and
effect, as such confirmation may be impossible or may significantly
delay corrections that would address a sanitary defect that represents
a potential threat to public health. Conversely, the language is not
intended to suggest that corrections must be undertaken where the
linkage between the defect and public health is tenuous. The advisory
committee also agreed that

it is their intent that nothing in the definition of sanitary defects
precludes conducting an assessment of every element on the example
checklists for Level 1 and Level 2 assessments (USEPA 2008d).
    b. Key issues raised. EPA received comments regarding the
relationship between sanitary defects under the RTCR and ``significant
deficiencies' under other regulations and the possible confusion
between the two terms. One commenter said that the requirement to
identify and correct sanitary defects under the RTCR is very similar to
the GWR's requirement to identify and correct significant deficiencies,
and that EPA should therefore consider which rule is more effective at
minimizing risk of contamination.
    The advisory committee specifically stated that ``sanitary
defects'' are specific to the assessment and corrective action
requirements of the RTCR and are not intended to be linked directly to
``significant deficiencies'' under the Interim Enhanced Surface Water
Treatment Rule (IESWTR) (USEPA 1998, 63 FR 69389, December 16, 1998)
and the GWR, although some problems could meet either definition. The
term ``significant deficiency'' is tied or associated with the eight
elements of a sanitary survey. There are problems that are ``sanitary
defects'' and are also ``significant deficiencies''. For instance,
source water problems like those associated with the well casing may
fit the definition of both a ``sanitary defect'' and a ``significant
deficiency.'' Depending on when the problem was identified (i.e.,
during a sanitary survey or during an assessment triggered under RTCR)
and on the guidelines set by the State, the system should coordinate
with their State regarding how to characterize the problem and how to
coordinate the corrective action requirements under the GWR and RTCR,
if needed. Conversely, there are problems that are ``sanitary defects''
but are not ``significant deficiencies'' and vice versa. ``Significant
deficiency'' can include problems other than those in the distribution
system that can have an effect on the long term viability of the system
in delivering safe water to its customers. ``Significant deficiencies''
can also exist in the areas of reporting and data verification, system
management and operation, and operator compliance with State
requirements, which are not considered ``sanitary defects.''
    Furthermore, although there might be overlap between a ``sanitary
defect'' and ``significant deficiency,'' there are differences in the
required timeframes for responding to them (see 40 CFR 141.403(a)(5)
and 142.16(b)(1)(ii), and Sec. Sec.  141.859(b)(3) and (b)(4) of the
RTCR). It might therefore be more confusing to use only one term for
the requirements of the GWR and RTCR, as suggested by some commenters.
    In addition, the GWR only applies to ground water systems. Relying
only on the corrective action provisions of the GWR (triggered by a
fecal indicator-positive sample) will leave out those systems not
covered by the GWR. Also, these GWR provisions are focused on the
source water. Since contamination is intermittent and can be from a
location other than the source water, the assessment and corrective
action provisions in the RTCR will help to better address other types
of defects.
    As noted in the preamble to the proposed RTCR, nothing in the RTCR
is intended to limit the existing authorities of States under other
regulations.
4. Seasonal Systems
    a. Provisions. EPA is finalizing the definition of seasonal system
as ``a non-community water system that is not operated on a year-round
basis and starts up and shuts down at the beginning and end of each
operating season.''
    The advisory committee recognized that seasonal systems have unique
characteristics that make them susceptible to contamination. As their
name implies, seasonal systems are not operated year-round. The
depressurizing and dewatering of the water system, as often occurs with
the temporary shutdown of the system, present opportunities for
contamination to enter or spread through the distribution system. For
example, loss of pressure after a system's shutdown can lead to
intrusion of contaminants. Even a system that remains pressurized may
be subject to water quality degradation due to stagnant water or loss
of disinfectant residual. Microbial growth prior to start-up can result
in biofilm formation, which can lead to the accumulation of
contaminants. These systems are also more susceptible to contamination
due to changes in the conditions of the source water (such as variable
contaminant loading due to increased septic tank or septic field use),
the seasonal nature of the demand, and the stress that the system
experiences. As a result, the Agency is establishing a definition for
seasonal systems and setting forth provisions that mitigate the risk
associated with the unique characteristics of this type of system (see
section III.C.1.f of this preamble, Seasonal systems, for requirements
for seasonal systems). The advisory committee recommended that such
provisions pertain to seasonal systems.
    The definition of seasonal system that EPA is promulgating with
this final rule is different from the definition proposed in July 2010
(USEPA 2010a, 75 FR 40926, July 14, 2010), which is ``a non-community
water system that is operated in three or fewer calendar quarters per
calendar year.'' As discussed in the preamble to the proposed rule, EPA
was aware of the limitations of the proposed definition that could lead
to less public health protection and less effective and more
complicated implementation. EPA gave the example of a system that is
operated from March to October. Such a system would operate in all four
calendar quarters and therefore would not be considered a seasonal
system according to the proposed definition, but would nonetheless be
subject to the same possibility of distribution system contamination as
a seasonal system operated from April to November (i.e., in only three
calendar quarters). To address limitations such as this, EPA
specifically requested comment on the proposed definition of a seasonal
system. The change in the definition from the proposed rule is based on
the comments received. Specific requirements (e.g., monitoring, start-
up procedure, etc.) for seasonal systems that address the issues
associated with such systems are discussed in section III.C.1.f,
Seasonal systems, and III.C.2.c, Seasonal systems, of this preamble.
    The definition does not include intermittent systems, such as those
that are open year-round but are not operated continuously (e.g., a
church open only on Saturdays and Sundays). It also does not include
systems that operate year-round but may shut down part of their
distribution system for part of the year (e.g., parts of the
distribution system that serve a factory that is open only certain
times of the year). Since these systems might be subject to the same
type of risks as seasonal systems, States may want to consider whether
to establish requirements that will mitigate the risks associated with
their operation.
    b. Key issues raised. EPA received many responses regarding the
definition of a seasonal system. Many commenters suggested addressing
the issue of depressurization and dewatering in the definition. They
suggested that the important risk factor is not the number of quarters
the system is in operation but rather the closure and the
depressurization and/or dewatering of the distribution system. Other
commenters expressed concern about contamination associated with lack
of water movement and loss of disinfectant

residual even in a pressurized system. Although the definition of
seasonal systems does not directly address these issues, seasonal
systems are required to perform start-up procedures (which may include
disinfection, flushing, and coliform sampling) prior to serving water
to the public. See section III.C.1.f of this preamble, Seasonal
systems, for a discussion of the requirements for seasonal systems. EPA
believes that it is important for a seasonal system to perform start-up
procedures to mitigate the public health risks associated with stagnant
water and the depressurization and/or dewatering of the distribution
system. Hence, failure to perform start-up procedures will result in a
treatment technique violation. See section III.F.b of this preamble,
Coliform treatment technique violation, for additional discussion on
this violation.
    Since it is possible and perhaps likely that some systems may keep
the distribution system pressurized while out of season, EPA has
included an additional provision in the RTCR whereby a State can exempt
any seasonal system from some or all of the requirements for seasonal
systems if the entire distribution system remains pressurized during
the entire period that the system is not operating (see Sec. Sec.
141.854(i)(3), 141.856(a)(4)(ii), and 141.857(a)(4)(ii) of the RTCR).
In providing such exemption, the State should conclude that public
health protection is maintained. However, a seasonal system monitoring
less frequently than monthly must still monitor during the vulnerable
period designated by the State. See section III.C.1.f of this preamble,
Seasonal systems, for additional discussion.
    Some commenters suggested that seasonal systems be defined by the
number of days, months, or quarters they are not in operation, e.g.,
30, 60, or 90 consecutive days, three or more consecutive months, one
full calendar quarter, etc. While such a change could address some of
EPA's concerns, it does not address the potential for contamination
associated with lack of operation and loss of pressure.

B. Rule Construct: MCLG and MCL for E. coli and Coliform Treatment
Technique

1. MCLG and MCL
    a. Requirements. Under the final RTCR, EPA is eliminating the MCLG
for total coliforms (including fecal coliforms) and the MCL for total
coliforms. EPA is also establishing an MCLG of zero and an MCL for E.
coli. The MCL for E. coli is based on the monitoring results for total
coliforms and E. coli. A system is in compliance with the E. coli MCL
unless any of the following conditions occur:
     A system has an E. coli-positive repeat sample following a
total coliform-positive routine sample; or
     A routine sample is E. coli-positive and one of its
associated repeat samples is total coliform-positive; or
     A system fails to test for E. coli when any repeat sample
tests positive for total coliforms; or
     A system fails to take all required repeat samples
following a routine sample that is positive for E. coli.
    Although not explicitly stated, as a logical consequence of the
second condition, a system also violates the MCL when an E. coli-
positive routine sample is followed by an E. coli-positive repeat
sample because E. coli bacteria are a subset of total coliforms.
    EPA is establishing an MCLG of zero for E. coli and removing the
current MCLG of zero for total coliforms (including fecal coliforms)
because E. coli is a more specific indicator of fecal contamination and
potential harmful pathogens in drinking water than are total coliforms
(including fecal coliforms). These requirements were part of the July
2010 proposed rule (USEPA 2010a, 75 FR 40926, July 14, 2010) and are
unchanged in the final RTCR. See section III.A.2 of the preamble to the
proposed RTCR, MCLG and MCL for E. coli, and coliform treatment
technique, for further discussion on the MCLG, MCL, and treatment
technique requirements.
    b. Key issues raised. The majority of the commenters supported
EPA's proposal to remove the MCLG and MCL for total coliforms
(including fecal coliforms) and to establish an MCLG and MCL for E.
coli.
    However, there were some who commented that removing the MCLG and
MCL for total coliforms will result in backsliding in public health
protection. These commenters stated that the elimination of the non-
acute MCL violation removes a strong incentive for water systems to
perform proactive maintenance and operations activities to maintain
distribution system water quality and avoid MCL violations and
subsequent public notice to customers. EPA disagrees. EPA and the
advisory committee decided that removing the MCLG and MCL for total
coliforms is appropriate. SDWA section 1412(b)(3)(A)(i) directs EPA to
use ``the best available, peer-reviewed science and supporting studies
conducted in accordance with sound and objective science practices'' in
conducting the risk assessment when promulgating an NPDWR. In 1989, EPA
set an MCLG of zero for total coliforms. Since the promulgation of the
1989 TCR, a better understanding of the nature of total coliforms,
especially fecal coliforms, has become available. Many of the organisms
detected by total coliform and fecal coliform methods are not of fecal
origin and do not have any direct public health implications (Edberg et
al. 2000). Total coliforms may, however, indicate the presence of a
pathway by which fecal contamination can occur; thus, total coliforms
are instead used as part of a treatment technique requirement, which is
discussed in more detail in the next section and in section III.E of
this preamble, Coliform Treatment Technique. Inclusion of the MCLG and
MCL for total coliforms is not supported by the available science and
would be contrary to SDWA section 1412(b)(3)(A)(i).
    Commenters agreed with EPA's proposal to eliminate the provisions
on fecal coliforms. Therefore, fecal coliforms will no longer be used
in the RTCR and all analytical methods used to detect for fecal
coliforms are also removed from the rule. For a discussion on
analytical methods, see section III.I of this preamble, Analytical
Methods.
2. Coliform Treatment Technique
    a. Requirements. EPA is establishing a treatment technique that
will require a PWS to conduct an assessment of its system and, when
necessary, perform corrective actions in response to trigger conditions
that indicate a possible pathway of contamination into the system. The
treatment technique requirements are the same as those in the proposed
RTCR. A PWS that exceeds a specified frequency of total coliform
occurrence must conduct a Level 1 or Level 2 assessment to determine if
any sanitary defect exists and, if found, to correct the sanitary
defect. As discussed earlier, the MCLG and MCL for total coliforms are
removed. The conditions that defined a non-acute MCL violation under
the 1989 TCR are now used to trigger a system to conduct an assessment
of the system. A discussion of the treatment technique requirements,
i.e., the triggers, the levels of assessment, the completion of the
assessment form, etc., can be found in section III.E of this preamble,
Coliform Treatment Technique.
    b. Key issues raised. The majority of the commenters supported the
change from a total coliform non-acute MCL to a treatment technique
requirement. However, some commenters disagreed with the change. They
stated that the treatment technique construct will not work for small
NCWSs since they typically do not treat their water, have

no certified operator, and have limited or no distribution system. They
noted that since systems with limited or no distribution system do not
have the extensive network of piping and service connections and other
elements that comprise a typical distribution system, the treatment
technique construct, which the commenters considered as focusing on the
distribution system, will not work. These commenters suggested that for
systems with limited or no distribution system, the focus should be on
the source, and therefore, the requirements of the GWR should be
sufficient. They suggested that the total coliform MCL should be
retained for these systems because the treatment technique requirements
will be too complicated for these systems to comply with, resulting in
more non-compliance, more burden on the State, and likely less public
health protection.
    EPA disagrees that the treatment technique construct will not work
for small NCWSs. The requirement to assess the system after a trigger
consists of looking at all of the elements that might have affected the
quality of the distributed water, including not only the distribution
system but also the source and the treatment process. Although some
small systems have limited or no distribution system, they can still
have parts of their system (e.g., building plumbing, or buried piping
at a campground) that are vulnerable to contamination, such as that
introduced by a cross-connection or infiltration. In addition, relying
only on the corrective action provisions of the GWR will leave out
those systems not covered by the GWR, or in cases of positive results,
systems where corrective action under the GWR is not immediately
required by the State. For example, total coliform-positive repeat
samples do not trigger any action under the GWR, even if those samples
are also triggered source water samples. Also, a State may require
additional source samples instead of a corrective action after the
first fecal indicator positive sample (see 40 CFR 141.402(a)(3)). In
addition, some small NCWSs with limited or no distribution system use
surface water. Finally, the GWR provisions are focused on the source
water. Since contamination is intermittent and can be from a location
other than the source water, the assessment and corrective action
provisions in the RTCR will help address other types of defects.
    EPA understands that there will be implementation challenges during
the first few years of the rule implementation, especially for small
PWSs. However, as systems with limited or no distribution system are
simple systems, the assessments should also be relatively simple. There
is nothing in the RTCR that prohibits the States from conducting
assessments that integrate the requirements of the GWR and RTCR where
appropriate (see section III.E of this preamble, Coliform Treatment
Technique, for a discussion of the coliform treatment technique). EPA
encourages States to make any necessary modifications to their
regulations to make the most efficient use of limited State resources
and to better integrate these rules for systems with little-to-no
distribution system, provided that the revisions satisfy the primacy
requirements for both the GWR and the RTCR. Also, EPA plans to develop
guidance manuals specifically for small systems to help them comply
with the RTCR. EPA is also working to update the Safe Drinking Water
Information System (SDWIS) to include the requirements of the RTCR and
have SDWIS ready in advance of the compliance date for the rule.
    As discussed earlier, EPA believes that the treatment technique
requirements are more protective of public health because they require
a system to take preventive actions to address problems. This is a
change from just issuing a PN and conducting additional monitoring
under the 1989 TCR to proactively doing an assessment to determine the
cause of the possible contamination under the RTCR and performing
corrective action where needed.

C. Monitoring

1. Requirements
    a. Requirements that apply to all PWSs. As with the 1989 TCR, the
RTCR requires all PWSs to collect and test samples for total coliforms
and E. coli according to a sample siting plan and schedule specific to
the system. PWSs must collect the samples at regular intervals
throughout the month, except systems that use only ground water and
serve 4,900 or fewer people may collect all required samples on a
single day if they are taken from different sites.
    Under the RTCR, all PWSs are still required to take repeat samples
within 24 hours of learning of any routine monitoring sample that is
total coliform-positive. PWSs must comply with the repeat monitoring
requirements and E. coli analytical requirement, discussed in detail in
section III.D of this preamble, Repeat Samples. All samples taken for
RTCR compliance (routine and repeat) may occur at a customer's
premises, dedicated sampling station, or other designated compliance
sampling location.
    EPA notes that a system must still take the required minimum number
of samples even if it has had an E. coli MCL violation or has exceeded
the coliform treatment triggers before the end of the monitoring
compliance period. For example, if a system has an E. coli MCL
violation after taking 10 of the 40 required routine monthly samples,
the system must continue routine total coliform monitoring, analyze any
total coliform-positive samples for E. coli, and take one round of
repeat samples following any total coliform-positive routine sample.
    Under the RTCR, systems' sample siting plans must include routine
and repeat sample sites and any sampling points necessary to meet the
Ground Water Rule (GWR) requirements. As with the 1989 TCR, the sample
siting plan is subject to State review and revision.
    The repeat sample sites may be alternative monitoring locations
that the PWS is proposing to use instead of the repeat sample locations
that are within five connections upstream and downstream of the
original sampling location that tested total coliform-positive. The PWS
must demonstrate to the State's satisfaction that the alternative
monitoring locations are representative of a pathway for contamination
into the distribution system (for example, near a storage tank), and
that the sample siting plan remains representative of the water quality
in the distribution system. Systems may elect to specify either
alternative fixed locations or criteria for selecting their repeat
sampling locations on a situational basis in a standard operating
procedure (SOP), which is part of the sample siting plan. The State may
determine that monitoring at the entry point to the distribution system
(especially for undisinfected ground water systems) is effective to
differentiate between potential source water and distribution problems.
The use of alternative monitoring locations or an SOP does not require
prior State approval but systems are required to submit to their
primacy agencies their proposed alternative locations. States can
modify and revise these locations or the SOP as needed. Additional
discussion about the alternative monitoring locations can be found in
section III.D of this preamble, Repeat Samples.
    Monitoring locations that serve both as a repeat sampling location
and a triggered source water monitoring location for the GWR (i.e.,
locations for dual purpose sampling) must also be included in the
sample siting plan. These locations need to be approved by

the State before the PWS can use them. For more discussion on the dual
purpose sampling, see section III.D of this preamble, Repeat Samples.
    Under the RTCR, PWSs may take more than the minimum required number
of routine samples and must include the results in calculating whether
the total coliform treatment technique trigger for conducting an
assessment has been exceeded, but only if the samples are taken in
accordance with the sample siting plan and are representative of water
throughout the distribution system (see section III.E of this preamble,
Coliform Treatment Technique, for a discussion on the coliform
treatment technique requirements).
    Under the RTCR, EPA is not making substantive changes to the
requirements of the TCR for (1) special purpose samples, and (2)
invalidation of total coliform samples.
    New systems that begin operation on or after the compliance date of
the RTCR must comply with the routine monitoring frequency established
by the RTCR for their system size and type beginning in their first
month of operation.
    The following are the monitoring requirements for different
categories of systems.
    b. Ground water NCWSs serving <= 1,000 people. i. Routine
monitoring. The RTCR requires ground water NCWS serving 1,000 or fewer
people to routinely monitor each quarter for total coliforms and E.
coli except that systems can transition into RTCR at their 1989 TCR
monitoring frequency as discussed in further detail in the next
section, and there are provisions under which the monitoring frequency
may be reduced or increased. Seasonal systems under this category must
routinely monitor every month that they are in operation (see section
III.C.1.f of this preamble, Seasonal systems, for additional discussion
on seasonal system requirements).
    ii. Transition to the RTCR. The RTCR requires all ground water
NCWSs serving 1,000 or fewer people, including seasonal systems, to
continue with their 1989 TCR monitoring schedules as of the compliance
date of the RTCR, unless or until any of the conditions for increased
monitoring discussed later in this section are triggered on or after
the compliance date, or unless otherwise directed by the State as a
result of the special monitoring evaluation conducted under a sanitary
survey or at any other time the State believes that the sampling the
system is conducting may not be adequate. In addition, systems on
annual monitoring, including seasonal systems, must have an initial
annual site visit by the State within one year of the compliance date
and an annual site visit each calendar year thereafter to remain on
annual monitoring. Systems may substitute a voluntary Level 2
assessment by a party approved by the State for the annual site visit
in any given year. The periodic sanitary survey may be used to meet the
requirement for an annual site visit for the year in which the sanitary
survey was completed.
    After the compliance date of the final RTCR, during each sanitary
survey the State must perform a special monitoring evaluation to review
the status of the water system, including the distribution system, to
determine whether the system is on an appropriate RTCR monitoring
schedule and modify the monitoring schedule as necessary. States must
evaluate system factors such as the pertinent water quality and
compliance history, the establishment and maintenance of contamination
barriers, and other appropriate protections, and validate the
appropriateness of the water system's existing RTCR monitoring schedule
and modify as necessary. For seasonal systems on quarterly or annual
monitoring, this evaluation must also include review of the approved
sample siting plan, which designates the time period(s) for monitoring
based on site-specific considerations (such as during periods of
highest demand or highest vulnerability to contamination). The system
must collect compliance samples during these designated time periods.
    iii. Reduced monitoring. The State has the discretion to reduce the
monitoring frequency for well-operated ground water NCWSs from the
quarterly routine monitoring to no less than annual monitoring, if the
water system can demonstrate that it meets the criteria for reduced
monitoring provided in this section.
    To be eligible to qualify for and remain on annual monitoring after
the compliance date, a ground water NCWS serving 1,000 or fewer people
must meet all of the following criteria:
     The system must have a clean compliance history (no MCL
violations or monitoring violations under the 1989 TCR and/or RTCR, no
Level 1 or Level 2 trigger exceedances or treatment technique
violations under the RTCR) for a minimum of 12 months. (For a more
detailed discussion on Level 1 and Level 2 triggers, see section III.E
of this preamble, Coliform Treatment Technique);
     The most recent sanitary survey shows the system is free
of sanitary defects, has a protected water source and meets approved
construction standards; and
     An initial site visit by the State within the last 12
months to qualify for reduced annual monitoring, and recurring annual
site visits to stay on reduced annual monitoring; and correction of all
identified sanitary defects. A voluntary Level 2 assessment by a party
approved by the State may be substituted for the State annual site
visit in any given year.
    iv. Increased monitoring. Ground water NCWS serving 1,000 or fewer
people on quarterly or annual monitoring must begin monthly monitoring
the month after any of the following events occurs:
     The system triggers a Level 2 assessment or two Level 1
assessments in a rolling 12 month period;
     The system has an E. coli MCL violation;
     The system has a coliform treatment technique violation
(for example, if the system fails to conduct a Level 1 assessment or
correct for sanitary defects if required to do so);
     The system on quarterly monitoring has two RTCR monitoring
violations; or
     The system has one RTCR monitoring violation and triggers
a Level 1 assessment in a rolling 12-month period.
    EPA added the last condition by which a ground water NCWS serving
<= 1,000 people can be triggered into increased monitoring to improve
the internal consistency of these triggers, given that these NCWSs
monitor less frequently in general, and given the added flexibility for
States to elect not to count monitoring violations at TNCWS toward
triggers to increased monitoring as described in the next paragraph.
Since either two Level 1 assessments or two RTCR monitoring violations
in a rolling 12-month period triggers increased monitoring, EPA
believes it is appropriate for one of each of these events to also
trigger increased monitoring for these NCWSs. See section III.E.1 of
this preamble, Coliform treatment technique triggers, for a discussion
of coliform treatment technique triggers.
    EPA also added flexibility to allow States to elect to not count
TNCWS monitoring violations in determining whether the trigger for
increased monitoring has been exceeded, but only if the missed sample
is collected no later than the end of the next monitoring period. The
system must collect the make-up sample in a different week than the
routine sample for the next monitoring period and should collect the
sample as soon as possible during the next monitoring period. This

provision applies only for routine samples. The TNCWS would still incur
a monitoring violation and must follow the other requirements
associated with such violation (e.g., public notification and
reporting). This provision is added in response to comments received by
EPA. See section III.C.2.b of this preamble, Ground water NCWSs serving
<= 1,000 people, for additional discussion of this provision.
    Ground water NCWS serving 1,000 or fewer people on annual
monitoring must begin quarterly monitoring the month after the
following event occurs:
     The system on annual monitoring has one RTCR monitoring
violation.
    This is a change from the proposed rule requirement where the event
would have triggered the system to go to monthly monitoring instead of
quarterly monitoring. This change is further discussed in section
III.C.2.b of this preamble, Ground water NCWSs serving <= 1,000 people.
    The system must continue monthly or quarterly monitoring until the
requirements in this section for returning to quarterly or annual
monitoring are met.
    v. Requirements for returning to quarterly monitoring. To be
eligible to return from increased monthly monitoring to quarterly
monitoring, ground water NCWSs serving 1,000 or fewer people must meet
all of the following criteria:
     Within the last 12 months, the system must have a
completed sanitary survey or a site visit by the State or a voluntary
Level 2 assessment by a party approved by the State. The system is free
of sanitary defects, and has a protected water source; and
     The system has a clean RTCR compliance history (no E. coli
MCL violations, Level 1 or 2 triggers, coliform treatment technique
violations or monitoring violations) for a minimum of 12 months.
    For TNCWSs, the State may elect not to count monitoring violations
towards the requirement of a clean compliance history (as presented in
the last bullet) if the missed sample is collected no later than the
end of the next monitoring period. This applies only for routine
samples. The TNCWS would still incur a monitoring violation and must
follow the other requirements associated with such violation (e.g.,
public notification and reporting). See section III.C.2.b of this
preamble, Ground water NCWSs serving <= 1,000 people, for additional
discussion about this provision.
    vi. Requirements for returning to reduced annual monitoring. To be
eligible to return from increased monthly monitoring to reduced annual
monitoring, the system must meet the criteria to return to routine
quarterly monitoring plus the following criteria:
     An annual site visit (recurring) by the State and
correction of all identified sanitary defects. An annual voluntary
Level 2 assessment may be substituted for the State annual site visit
in any given year; and
     The system must have in place or adopt one or more
additional enhancements to the water system barriers to contamination
as approved by the State. These measures could include but are not
limited to the following:

--Cross connection control, as approved by the State.
--An operator certified by an appropriate State certification program,
which may include regular visits by a circuit rider certified by an
appropriate State certification program.
--Continuous disinfection entering the distribution system and a
residual in the distribution system in accordance with criteria
specified by the State.
--Maintenance of at least a 4-log inactivation or removal of viruses
each day of the month based on daily monitoring as specified in the GWR
(with allowance for a 4-hour exception).
--Other equivalent enhancements to water system barriers to
contamination as approved by the State.
    vii. Additional routine monitoring. All systems collecting samples
on a quarterly or annual frequency must conduct additional routine
monitoring following a single total coliform-positive sample (with or
without a Level 1 trigger event). The additional routine monitoring
consists of three samples in the month following the total coliform-
positive sample at routine monitoring locations identified in the
sample siting plan. This is a change from the 1989 TCR additional
routine monitoring requirement of taking a total of five samples the
month following a total coliform-positive sample for systems that take
four or fewer samples per month. Consistent with the 1989 TCR, the
State may waive the additional routine monitoring requirement if:
     The State, or an agent approved by the State, performs a
site visit before the end of the next month the system provides water
to the public. Although a sanitary survey need not be performed, the
site visit must be sufficiently detailed to allow the State to
determine whether additional monitoring and/or any corrective action is
needed. The State cannot approve an employee of the system to perform
this site visit, even if the employee is an agent approved by the State
to perform sanitary surveys or RTCR assessments.
     The State has determined why the sample was total
coliform-positive and establishes that the system has corrected the
problem or will correct the problem before the end of the next month
the system serves water to the public. In this case, the State must
document this decision to waive the following month's additional
monitoring requirement in writing, have it approved and signed by the
supervisor of the State official who recommends such a decision, and
make this document available to the EPA and public. The written
documentation must describe the specific cause of the total coliform-
positive sample and what action the system has taken and/or will take
to correct this problem.
     The State may not waive the requirement to collect three
additional routine samples the next month in which the system provides
water to the public solely on the grounds that all repeat samples are
total coliform-negative. If the State determines that the system has
corrected the contamination problem before the system takes the set of
repeat samples required in Sec.  141.858, and all repeat samples were
total coliform-negative, the State may waive the requirement for
additional routine monitoring the next month.
    All additional routine samples are included in determining
compliance with the MCL and coliform treatment technique requirements.
    c. Ground water CWSs serving <= 1,000 people. i. Routine
monitoring. The RTCR requires ground water CWSs serving 1,000 or fewer
people to routinely monitor at least once each month for total
coliforms and E. coli except that systems can transition into RTCR at
their 1989 TCR monitoring frequency as discussed in further detail in
the next section, and there are provisions under which the sampling
frequency may be reduced by the State.
    The State may reduce the monitoring frequency for ground water CWS
from the monthly routine monitoring to quarterly reduced monitoring if
the water system can demonstrate that it meets the criteria for reduced
monitoring provided later in this section.
    ii. Transition to the RTCR. All ground water CWSs serving 1,000 or
fewer people continue with their 1989 TCR monitoring schedules unless
or until any of the increased monitoring requirements in this section
occur or as directed by the State.
    After the compliance date of the final RTCR, the State must
determine

whether the system is on an appropriate monitoring schedule by
performing a special monitoring evaluation during each sanitary survey
to review the status of the PWS, including the distribution system. The
first such evaluation must be conducted during the first scheduled
sanitary survey after the effective date of the rule; a system may
remain on its 1989 TCR monitoring schedule until this time unless it is
triggered into more frequent monitoring. After its first evaluation,
the State may allow the system to remain on its 1989 TCR monitoring
schedule as long as the system meets the conditions for doing so. The
State must evaluate system factors such as the pertinent water quality
and compliance history, the establishment and maintenance of barriers
to contamination, and other appropriate protections to validate the
water system's existing monitoring schedule or require more frequent
monitoring.
    iii. Reduced monitoring. The State has the flexibility to reduce
the monitoring frequency for well-operated ground water CWS from the
monthly routine monitoring to no less than quarterly monitoring if the
water system can demonstrate that it meets the criteria for reduced
monitoring provided in this section.
    To be eligible to change from monthly to quarterly reduced
monitoring after the compliance date, ground water CWSs serving 1,000
or fewer people must be in compliance with any State-certified operator
provisions and meet each of the following criteria:
     The system must have a clean compliance history (no MCL
violations or monitoring violations under the TCR and/or RTCR, no Level
1 or Level 2 trigger exceedances or treatment technique violations
under the RTCR) for a minimum of 12 months;
     The most recent sanitary survey shows the system is free
of sanitary defects (or has an approved plan and schedule to correct
them and is in compliance with the plan and the schedule), has a
protected water source, and meets approved construction standards; and
     The system must meet at least one of the following
criteria:

--An annual site visit by the State or an annual voluntary Level 2
assessment by a party approved by the State or meeting criteria
established by the State and correction of all identified sanitary
defects (or an approved plan and schedule to correct them and is in
compliance with the plan and schedule).
--A cross connection control program, as approved by the State.
--Continuous disinfection entering the distribution system and a
residual in the distribution system in accordance with criteria
specified by the State.
--Demonstration of maintenance of at least a 4-log inactivation or
removal of viruses each day of the month based on daily monitoring as
specified in the GWR (with allowance for a 4-hour exception) (USEPA
2006c, 71 FR 65574, November 8, 2006).
--Other equivalent enhancements to water system barriers to
contamination as approved by the State.

    iv. Requirements for returning to monthly monitoring. When a system
on quarterly monitoring experiences any of the following events the
system must begin monthly monitoring the month after the event occurs:
     System triggers a Level 2 assessment or two Level 1
assessments in a rolling 12-month period.
     System has an E. coli MCL violation.
     System has a coliform treatment technique violation (e.g.,
fails to conduct a Level 1 or Level 2 assessment or to correct for a
sanitary defect if required to do so).
     System has two routine RTCR monitoring violations in a
rolling 12-month period.

The system must continue monthly monitoring until all the reduced
monitoring requirements discussed previously in this section are met. A
system that loses its certified operator must also return to monthly
monitoring the month following the loss.
    v. Additional routine monitoring. Ground water CWSs serving <=
1,000 people collecting samples on a quarterly frequency must conduct
additional routine monitoring following a single total coliform-
positive sample (with or without a Level 1 trigger event), similar to
the additional monitoring requirements for ground water NCWS serving <=
1,000 people. See section III.C.1.b.vii of this preamble, Additional
routine monitoring, for a discussion of the additional routine
monitoring requirements.
    d. Subpart H systems serving <= 1,000 people. The monitoring
requirements for subpart H systems of this part (PWSs supplied by a
surface water source or by a ground water under the direct influence of
surface water (GWUDI) source) serving 1,000 or fewer people remain the
same as under the 1989 TCR (see Sec.  141.856). These systems are not
eligible for reduced monitoring. In addition, the rule requires all
seasonal systems, on and after the compliance date of the final RTCR,
to demonstrate completion of a State-approved start-up procedure (see
section III.C.1.f of this preamble, Seasonal systems, for additional
discussion on seasonal system requirements).
    e. PWSs serving  1,000 people. The monitoring
requirements for PWSs serving more than 1,000 people remain the same as
under the 1989 TCR (see Sec.  141.857), with the exception of the
applicable revisions to the repeat sampling locations provided in Sec.
141.858 and to the additional routine monitoring provisions. Systems on
monthly monitoring are not required to take additional routine samples
the month following a total coliform-positive sample, as recommended by
the advisory committee (see section III.A.3.b.ii(g) of the preamble to
the proposed RTCR, Additional routine monitoring, for an explanation of
this change from the 1989 TCR). Consistent with the 1989 TCR, systems
serving > 1,000 people are not eligible for reduced monitoring. In
addition, the rule requires all seasonal systems, on and after the
compliance date of the final RTCR, to demonstrate completion of a
State-approved start-up procedure (see section III.C.1.f of this
preamble, Seasonal systems, for additional discussion on seasonal
system requirements).
    f. Seasonal systems. Since seasonal systems are a subset of NCWSs,
they are subject to the requirements of the particular NCWS size
category they fall under (e.g., seasonal systems using ground water and
serving <= 1,000 people are subject to the requirements of ground water
NCWS serving <= 1,000 people, or seasonal systems using surface water
and serving <= 1,000 people are subject to the requirements of subpart
H systems serving <= 1,000 people, and so on), unless otherwise noted.
The RTCR is promulgating requirements specific to seasonal systems to
mitigate the risk associated with the unique characteristics of this
type of systems (see section III.A.4 of this preamble, Seasonal
systems, for additional discussion about seasonal systems). One of the
provisions is the requirement that all seasonal systems must
demonstrate completion of a State-approved start-up procedure prior to
serving water to the public on and after the compliance date of the
final RTCR each time they start up the system. The start-up procedure
may include a requirement for a start-up sample prior to serving water
to the public.
    Under the RTCR, all seasonal systems are required to take at least
one routine sample per month for total coliforms and E. coli during the
months that they are in operation, unless the sampling

frequency has been reduced by the State under the RTCR. Seasonal
systems serving > 1,000 people have the same monitoring frequency as
other PWSs serving > 1,000 people (see Sec.  141.857 of the RTCR) and
it cannot be reduced. However, seasonal systems serving <= 1,000 people
that are not on monthly monitoring by the compliance date of the RTCR
may continue with their existing 1989 TCR monitoring frequency
afterwards, unless or until any of the conditions for increased
monitoring discussed previously in section III.C.1.b.iv of this
preamble, Increased monitoring, are triggered on or after the
compliance date, or as directed by the State. To continue on their
existing 1989 TCR monitoring frequency, seasonal systems on less than
monthly monitoring at the compliance date of the RTCR must have an
approved sample siting plan that designates the time period for
monitoring based on site-specific considerations (e.g., during periods
of highest demand or highest vulnerability to contamination). The
system must collect compliance samples during this time period.
Seasonal systems on annual monitoring frequency are required to have a
recurring annual site visit by the State (or an annual voluntary Level
2 assessment by a party approved by the State) to remain on annual
monitoring.
    Only seasonal systems using ground water and serving <= 1,000
people are eligible for reduced monitoring. To be newly eligible for
reduced monitoring after the compliance date, they must meet the
following criteria:
     The system must have an approved sample siting plan that
designates the time period for monitoring based on site-specific
considerations (e.g., during periods of highest demand or highest
vulnerability to contamination). The system must collect compliance
samples during this time period; and
     To be eligible for reduced quarterly monitoring, the
system must also meet all the reduced monitoring criteria discussed in
section III.C.1.b.v of this preamble, Requirements for returning to
quarterly monitoring, and provided in Sec.  141.854(g) of the RTCR.
     To be eligible for reduced annual monitoring, the system
must also meet all the reduced monitoring criteria discussed in section
III.C.1.b.vi of this preamble, Requirements for returning to reduced
annual monitoring, and provided in Sec.  141.854(h) of the RTCR.
    The State may exempt any seasonal system from some or all of the
requirements for seasonal systems (e.g., performing start-up
procedures) if the entire distribution system remains pressurized
during the entire period that the system is not operating. However,
systems that monitor less frequently than monthly must still monitor
during the time period designated in their approved sample siting plan.
    g. Consecutive systems. EPA did not identify any issues regarding
consecutive systems in the RTCR. Consecutive systems must monitor for
total coliforms at a frequency based on the population served by the
consecutive system and the source water type of the wholesale system.
In instances where it is justified to treat two or more distribution
systems as a single system for monitoring purposes, 40 CFR 141.29
allows the State to modify the monitoring requirements for the combined
distribution system. Any modifications to the monitoring requirements
must be approved by EPA. The State may not, however, modify the
compliance requirements. The RTCR is not modifying the provisions of 40
CFR 141.29. When conducting assessment and corrective action under the
RTCR, wholesalers and consecutive systems should cooperate as directed
by the State and conduct assessment and corrective action based on the
location of the positive sample results, the potential pathways of
distribution system contamination, and the sanitary defects identified.
2. Key Issues Raised
    a. Sample siting plans. The majority of the comments EPA received
supported the proposal that sample siting plans be subject to State
review and revision instead of requiring State approval. The advisory
committee recommended that States review and revise sample siting plans
consistent with current practice and that the State develops and
implements a process to ensure the adequacy of sample siting plans. EPA
also received comments that requiring State approval of sample siting
plans will be an additional burden to the States. Considering these
comments and the recommendation of the advisory committee, EPA,
therefore, is not changing the requirement regarding State review and
revision of the sample siting plan in most instances. There are,
however, instances where it is necessary for the State to review and
approve elements of the sample siting plan, and other instances where
the need for State approval is left to State discretion. For example,
seasonal systems on less than monthly monitoring must have an approved
sample siting plan that designates the time period for collecting the
sample(s) as discussed previously in section III.C.1.f of this
preamble, Seasonal systems. On the other hand, for systems that want to
establish repeat sampling locations other than the within-five-
connections-upstream-and-downstream of the total coliform-positive
sample, the system must submit the siting plan for review and the State
may modify the sampling locations as needed, but State approval is not
required by the RTCR, as discussed in section III.D of this preamble,
Repeat Samples.
    EPA received comment that supported the use of dedicated sampling
locations. Although not specifically addressed this practice is already
in use by some States and systems under the 1989 TCR. As discussed in
the proposed RTCR, EPA is specifically allowing the use of dedicated
sampling stations for the following reasons:
     To reduce potential contamination of the sampling taps.
Utilities will have more control to prevent contamination of the
sampling tap by preventing its use by unauthorized persons and allowing
no routine use of the tap except for sampling.
     To facilitate access to sampling taps. Currently systems
may be constrained by where they sample, e.g., only at public buildings
or in certain individual customer's house.
     To improve sampling representation of the distribution
system. Allowing dedicated sampling taps in areas where systems have
not been able to gain access will facilitate better sampling
representation of the distribution system.
    b. Ground water NCWSs serving <= 1,000 people. EPA received
comments regarding the monitoring requirements for small ground water
NCWSs. Many of the commenters agreed with the requirements proposed
while some commenters suggested that systems should not be allowed to
monitor less than monthly.
    The advisory committee recommended that the routine monitoring
frequency for ground water NCWSs serving 1,000 or fewer people remain
at quarterly monitoring as provided in the 1989 TCR. EPA believes that
quarterly monitoring carried out in conjunction with the assessment and
corrective action requirements would maintain or improve public health
protection without increasing sampling costs over the 1989 TCR
requirements. The advisory committee also recognized that current
sampling costs are not insignificant for small systems, and wanted to
allow reduced monitoring for well-performing systems under the more
specific and rigorous criteria described previously in sections
III.C.1.b.iii, Reduced monitoring, and III.C.1.c.iii, Reduced
monitoring, of this preamble. To continue to provide adequate health

protection, systems on reduced monitoring must adhere to criteria that
ensure that barriers are in place and are effective. Furthermore,
systems with problems that may indicate poor system integrity,
maintenance, or operations, or systems that fail to monitor, are
triggered into more frequent monitoring. This approach leverages the
limited resources of small ground water NCWSs and of States, so that
well-operated systems can minimize their costs and States can focus
their resources on systems needing the greatest attention, such as
systems with problems or vulnerabilities.
    EPA requested comment in the proposed rule on whether to require
NTNCWSs to comply with the CWS requirements (as they are in other rules
such as disinfection byproduct (DBP) rules) since NTNCWSs serve the
same people over time and include populations that may be at greater
risk (e.g., schools, hospitals, daycare centers).
    EPA received comments both in agreement and disagreement with this
approach. Those who disagreed stated that such requirement would result
in disproportionate impact on NTNCWS, since these systems are small
systems with limited resources. One commenter said that the 1989 TCR
has been in effect for decades now and there have been no adverse
health effect impacts by not having NTNCWSs comply with CWS
requirements.
    Considering the comments EPA received, the Agency is not requiring
NTNCWSs to comply with CWS requirements under the RTCR. However, EPA
recommends that States consider the population served at NTNCWSs,
especially those that serve sensitive subpopulations such as schools,
hospitals, and daycare centers, when they decide on an appropriate
monitoring frequency. EPA is aware that some States are already doing
so and suggests that other States consider the same.
    EPA received comments that the criteria for returning to reduced
monitoring are overly strict, including a suggestion that the
requirement to have an additional barrier enhancement to return to
annual monitoring is too burdensome and costly. Some commenters stated
that systems that are triggered into increased monitoring will be
unlikely to return to reduced monitoring. Another commenter suggested
that a system should be able to return to reduced monitoring sooner
than 12 months.
    EPA continues to believe that for a system to be able to monitor
only once a year, it should be able to demonstrate that it has the
ability to continually deliver safe water by ensuring that barriers are
in place to protect against contamination. A system that has been
triggered into increased monitoring has failed in some way to
demonstrate that it has those barriers in place. The requirements to
return to reduced monitoring are intended to show that the system has
made the long-term commitment and provided the necessary additional
barriers to eliminate the vulnerability to contamination that triggered
the increased monitoring in the first place. EPA believes that the
requirements for returning to reduced monitoring are not impossible to
meet but require an appropriate level of effort over at least 12 months
to show the commitment and ability to deliver safe water.
    EPA received comments regarding monitoring violations as a trigger
for increased monitoring and as part of the criteria for returning to
reduced monitoring. EPA heard from States with large numbers of NCWSs
that including monitoring violations as a trigger for increased
monitoring and as part of the criteria for reduced monitoring will make
the RTCR difficult to implement in their States. NCWSs, especially
TNCWSs, pose unique challenges to rule compliance as they typically do
not have the resources that CWSs have and providing water is not their
primary business. Commenters suggested that triggering a NCWS into
increased monitoring because of just one or two missed samples is not
appropriate and will burden the State with compliance and enforcement
tracking. They indicated that this will shift limited State resources
away from oversight activities for CWSs that serve large populations to
compliance and enforcement activities for NCWSs that serve small
populations, resulting in decreases in public health protection. The
commenters also concluded that once a system is triggered into
increased monitoring, it would not be able to qualify for reduced
monitoring because it would not be able to meet the requirements for
clean compliance history (e.g., no monitoring violations).
    EPA recognizes the burden on States that may result from
implementing the increased and reduced monitoring provisions of the
RTCR. EPA is therefore providing States the flexibility to not count
monitoring violations towards eligibility for remaining on quarterly
monitoring or for returning to quarterly monitoring as long as a make-
up sample is collected by the end of the next monitoring period. This
flexibility only applies to TNCWSs and only for routine samples. The
State cannot use this flexibility to qualify a system for annual
monitoring. When exercising the flexibility about whether to count a
monitoring violation towards eligibility for reduced monitoring, the
State may find it appropriate to also consider the system's history of
monitoring violations. The TNCWSs would still incur a monitoring
violation and must comply with the other associated requirements after
such violation (e.g., public notification and reporting).
    In the proposed rule, a NCWS on annual monitoring with one RTCR
monitoring violation is triggered into monthly monitoring. Some
commenters expressed concern that many systems on annual monitoring
will be triggered to monthly monitoring because of just one missed
sample. The commenters stated that this was unreasonable considering
that these systems typically do not have the resources that CWSs have,
such as a certified operator. These systems typically experience
frequent staff shortages or turnover that result in missed samples.
Having these systems do monthly monitoring would require significant
tracking and enforcement activities on the part of the State.
    To address this concern, EPA has changed the consequence of having
one RTCR monitoring violation for systems on annual monitoring. Instead
of having to go to monthly monitoring, the system now moves to
quarterly monitoring. EPA also believes that the annual site visit by
the State, and the fact that some States conduct and/or pay for the
annual monitoring, reduces the likelihood that systems on annual
monitoring will miss samples and be triggered to increase to quarterly
monitoring, so that PWS and State resource needs are not likely to
significantly increase because of this requirement. EPA is not changing
the consequence of exceeding the other triggers for increased
monitoring; systems that experienced any of the other events in section
III.C.1.b.iv of this preamble, Increased monitoring, will need to
monitor monthly instead of quarterly. Systems can go back to annual
monitoring by meeting the criteria for reduced monitoring.
    EPA requested comment on whether daily chlorine residual
measurements should be one of the criteria for reduced monitoring. EPA
received comments that said that it should not be a criterion. Some
commenters expressed concern that one missed measurement might be a
basis for being bumped to increased monitoring. One commenter suggested
giving the State the discretion to either allow or not allow it as a
criterion. Section 141.854(h)(2)(iii) of the RTCR specifies that one of
the

enhancements to water system barriers to contamination is continuous
disinfection entering the distribution system and a residual in the
distribution system in accordance with criteria specified by the State.
States are given the discretion to decide how they want to implement
this criterion based on site-specific considerations. States may want
to require daily measurement of chlorine residual to demonstrate
continuous disinfection.
    One commenter expressed concern that a reduction in the number of
additional routine samples (i.e., from five to three) reduces the
likelihood of detecting both total coliforms and E. coli. The advisory
committee recommended that it is appropriate to drop from five to three
samples the following month to reduce monitoring costs while still
maintaining a substantial likelihood of identifying a problem if a
problem persists. EPA and the advisory committee recognized that a
reduction in the number of samples taken could also mean a reduction in
the number of positive samples found. However, EPA and the advisory
committee concluded that the new assessment and corrective action
provisions of the RTCR lead to a rule that is more protective of public
health and to improvement in water quality despite the reductions in
the number of samples taken. The Final RTCR EA occurrence modeling
results support this conclusion, as they predict that more E. coli MCL
violations will be prevented and total coliform and E. coli-positive
hit rates will decrease when assessment and corrective action occur.
See chapter 6 of the Final RTCR EA (USEPA 2012a) for more details.
    c. Seasonal systems. EPA received comments that disagreed with the
routine monthly monitoring frequency for seasonal systems. The
commenters suggested that requiring a start-up procedure is the
essential element and having seasonal systems monitor quarterly like
all other NCWSs should be adequate. Other commenters agreed with
monthly monitoring.
    As discussed in section III.A.4 of this preamble, Seasonal systems,
seasonal systems are more susceptible to contamination due to changes
in the conditions of the source water during the period the system is
in operation. Such changes include variable contaminant loading due to
increased septic tank or septic field use, the seasonal nature of the
demand, and the stress the system may experience. Because of the risk
factors, the advisory committee decided that more frequent monitoring
is appropriate for these systems, with the possibility of going on
reduced monitoring if they meet certain criteria. EPA concurs with the
advisory committee assessment and the final rule maintains the proposed
routine monthly monitoring frequency, when they are in operation, for
seasonal systems.
    One commenter said that a regular sampling schedule is more easily
achieved and more practical than identifying vulnerable time periods as
these periods can vary from year to year. EPA believes that a system
that will monitor less frequently than monthly should sample based on
site-specific considerations (e.g., during periods of high demand or
highest vulnerability of contamination). This increases the probability
of detecting a possible contamination; hence, measures can be taken to
address the possible contamination before it becomes a public health
threat.
    One commenter suggested that start-up procedures must include
flushing, disinfection, re-flushing to eliminate disinfectant residual,
and taking a sample prior to serving water to the public. EPA is not
requiring specific practices regarding the start-up procedure. States
are given the flexibility to determine what start-up procedures are
appropriate for a particular system based on its site-specific
considerations and must describe their process for determining start-up
procedures in their primacy application. EPA recommends that States
require seasonal systems to take a sample as part of the required
start-up procedures. Systems must allow sufficient time for completing
start-up procedures (including receiving sample results) and notifying
the State as required prior to serving water to the public.

D. Repeat Samples

1. Requirements
    Under the RTCR, all PWSs must take at least three repeat samples
for each routine sample that tested positive for total coliforms. This
is a change from the 1989 TCR requirements where systems serving 1,000
or fewer people must collect at least four repeat samples while the
rest of the systems must collect three repeat samples.
    As discussed in the preamble to the proposed RTCR, EPA believes
that sampling again immediately after determining that a sample is
positive (i.e., conducting repeat sampling) increases the likelihood of
identifying the source and/or nature of the possible contamination.
Analyses conducted by EPA indicated that once a total coliform-positive
is found, there is a much greater likelihood of finding another total
coliform-positive within a short period of time of the initial finding
(see page 40939 of the Federal Register (FR) notice for the proposed
RTCR (USEPA 2010a, 75 FR 40926, July 14, 2010) for more discussion on
the analyses done by EPA regarding repeat samples). Repeat sampling
(when it is total coliform-positive) can indicate a current pathway for
potential external contamination into the distribution system. EPA
recommends that States work with PWSs and laboratories to facilitate
timely notification through the most expeditious method (e.g., phone,
fax, or email) to ensure that repeat samples are taken in a timely
manner.
    The repeat monitoring requirements of the RTCR are essentially the
same as the requirements of the 1989 TCR, except for some new
provisions promulgated by the RTCR to provide flexibility to States and
PWSs. The following requirements are not changing under the RTCR:
     PWSs must collect the repeat samples within 24-hours of
being notified that their routine sample is total coliform-positive.
     The State can extend the 24-hour limit on a case-by-case
basis. EPA is providing flexibility to this provision as discussed
later in this section.
     The State cannot waive the requirement for a system to
collect repeat samples.
     In addition to taking repeat samples, PWSs must test each
routine total coliform-positive sample for E. coli. They must also test
any repeat total coliform-positive sample for E. coli. If E. coli is
present, the system must notify the State the same day it learns of the
positive result, or by the end of the next business day if the State
office is closed and the State does not have either an after-hours
phone line or an alternative notification procedure.
     The State has the discretion to allow the system to forgo
E. coli testing in cases where the system assumes that the total
coliform-positive sample is E. coli-positive. If the State allows a
system to forgo E. coli testing, the system must still notify the State
and comply with the E. coli MCL requirements specified in Sec.
141.858.
     The system must collect at least one repeat sample from
the sampling tap where the original total coliform-positive sample was
taken. Unless different locations are specified in its sample siting
plan (this is a new provision of the RTCR and is discussed later in
this section), the system must also collect at least one repeat sample
at a tap within five service connections upstream, and at least one
repeat sample at a tap within five service connections

downstream of the original sampling site. The State may waive the
requirement to collect at least one repeat sample upstream or
downstream of the original sampling site if the total coliform-positive
sample is at the end of the distribution system, or one service
connection away from the end of the distribution system. EPA notes that
it is the location of the repeat sample that is waived, not the
required number of repeat samples. A PWS still needs to take the
required repeat sample(s) elsewhere in the distribution system if it is
unable to do so upstream or downstream of the original sampling site.
     Systems must collect all repeat samples on the same day.
The State may allow systems with a single service connection to collect
the required set of repeat samples over a three-day period or to
collect a larger volume repeat sample(s) in one or more sample
containers of any size, as long as the total volume collected is at
least 300 milliliters (ml).
     Systems must collect an additional set of repeat samples
for each total coliform-positive repeat sample. As with the original
set of repeat samples, the system must collect the additional repeat
samples within 24 hours of being notified of the positive result,
unless the State extends the time limit. The system must repeat this
process until either total coliforms are not detected in one complete
set of repeat samples or, as the RTCR is adding, the system determines
that the coliform treatment technique trigger has been exceeded and
notifies the State. After a trigger (see section III.E, of this
preamble, Coliform Treatment Technique) is reached, the system is
required to conduct only one round of repeat monitoring after each
total coliform-positive or E. coli-positive routine sample. If a
trigger is reached as a result of a repeat sample being total coliform-
or E. coli-positive, no further repeat monitoring related to that
sample is necessary.
     A subsequent routine sample, which is within five service
connections of the initial routine sample and is collected after an
initial routine sample but before the system learns the initial routine
sample is total coliform-positive, may count as a repeat sample
instead.
     A ground water system with a single well serving 1,000 or
fewer people may still use a repeat sample collected from a ground
water source to meet both the repeat monitoring requirements of the
RTCR and the triggered source monitoring requirements of the GWR (i.e.,
a dual purpose sample). Modifications to this provision under the RTCR
are discussed later in this section.
    As mentioned previously, the RTCR adds some new provisions to the
repeat monitoring requirements to provide flexibility to the States and
PWSs. One of these changes is the additional flexibility provided to
States regarding the waiver or the extension of the 24-hour limit for a
PWS to collect repeat samples. States are given the option to describe
in their primacy application the criteria they will use to waive or
extend the 24-hour limit instead of making the decisions on a case-by-
case basis. This is discussed further in section V of this preamble,
State Implementation.
    Another change is the use of alternative monitoring locations. As
discussed in section III.C of this preamble, Monitoring, the PWS may
propose alternative repeat monitoring locations that are expected to
better characterize or identify pathways of contamination into the
distribution system. Systems may elect to specify either alternative
fixed locations or criteria for selecting their repeat sampling
locations on a situational basis in a standard operating procedure
(SOP), which is part of the sample siting plan. By allowing systems to
specify criteria for selecting their repeat sampling locations in their
SOP instead of setting fixed repeat sampling locations, systems can
provide a more flexible and more protective response. The system can
focus the repeat samples at locations that will best verify and
determine the extent of potential contamination of the distribution
system based on specific situations. For discussion on additional
requirements for alternative monitoring locations, see section III.C of
this preamble, Monitoring.
    There are also some modifications to the dual purpose sampling
allowed under the GWR and 1989 TCR. Ground water systems required to
conduct triggered source monitoring under the GWR must take ground
water source samples in addition to the repeat samples required by the
RTCR. However, a ground water system serving 1,000 or fewer people may
use a repeat sample collected from a ground water source to meet both
the repeat monitoring requirements of the RTCR and the source water
monitoring requirements of the GWR (i.e., a dual purpose sample), but
only if the State approves the use of a single sample to meet both rule
requirements and the use of E. coli as a fecal indicator for source
water monitoring. If the sample is E. coli-positive, the system
violates the E. coli MCL under the RTCR and must also comply with the
GWR requirements following a fecal indicator-positive sample. These
provisions are consistent with the GWR.
    If a system with a limited number of monitoring locations (such as
a system with only one service connection or a campground with only one
tap) takes more than one repeat sample at the triggered source water
monitoring location, the system may reduce the number of additional
source water samples by the number of repeat samples taken at that
location that were not E. coli-positive. For example, if a system takes
two dual purpose samples and one is E. coli-positive and the other is
E. coli-negative, the system has an E. coli MCL violation under the
RTCR and is required to take four additional source water samples,
rather than five, under the GWR (see 40 CFR 141.402(a)(3)). If the
system takes more than one of these repeat samples at the triggered
source water monitoring location and has more than one repeat sample
that is E. coli-positive at the triggered source water monitoring
location, then the system would have both an E. coli MCL violation
under the RTCR and a second fecal indicator-positive source sample
under the GWR. The system would then need to also comply with the GWR
treatment technique requirements under 40 CFR 141.403.
    Results of all routine and repeat samples not invalidated by the
State must be used to determine whether the coliform treatment
technique trigger has been exceeded (see section III.E of this
preamble, Coliform Treatment Technique, for a discussion of the
coliform treatment technique triggers).
2. Key Issues Raised
    A majority of the commenters supported the change from four to
three repeat samples for systems serving 1,000 or fewer people.
However, one commenter stated that decreasing the number of repeat
samples would also lessen the likelihood of detecting total coliforms
and E. coli. EPA explained the analysis that EPA has done to support
the reduction in the number of repeat samples in the preamble to the
proposed RTCR. In that analysis, using the Six-Year Review 2 data
(USEPA 2010c), EPA showed that if the number of required repeats were
reduced from four to three, there would still be almost as many
(approximately 94 percent) situations leading to an assessment being
triggered for the system. See section III.A.4 of the preamble to the
proposed RTCR, Repeat Samples, for a detailed discussion of EPA's
analysis on the reduction of the number of repeat

samples. Although dropping the required number of repeat samples from
four to three means that some fraction of triggered assessments may be
missed, the other provisions of the RTCR compensate for that change
and, taken as a whole, the provisions of the RTCR provide for greater
protection of public health. One such provision includes enhanced
consequences for monitoring violations. For example, systems that do
not take all of their repeat samples under the RTCR are triggered to
conduct a Level 1 assessment. This permits an increase in public health
protection over the 1989 TCR because PWSs are required to assess their
systems when lack of required monitoring creates a situation where the
PWS does not properly know whether it is vulnerable to contamination.
Moreover, because of the substantial cost of this potential
consequence, systems would be more likely to take all of their required
repeat samples in the first place (see section III.E of this preamble,
Coliform Treatment Technique, for additional discussion on the coliform
treatment technique triggers).