[Federal Register: July 14, 2010 (Volume 75, Number 134)]
[Proposed Rules]
[Page 40925-41016]
[DOCID:fr14jy10-21]

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Part III

Environmental Protection Agency

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40 CFR Parts 141 and 142

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

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 141 and 142

[EPA-HQ-OW-2008-0878; FRL-9166-8]
RIN 2040-AD94

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed Rule.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is
proposing revisions to the 1989 Total Coliform Rule. The proposed
Revised Total Coliform Rule offers a meaningful opportunity for greater
public health protection beyond the current Total Coliform Rule. The
proposed 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
proposal also updates provisions in other rules that reference
analytical methods and other requirements in the current TCR (e.g.,
Public Notification and Ground Water Rules). These proposed revisions
are in accordance with the Safe Drinking Water Act as amended, which
requires EPA to review and revise, as appropriate, each national
primary drinking water regulation promulgated under the Safe Drinking
Water Act not less often than every six years. As with the current
Total Coliform Rule, the proposed Revised Total Coliform Rule applies
to all public water systems.

DATES: Comments must be received on or before September 13, 2010.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2008-0878, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov.
Follow the on-line instructions for submitting comments.
     Mail: Water Docket, Environmental Protection Agency,
Mailcode: 4101T, 1200 Pennsylvania Ave., NW., Washington, DC 20460,
Attention Docket ID No. EPA-HQ-OW-2008-0878. In addition, please mail a
copy of your comments on the information collection provisions to the
Office of Information and Regulatory Affairs, Office of Management and
Budget (OMB), Attn: Desk Officer for EPA, 725 17th St., NW.,
Washington, DC 20503.
     Hand Delivery: EPA Docket Center, (EPA/DC) EPA West, Room
B102, 1301 Constitution Ave., NW., Washington, DC. Such deliveries are
only accepted during the Docket's normal hours of operation, and
special arrangements should be made for deliveries of boxed
information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2008-
0878. EPA's policy is that all comments received will be included in
the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://
www.regulations.gov, or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket, visit the EPA Docket Center homepage at http://www.epa.gov/
epahome/dockets.htm.
    Docket: All documents in the docket are listed in the http://
www.regulations.gov index. Although listed in the index, some
information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statue. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Water Docket, EPA
Docket Center, EPA/DC, EPA West, Room B102, 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>; e-mail 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 proposed Revised Total
Coliform Rule (RTCR) are all public water systems (PWSs). Regulated
categories and entities include the following:

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                                                Examples of regulated
                 Category                             entities
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Industry..................................  Privately-owned community
                                             water systems (CWSs),
                                             transient non-community
                                             water systems (TNCWSs), and
                                             non-transient non-community
                                             water systems (NTNCWSs).
State, Tribal, and local governments......  Publicly-owned CWSs, TNCWSs,
                                             and NTNCWSs.
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    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.  141.850(b)
of this proposed 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 http://www.epa.gov/
safewater/disinfection/tcr/. For other related information, see
preceding discussion on docket.

Abbreviations Used in This Document

ADWR Airline Drinking Water Rule
AGI Acute Gastrointestinal Illness
AIDS Acquired Immune Deficiency Syndrome
AIP Agreement in Principle
AWWA American Water Works Association
ATP Alternative Test Procedure
AWOP Area Wide Optimization Program
BAT Best Available Technology
C Celsius
CA Corrective Action
CBI Confidential Business Information
CCR Consumer Confidence Report
CDC Centers for Disease Control and Prevention
CFR Code of Federal Regulations
COI Cost of Illness
CWS Community Water System
DBPs Disinfection Byproducts
DWC Drinking Water Committee
EA Economic Analysis
EC E. coli
EC-MUG EC Medium with MUG
EPA United States Environmental Protection Agency
ETV Environmental Technology Verification
FR Federal Register
GW Ground Water
GWR Ground Water Rule
GWS Ground Water System
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
MOU Memorandum of Understanding
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
PN Public Notification
PWS Public Water System
RFA Regulatory Flexibility Act
RICP Research and Information Collection Partnership
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
SW Surface Water
SWTR Surface Water Treatment Rule
TC Total Coliforms
TCR Total Coliform Rule
TCRDSAC Total Coliform Rule/Distribution System Advisory Committee
TNCWS Transient Non-Community Water System
T&C Technology and Cost
US United States
UV Ultraviolet Radiation
WRF Water Research Foundation

Table of Contents

I. General Information
    A. Regulated Categories and Entities
    B. Copies of This Document and Other Related Information
II. Background
    A. Statutory Authority
    B. Total Coliform Rule Distribution System Advisory Committee
(TCRDSAC)
    C. Other Outreach Processes
    D. Public Health Concerns Addressed by the Proposed Revised
Total Coliform Rule
    1. Public health concerns, fecal contamination, and waterborne
pathogens
    2. Indicators
    3. Occurrence of fecal contamination and waterborne pathogens
III. Proposed Revised Total Coliform Rule
    A. Proposed Rule Provisions and Rationale
    1. Terms used in the proposed RTCR
    2. MCLG and MCL for E. coli, and coliform treatment technique
    3. Monitoring
    4. Repeat samples
    5. Treatment technique requirements
    6. Violations
    7. Providing notification and information to the public
    8. Reporting and recordkeeping requirements for systems
    9. Analytical methods
    B. Proposed Compliance Date
    C. Links to Other Drinking Water Rule Requirements
    1. SWTR, Stage 1 and Stage 2 DBPRs, ADWR
    2. GWR
    3. Sanitary surveys
    D. Best Available Technology (BAT)
    1. Provisions
    2. EPA's rationale
    3. Request for comment
    E. Variances and Exemptions
    1. Provisions
    2. EPA's rationale
    3. Request for comment
    F. Request for Comment on Other Issues Related to the Proposed
RTCR
    1. Consistency between the proposed RTCR and the GWR
    2. Storage tank inspection and cleaning
    3. States under EPA direct implementation
    G. Limitations to the Public Comment on the Proposed RTCR
IV. State Implementation
    A. State Special Primacy Requirements
    B. State Recordkeeping Requirements
    C. State Reporting Requirements
    D. Interim Primacy
    E. Request for Comment
V. Distribution System Research and Information Collection
Activities
    A. Research and Information Collection Partnership
    B. Distribution System Optimization Activities
    C. Request for Comment
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 public water systems serving 4,100 or fewer
people
    2. Model used for public water systems serving more than 4,100
people
    D. Baseline Profiles
    E. Anticipated Benefits of the Proposed RTCR
    1. Relative risk analysis
    2. Changes in violation rates and corrective actions
    3. Nonquantifiable benefits
    F. Anticipated Costs of the Proposed RTCR
    1. Total annualized present value costs
    2. PWS costs
    3. State costs
    4. Nonquantifiable costs
    G. Potential Impact of the Proposed 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
Proposed RTCR
    1. Inputs and their uncertainties
    2. Sensitivity analysis
    M. Benefit Cost Determination for the Proposed RTCR
    N. Request for Comment on the Economic Analysis
VII. Statutory and Executive Order Review
    A. Executive Order 12866: Regulatory Planning and 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. Impacts on Sensitive Subpopulations as Required by Section
1412(b)(3)(C)(i) of the 1996 Amendments of the Safe Drinking Water
Act (SDWA)
    M. Plain Language
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) at least once every six years (SDWA section
1412(b)(9), 42 U.S.C. 300g-1(b)(9)). In 2003, EPA completed its review
of the Total Coliform Rule (TCR) 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 (also
referred to as the ``current TCR'').

B. Total Coliform Rule Distribution System Advisory Committee (TCRDSAC)

    In June 2007, EPA established the Total Coliform Rule/Distribution
System Advisory Committee (``TCRDSAC'' or ``the advisory committee'')
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
distribution systems (USEPA 2007a, 72 FR 35869, June 29, 2007). The
decision to include a review of distribution system issues was made, in
part, to address recommendations made by the Stage 2 Microbial and
Disinfection Byproducts Federal Advisory Committee in December 2000
(USEPA 2000b, 65 FR 83015, December 29, 2000). The TCRDSAC used
available information to analyze options for revisions to the TCR. The
TCRDSAC also considered research and information needed to better
understand and address public health risks from contamination of
distribution systems.
    The advisory committee consisted of representatives of EPA, State
and local public health and regulatory agencies, consumer
organizations, environmental organizations, local elected officials,
Indian Tribes, and drinking water suppliers. A technical workgroup was
also formed to provide the advisory committee with necessary technical
support and analysis to facilitate the committee's discussions. The
advisory committee met on 13 occasions between July 2007 and September
2008. All advisory committee members agreed to and signed the final
Agreement in Principle (AIP) in September 2008. All of the
recommendations of the advisory committee are found in the signed AIP.
Pursuant to the AIP, EPA agreed to propose revisions to the TCR that,
to the maximum extent consistent with EPA's legal obligations, have the
same substance and effect as the elements of the AIP. Each party
represented on the advisory committee agreed in the AIP not to take any
action to inhibit the adoption and implementation of final rule(s) to
the extent it and the corresponding preamble have the same substance
and effect as the elements of the AIP. EPA also agreed in the AIP to
develop a Research and Information Collection Partnership (RICP) to
``inform and support the drinking water community in developing future
national risk management decisions pertaining to drinking water
distribution systems'' by providing ``a formal process for systematic
planning, implementation, analysis, and communication of distribution
system research and information collection'' (USEPA 2008c). A
discussion of the RICP can be found in section V of this preamble. The
AIP and details about the advisory committee can be found at EPA's Web
site at: http://www.epa.gov/safewater/disinfection/tcr/regulation_
revisions.html.
    In addition to the outreach mentioned above, EPA agreed to engage
in various future stakeholder meetings at least annually, to which all
advisory committee members and the public at large would be invited. In
April 2009, EPA held its first annual stakeholder meeting to provide
draft proposed regulation updates and an opportunity for stakeholders
to provide feedback on the development of the proposed RTCR.

C. Other Outreach Processes

    In addition to consulting with the advisory committee, EPA engaged
in several other activities as part of the Agency's outreach to
stakeholders in developing the proposed RTCR. EPA held a technical
workshop in Washington, DC, from January 30 to February 1, 2007, to
discuss available information on the current TCR and available
information regarding risks in distribution systems in support of
revisions to the TCR. Other EPA outreach activities, namely the
National Drinking Water Advisory Council consultation, Science Advisory
Board consultation, and the Tribal consultation, are discussed in
section VII of this preamble.

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

1. Public Health Concerns, Fecal Contamination, and Waterborne
Pathogens
    The proposed 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, reduced kidney function, hypertension and
reactive arthritis can result from infection by a waterborne agent
(Clark et al. 2008).
    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 which are 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.
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. 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 current 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 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.
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 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. 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). 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 hemolytic uremic syndrome
(HUS) in the United States (Rangel et al. 2005). The U.S. Centers for
Disease Control and Prevention (CDC) estimates that there are 73,000
cases of illness each year in the U.S. 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 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 (or one with
amoebic meningoencephalitis) 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).
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 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 epidemic, endemic 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. Proposed Revised Total Coliform Rule

    The proposed RTCR maintains and strengthens the objectives of the
current

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 proposed revision
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 proposed
RTCR compared to the current 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 proposed
RTCR:
     MCLG and MCL for E. coli and coliform treatment technique
for protection against potential fecal contamination. The proposed RTCR
establishes a maximum contaminant level goal (MCLG) and maximum
contaminant level (MCL) for E. coli. It 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, will require 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.A.2 of this preamble for a
detailed discussion on the MCLG, MCL, and treatment technique
requirements.
     Monitoring. As with the current 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 proposed RTCR must continue to be
representative of the water throughout the distribution system. Under
the proposed 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 current
TCR of five connections upstream and downstream of the total coliform-
positive sample location.
    As with the current TCR, the proposed RTCR allows reduced
monitoring for some small ground water systems. The proposed RTCR is
expected to improve public health protection compared to the current
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 TCR 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 proposed RTCR requires
increased monitoring for high-risk systems that meet certain criteria
such as unacceptable compliance history under the RTCR. The proposed
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 proposed RTCR requires systems on a quarterly or annual
monitoring frequency (applicable only to ground water systems serving
1,000 or fewer people) to conduct additional routine monitoring the
month following one or more total coliform-positive samples. Under the
proposed RTCR, systems must collect at least three routine samples
during the next month, unless the State waives the additional routine
monitoring. This is a reduction in the required number of additional
routine samples from the current 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 current TCR requires all systems serving 1,000 or fewer people
to collect at least four repeat samples while PWSs serving 1,000 people
or greater to collect three repeat samples. The proposed rule requires
three repeat samples after a routine total coliform-positive sample,
regardless of the system type and size.
    See sections III.A.3 and III.A.4 of this preamble for detailed
discussions of the routine monitoring and repeat sampling requirements
of the proposed RTCR.
     Seasonal systems. The proposed RTCR establishes monitoring
requirements for seasonal systems for the first time. 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. Seasonal systems must
demonstrate completion of a State-approved start-up procedure. In
addition, they must designate the time period(s) for monitoring based
on site-specific considerations (such as during periods of highest
demand or highest vulnerability to contamination) in their State-
approved sample siting plan. See section III.A.3 of this preamble for a
detailed discussion of 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 a simple self-assessment (Level 1)
or a more detailed assessment (Level 2) depending on the severity and
frequency of contamination. The system is responsible for correcting
any sanitary defect(s) found through either a Level 1 or Level 2
assessment. See section III.A.5 of this preamble for more discussion of
the treatment technique requirement of the proposed RTCR.
     Violations and public notification. The proposed 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 proposed RTCR also modifies the public
notification and Consumer Confidence Report language to reflect the
construct of the proposed rule. See sections III.A.6 and III.A.7 of
this preamble for detailed discussions of violations and public
notification under the proposed RTCR.
     Transition to the RTCR. The proposed RTCR allows all
systems to transition to the new rule at their current TCR monitoring
frequency, including systems on reduced monitoring under the current
TCR. States will then evaluate the monitoring frequency during each
sanitary survey conducted after the compliance effective date of the
RTCR. This process reduces State burden by not requiring the State to
determine appropriate monitoring frequency at the same time as when the
State is trying to adopt primacy, develop policies, and train their own
staff and the PWSs in the State.
    The provisions of the proposed RTCR are contained in the new 40 CFR
part 141 subpart Y, superseding 40 CFR 141.21 beginning three years
following the publication of the final revised rule.

A. Proposed Rule Provisions and Rationale

1. Terms used in the proposed RTCR
    a. Provisions. i. Clean compliance history. For the purposes of the
proposed RTCR, EPA is proposing to define ``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.
    ii. Sanitary defect. EPA is proposing to define ``sanitary defect''
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''
(USEPA 2008c).
    iii. Seasonal systems. EPA is proposing to define a seasonal system
as a non-community water system that is operated in three or fewer
calendar quarters per calendar year.
    b. EPA's rationale. i. Clean compliance history. EPA is proposing a
definition of ``clean compliance history'' because without a
definition, the use of the phrase could result in multiple
interpretations. Clean compliance history is one of the criteria a
system must meet to be eligible for reduced monitoring. The advisory
committee recommended this definition (USEPA 2008c, AIP p. 10).
    ii. Sanitary defect. The advisory committee recommended the
definition of sanitary defect. The proposed RTCR takes a more
preventive approach to protect public health by establishing a
framework for the assessment of public water systems to identify
sanitary defects and to correct them as appropriate. The first part of
the proposed definition of a ``sanitary defect'' focuses on 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.
    Sanitary defect is a term specific to the proposed RTCR assessment
and corrective action provisions. Sanitary defects are not intended to
be linked directly to ``significant deficiencies'' under the Interim
Enhanced Surface Water Treatment Rule (IESWTR) (USEPA 1998b, 63 FR
69389, December 16, 1998) and Ground Water Rule (GWR) (USEPA 2006c, 71
FR 65574, November 8, 2006), although some problems could meet either
definition. Nothing in this proposed rule is intended to limit the
existing authorities of States under other regulations.
    The following is a list of examples of sanitary defects and defects
in the distribution system coliform monitoring practices (USEPA 2008c,
AIP Appendix Y, p. 41).
    Examples of sanitary defects:
     Cross connection and backflow issues such as a required
backflow prevention device not in place or not operating properly; or
an unprotected cross connection found.
     Operator issues such as failure to follow standard
operating procedures (SOPs) that protect distribution system integrity
and sanitary conditions.
     Distribution system issues such as inadequate inspection
and maintenance of the distribution system; loss of distribution system
integrity such as main breaks; failure to maintain adequate pressure;
improper flushing operations; improper construction of new, replaced,
or renovated lines; inadequate disinfection during and after repair/
replacement activities; or inability to maintain required residual
throughout the distribution system.
     Storage issues such as overflow, vents, hatches, and other
penetrations not properly configured, screened, or sealed; inadequate
maintenance of storage facilities; or inadequate disinfection during
and after repair/replacement activities.
     Disinfection issues such as inability to maintain required
residual throughout the distribution system.
    iii. Seasonal systems. Seasonal systems fall under the broader
category of non-community water systems (NCWS) and therefore are
subject to provisions applicable to that category of systems. However,
seasonal systems have unique characteristics and timetables that make
them particularly susceptible to contamination. Seasonal systems
represent a special case in that the shut down and start-up of the
water system present opportunities for contamination to enter or spread
through the distribution system. For example, loss of pressure after a
system's shut down can lead to intrusion of contaminants. 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. The advisory committee
recommended that such provisions pertain to seasonal systems. See
section III.A.3 of this preamble for specific provisions that seasonal
systems must meet.
    c. Request for comment. EPA requests comment on the proposed
definitions and whether they work within the construct of the proposed
RTCR. Specifically, EPA requests comment on the proposed definition of
seasonal systems. The advisory committee recommended that seasonal
systems be identified and be subject to additional regulatory
requirements because the shutdown and startup of the system presents
opportunities for contaminants to enter or spread through the
distribution system. These results are possible in any system that
shuts down and does not maintain adequate pressure throughout the
distribution system. The AIP describes a seasonal system as ``one which
operates less than four calendar quarters per year'' (USEPA 2008c). EPA
has interpreted this to mean that a seasonal system is one which is
shut down for at least one full calendar quarter (i.e., it operates in
three or fewer calendar quarters). EPA requests comment on whether this
proposed definition of ``seasonal system'' is adequate to address the
concern that motivated the advisory committee's recommendation and is
consistent with its intent. For example, a system that operated from
March to October would operate in all four calendar quarters and would
not be considered a seasonal system, but would be subject to the same
possibility of distribution system intrusion as a seasonal system that
operated April to November (i.e., in only three calendar quarters).
Should EPA modify the definition to address this issue? If so, how
should the definition be modified? Should systems that close for some
specified period (e.g., 30 days, 60 days, 90 days) be subject to
seasonal system requirements? What should that specified period be?
    Systems that operate intermittently (e.g., only on weekends or only
when a camp is open) may also be subject to distribution system
contamination due to lack of adequate pressure. Should this be
addressed? If so, how should it be addressed--through regulation,
guidance, or some other approach? Is

there a specific shutdown time that should be considered for
intermittent systems in developing the approach and determining which
systems should be included?
    In addition to the public health benefits associated with these
requirements, EPA is aware of the burden that States will have in
determining which systems must comply and in tracking compliance.
Therefore, EPA requests comment on ways to reduce State burden and
facilitate implementation of seasonal system provisions.
2. MCLG and MCL for E. coli, and Coliform Treatment Technique
    a. Provisions. The current TCR established a maximum contaminant
level goal (MCLG) of zero for total coliforms (including fecal
coliforms and E. coli) and an MCL for total coliforms. EPA is proposing
in the RTCR to eliminate the MCLG for total coliforms (including fecal
coliforms) and the MCL for total coliforms. Under the proposed RTCR,
EPA establishes an MCLG of zero and an MCL for E. coli and a treatment
technique for coliform. The proposed 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.
    The proposed MCL is similar to the criteria that define the
conditions (if exceeded) when a Tier 1 acute MCL violation occurs under
the current TCR but with two modifications. First, the proposed MCL
excludes fecal coliforms. Second, the proposed MCL also includes an
additional condition by which a system violates the MCL, namely failing
to collect all repeat samples following an initial E. coli-positive
sample. 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 are a subset of total coliforms. EPA is also
proposing a coliform treatment technique, which uses total coliforms
and E. coli as indicators of a possible breach in the distribution
system that could lead to fecal contamination.
    b. EPA's rationale. i. Inclusion of MCLG for E. coli and removal of
MCLG for total coliforms (including fecal coliforms). EPA is proposing
in the RTCR to include an MCLG of zero for E. coli and to remove the
current MCLG of zero for total coliforms (including fecal coliforms).
This is 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). 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 implication. See also
the discussion of fecal coliforms in section III.A.9 of this preamble.
New information has become available since promulgation of the current
TCR in 1989 that indicates that measurement of fecal coliforms
sometimes detects organisms that may not have any connection to fecal
contamination (Edberg et al. 2000). An MCLG of zero for E. coli is more
appropriate than an MCLG of zero for total coliforms (including fecal
coliforms) since E. coli is a more specific indicator of the presence
of fecal contamination.
    Total coliforms (including fecal coliforms) do not in and of
themselves pose a public health risk, but they may indicate the
presence of a pathway by which fecal contamination can occur.
Therefore, the removal of the MCLG for total coliforms (including fecal
coliforms) would prevent possible public confusion as a result of
attributing greater public health significance to the presence of total
coliforms than is warranted. EPA believes that the removal of the MCLG
for total coliforms, along with the other proposed changes discussed in
the succeeding paragraphs, leads to a rule that is more protective of
public health, and is less confusing to the public. The proposed MCLG
of zero for E. coli and the removal of the MCLG for total coliforms
(including fecal coliforms) are also consistent with the recommendation
made by the advisory committee in the AIP.
    ii. Inclusion of MCL for E. coli and removal of MCLs for total
coliforms and fecal coliforms. EPA is proposing to include in the RTCR
an MCL for E. coli because approved analytical methods continue to be
available to measure the presence of E. coli in water samples, i.e.,
the presence of E. coli is technologically feasible to ascertain.
Violation of the proposed MCL for E. coli signifies fecal contamination
occurrence and a possible high risk of exposure to pathogens. EPA is
proposing to eliminate the MCLs for total coliforms and fecal coliforms
because under the proposal there is no longer an MCLG for either total
coliforms or fecal coliforms, for the reasons explained earlier. The
proposed MCL for E. coli is consistent with the recommendation made by
the advisory committee in the AIP.
    iii. Coliform treatment technique. The 1996 SDWA amendments
authorize EPA to promulgate a treatment technique in lieu of an MCL if
EPA determines that ``it is not economically or technologically
feasible to ascertain the level of the contaminant'' (SDWA
1412(b)(7)(A)). While it is technologically feasible to ascertain
levels of E. coli (i.e., analytical methods continue to be available to
measure the presence of E. coli in water samples), because of the
intermittent nature of fecal contamination, it is not economically
feasible to ascertain the level of E. coli occurrence below which the
water may be deemed safe. This is because it is not economically
feasible to monitor E. coli with sufficient frequency to ensure such
safety.
    Because total coliform bacteria are part of the soil ecosystem,
positive samples are indicators of fecal contaminant entry into
drinking water via a pathway from the soil. EPA is proposing a coliform
treatment technique, supplemental to directly measuring E. coli, to
provide additional protection against fecal contamination. Under the
proposed coliform treatment technique, as specified in the AIP, total
coliform-positive samples, in the absence of E. coli, are still
indicators of an E. coli or other fecal contaminant pathway.
    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(s) exist(s) and, if found, to correct the
defect(s). In addition, under the proposed treatment technique
requirements, a PWS that incurs an E. coli MCL violation must conduct a
Level 2 assessment and take remedial action if any sanitary defects are
found. See section III.A.5 of this preamble for a full discussion of
conditions that trigger and define Level 1 and Level 2 assessments.
    The treatment technique requirements as proposed enhance public
health protection beyond the E. coli MCL for the following reasons:
     The assessment and corrective action provisions of the
treatment technique when the MCL for E. coli is exceeded require PWSs
to investigate the potential causes of the fecal contamination and
require timely remedial action if any sanitary defects

are found. Under the current TCR, there are no requirements for
investigation and corrective action after an MCL exceedance. Without
such a find-and-fix provision, the pathway for contamination may not be
identified and eliminated as sampling alone may not be adequate to
identify intermittent sources of fecal contamination. The assessment
and corrective action provisions of the proposed rule increase the
likelihood of finding and correcting any sanitary defect and reduce the
chance of recurrence of fecal contamination in the future.
     Using total coliforms in addition to E. coli as an
indicator to prompt assessment and corrective action increases the
sensitivity for identifying potential pathways for contamination. As
discussed in section II.D.2 of this preamble, the presence of total
coliforms indicates the potential existence of a pathway through which
fecal contamination could follow. 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. Analyses from EPA's 2005 Six-Year
Review 2 data (USEPA 2006b; USEPA 2010e) (see section VI.B of this
preamble for details on the Six-Year Review 2 data) and from the
proposed RTCR Economic Analysis (EA) occurrence modeling show that
total coliform presence in drinking water is approximately 20 to 40
times higher than E. coli occurrence in drinking water (see chapter 4
of the Proposed RTCR EA (USEPA 2010a)). Similarly, under the current
TCR, non-acute MCL (also referred to as monthly MCL) violations
(informed by total coliform occurrence) occur roughly 10 times more
often than acute MCL violations (informed by total coliform and E. coli
occurrence, essentially equivalent to the occurrence that triggers an
E. coli MCL violation under this proposed rule). Thus, including
monitoring of total coliforms, as well as E. coli, as part of a
treatment technique to indicate when systems must find and fix any
sanitary defects, substantially increases the likelihood of identifying
such defects.
     The proposed treatment technique was supported by the
advisory committee and is consistent with the recommendations in the
AIP. See AIP, pages 6-7.
    c. Request for comment. EPA requests comment on its proposal to
eliminate the MCLG and MCL provisions for total coliforms and fecal
coliforms and to include an MCLG and MCL for E. coli and coliform
treatment technique provisions based on monitoring for total coliforms
and E. coli. EPA also requests comment on its proposed definition of
the E. coli MCL.
3. Monitoring
    a. Provisions. As with the current TCR, the proposed 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.
Under the proposed 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.A.4 of this preamble. All samples taken for
proposed RTCR compliance (routine and repeat) may occur at a customer's
premises, dedicated sampling station, or other designated compliance
sampling location.
    Under the proposed RTCR, system sample siting plans must include
routine and repeat sample sites and any sampling points necessary to
meet the Ground Water Rule (GWR) requirements. The sample siting plan
is subject to State review and revision. The PWS may propose repeat
monitoring locations that are expected to be representative of a
pathway for contamination into the distribution system (for example,
near a storage tank). Instead of identifying set repeat sampling
locations (i.e., within five service connections upstream and
downstream of the original sampling location that tested total
coliform-positive), systems may elect to specify 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.
Upon State review, the PWS must demonstrate to the State's satisfaction
that the sample siting plan remains representative of the water quality
in the distribution system. The State may modify the SOP as needed. To
address access issues, small systems must specify in their sampling
plans where the two additional samples will be taken. 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.
    Under the proposed RTCR, PWSs may take more than the minimum
required number of routine samples and include the results in
calculating whether the total coliform treatment technique trigger for
conducting an assessment has been exceeded only if the samples are
taken in accordance with the sample siting plan and are representative
of water throughout the distribution system (see sections III.A.3 and
III.A.5 of this preamble).
    EPA is not proposing to make substantive changes to the current TCR
requirements for (1) special purpose samples, and (2) invalidation of
total coliform samples. EPA is proposing a minor modification to the
provision for special purpose samples by changing ``total coliform
MCL'' to ``coliform treatment technique trigger.''
    The following are the proposed monitoring requirements for
different categories of systems.
    i. Ground water NCWSs serving <= 1,000 people. (a). Routine
monitoring. The proposed RTCR requires ground water NCWS serving 1,000
or fewer people to routinely monitor each quarter for total coliforms
and E. coli. Seasonal systems under this category must routinely
monitor every month (seasonal systems are discussed later in this
section).
    (b). Transition to the RTCR. The proposed RTCR requires all ground
water NCWSs serving 1,000 or fewer people, including seasonal systems,
to continue with their TCR monitoring schedules as of the compliance
date of the RTCR, unless or until any of the conditions for increased
monitoring discussed later on in this section are triggered on or after
the compliance date or unless otherwise directed by the State,
including through the special monitoring evaluation conducted under a
sanitary survey. 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 (or an annual voluntary Level 2
assessment by a party approved by the State) and an annual site visit
each year thereafter to remain on annual monitoring.
    This rule proposes that after the compliance date of the final
RTCR, during each sanitary survey the State (which would be either EPA
or a State that has received primacy for this rule) 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 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 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 time periods.
    (c). 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 most recent sanitary survey shows the system is free
of sanitary defects, has a protected water source and meets approved
construction standards;
     The system must have a clean compliance history (no MCL
violations or monitoring violations under the current TCR and/or
proposed RTCR, no Level 1 or Level 2 trigger exceedances or treatment
technique violations under the proposed RTCR) for a minimum of 12
months. (For a more detailed discussion on Level 1 and Level 2
triggers, see section III.A.5 of this preamble); and
     An initial site visit by the State within the last 12
months to qualify for reduced annual monitoring, and recurring annually
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.
    (d). Increased monitoring. Ground water NCWS serving 1,000 or fewer
people on quarterly or annual monitoring that experience any of the
following events must begin monthly monitoring the month following the
event:
     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); or
     The system on quarterly monitoring has two monitoring
violations in a rolling 12-month period or system on annual monitoring
has one monitoring violation.
    The system must continue monthly monitoring until the requirements
in this section for returning to quarterly or annual monitoring are
met.
    (e). Requirements for returning to quarterly monitoring. To be
eligible to return 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 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.
    (f). Requirements for returning to reduced annual monitoring. To be
eligible to return to reduced annual monitoring after being placed on
increased 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;
--Continuous disinfection entering the distribution system and a
residual in the distribution system in accordance with criteria
specified by the State; and
--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 as approved by
the State.

    (g). Seasonal systems. The proposed rule requires all seasonal
systems to demonstrate completion of a State-approved start-up
procedure on and after the compliance date of the final RTCR. Seasonal
systems may continue with their TCR monitoring frequency after the
compliance date of the final RTCR unless or until any of the conditions
for increased monitoring discussed previously are triggered on or after
the compliance date or as directed by the State. Under the proposed
RTCR, seasonal systems are required to take routine samples monthly.
    To be eligible for reduced monitoring after the compliance date,
seasonal systems 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.A.3.a.i.(e) of this preamble, Requirements for returning to
quarterly monitoring.
     To be eligible for reduced annual monitoring, the system
must also meet all the reduced monitoring criteria discussed in section
III.A.3.a.i.(f) of this preamble, Requirements for returning to reduced
annual monitoring.
    (h). 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 current 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. In this proposal, consistent with the
current 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.
     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.
    ii. Ground water CWSs serving <= 1,000 people. (a). Routine
monitoring. The proposed RTCR requires ground water CWSs serving 1,000
or fewer people to routinely monitor each month for total coliforms and
E. coli.
    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
    (b). Transition to the RTCR. All ground water CWSs serving 1,000 or
fewer people continue with their current 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 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.
    (c). 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 for quarterly reduced monitoring, ground water CWSs
serving 1,000 or fewer people on monthly monitoring after the
compliance date must be in compliance with State-certified operator
provisions and meet each of the following criteria:
     The most recent sanitary survey shows the system is free
of sanitary defects (or has an approved plan and schedule to correct
them), has a protected water source, and meets approved construction
standards;
     The system must have a clean compliance history (no MCL
violations or monitoring violations under the current TCR and/or
proposed RTCR, no Level 1 or Level 2 trigger exceedances or treatment
technique violations under the proposed RTCR) for a minimum of 12
months; and
     The system must meet at least one of the following
criteria:

--An annual site visit by the State or a 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), or
--A cross connection control program, as approved by the State, or
--The system must maintain continuous disinfection entering the
distribution system and a residual in the distribution system in
accordance with criteria specified by the State, or
--The system must maintain 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); or
--Other equivalent enhancements to water systems as approved by the
State.
    (d). Return to routine monitoring requirements. When a system on
quarterly monitoring experiences any of the following events the system
must begin monthly monitoring:
     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); or
     System has two routine 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.
    (e). Additional routine monitoring. All systems 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). 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.
The current TCR additional routine monitoring requirements consist 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.
In this proposal, consistent with the current 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.
     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 the coliform treatment technique
requirements.
    iii. Subpart H systems of this part serving <= 1,000 people. The
monitoring requirements for subpart H systems of this part (PWSs
supplied by surface water source or ground water source under the
direct influence of surface water (GWUDI)) serving 1,000 or fewer
people remain the same as under the current rule (see Sec.  141.856).
These systems are not eligible for reduced monitoring. In addition, the
proposed 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.
    iv. PWSs serving > 1,000 people. The monitoring requirements for
PWSs serving more than 1,000 people remain the same as under the
current TCR (see Sec.  141.857), with the exception of the applicable
revisions to the repeat sampling locations provided in Sec.  141.858
and additional routine monitoring provisions. Systems on monthly
monitoring are not required to take additional routine samples the
month following a total coliform-positive sample. These systems are not
eligible for reduced monitoring. In addition, the proposed 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.
    b. EPA's rationale. i. Sampling sites and monitoring plans.
Consistent with current practice, the proposed RTCR requires systems to
develop a sample siting plan that is representative of the water
throughout the distribution system. EPA is proposing to maintain the
provision from the current TCR that indicates that sample siting plans
are subject to State review and revision. 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
including a periodic review. The advisory committee also recommended
that specific elements be included in the sampling plans such as the
routine and repeat sample sites and sampling locations necessary to
meet the requirements of the GWR. Alternative repeat monitoring
locations (e.g., at storage tanks and entry points to the distribution
system) are subject to State approval. The system must demonstrate to
the State's satisfaction that these alternative monitoring locations
are representative of the water quality in the distribution system.
    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.
In addition, EPA is proposing to require State approval if a ground
water system serving 1,000 or fewer people wants to use a single sample
to meet both the repeat monitoring requirements of the RTCR and the
source water monitoring requirements of the GWR (see section III.A.4 of
this preamble for further discussion of this topic).
    EPA is proposing to allow the use of dedicated sampling locations
for the following reasons:
     To reduce potential contamination of the taps. Utilities
will have more control to prevent contamination of the 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 houses.
     To improve sampling representation of the distribution
system. Allowing dedicated sample taps in areas where systems have not
been able to gain access will facilitate better sampling representation
of the distribution system.
    ii. Ground water PWSs serving <= 1,000 people. (a). Routine
monitoring. The advisory committee recommended that ground water NCWSs
serving 1,000 or fewer people remain under a routine quarterly
monitoring as provided in the current TCR. They believed that in
conjunction with the assessment and corrective action requirements,
public health protection would be maintained or improved without
increasing sampling costs over current TCR requirements. The advisory
committee also recognized that current sampling costs are not
insignificant for small systems, and wanted to recognize the good
performance of systems by allowing them to be able to continue to
qualify for reduced monitoring, but under the more specific and
rigorous criteria described previously. 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 monthly monitoring. This approach leverages the
limited resources of these small ground water NCWSs and of States, so
that systems with minimal problems can minimize their costs and States
can focus their resources on systems needing the greatest attention,
such as systems with problems or vulnerabilities.
    The advisory committee thought it best to continue with existing
routine monthly monitoring requirements for ground water CWSs serving
1,000 or fewer people in order to maintain the current levels of effort
to identify potential problems. Since sanitary surveys are required
under the GWR and these surveys provide substantial diagnostic value
and corrective action response for problems identified, specifying
higher routine monitoring frequency for these systems was not deemed
necessary. These systems may also qualify for reduced monitoring if
they meet certain criteria.
    (b). Transition to the RTCR. The advisory committee was concerned
about the ability of the States and systems to adopt the new
regulations and to make all the determinations that may be necessary to
determine the appropriate monitoring frequency within three years of
rule promulgation. Requiring significant changes in monitoring
frequencies in a short period (i.e., without a transition period) could
overwhelm State resources. The advisory committee recommended phasing
in the requirements and using the sanitary survey process to facilitate
a successful transition and implementation. The advisory committee,
therefore, recommended that these systems continue with their current
monitoring frequency during a transition period and that the State
review the monitoring frequency to determine whether it is appropriate
during each sanitary survey (USEPA 2008c, AIP p.9). This gives the
systems the opportunity to address operation

and maintenance issues to maintain existing monitoring frequency or
qualify for reduced monitoring. Systems on reduced TCR monitoring stay
on reduced monitoring during the transition period if they continue to
meet the reduced monitoring criteria. During the special monitoring
evaluation conducted as part of the periodic sanitary survey, the State
will determine whether the individual systems are on the proper
monitoring schedule.
    (c) Reduced monitoring. The reduced monitoring requirements are
intended to recognize that well-operated systems may be less vulnerable
to contamination. Therefore, certain conditions are specified under
which reduced monitoring could be allowed. These include a clean
compliance history for a minimum of 12 months, and an annual visit from
the State for systems taking one sample per year and correction of all
identified sanitary defects. Ground water NCWSs serving 1,000 or fewer
people, with a routine quarterly monitoring frequency, could qualify
for reduced annual monitoring, while ground water CWSs serving 1,000 or
fewer people, with a routine monthly monitoring frequency, could
qualify for reduced quarterly monitoring.
    For NCWSs on annual monitoring, the advisory committee believed
that requiring a system to have an annual site visit or a Level 2
assessment provides at least an equivalent level of diagnosis of
problems and vulnerabilities that might exist as compared to quarterly
monitoring without an annual site visit. Several States have elected to
conduct annual site visits while also doing annual monitoring for some
NCWSs.
    (d) Increased monitoring requirements for NCWSs. The advisory
committee wanted to recognize that if certain vulnerabilities are
identified in a system, the system should be required to conduct more
frequent monitoring to identify and correct its problems and better
protect public health. Other than sanitary surveys or other site
visits, monitoring is the primary means to identify pathways for
potential contamination. If the system is deemed more vulnerable to
such pathways, as indicated by the increased monitoring criteria, it
must conduct more monitoring.
    (e) Requirements for returning to routine monitoring and reduced
monitoring. The advisory committee believed that systems that address
or correct vulnerabilities as indicated by a clean compliance history
should be allowed to return to routine monitoring, and subsequently to
reduced monitoring (for NCWS). This provision allows for reduced
monitoring costs.
    (f) Seasonal systems. The advisory committee recognized that
seasonal systems have unique characteristics that make them more
susceptible to contamination. These systems do not maintain pressure
while not in operation, which can result in the intrusion of
contaminants. During the time when a seasonal system is not in
operation, septic tank drain fields or other pollution sources may
accumulate that could affect the conditions or quality of the source
water (especially for intermittent contaminants) that infrequent
monitoring may not be able to capture. If monitoring is done only at
the start-up, there may not be enough time for the system to reach
equilibrium (i.e., there might not be enough time to recognize if
microorganisms from a septic tank moved to the wellhead in seasonally
operated systems). Therefore, the proposed rule requires seasonal
systems to monitor routinely at a monthly frequency. Seasonal systems
can qualify for reduced monitoring if they meet certain criteria. For a
seasonal system to be allowed to monitor at a reduced frequency, the
proposed rule requires the system to have an approved sample siting
plan that designates the time period for monitoring and takes into
consideration site-specific conditions. A system on a reduced
monitoring schedule (less than monthly) must collect samples when there
is the greatest chance that contamination could be identified and, due
to the variability in water demands, when systems could be most
challenged.
    (g) Additional routine monitoring. EPA is proposing to retain the
requirement of taking additional routine samples the month following a
total coliform-positive sample for systems on quarterly or annual
monitoring. The advisory committee recognized both the benefits and the
limitations of additional routine monitoring. Additional routine
samples are meant to enhance the diagnostic ability and supplement the
infrequent routine monitoring of systems on quarterly or annual
monitoring. Without the provision of additional monitoring, systems on
annual or quarterly monitoring with a total coliform-positive sample
would not take any samples the following month. The advisory committee
believed that additional samples collected the following month are
appropriate to help recognize the problem if it still persists.
    For systems required to take the additional routine samples the
following month (i.e., systems on quarterly or annual monitoring), the
proposed RTCR changes the requirement from taking a total of five
routine samples to a requirement of just three routine samples. The
advisory committee recognized 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 recognizes that a reduction in the number of
samples taken could also mean a reduction in the number of positive
samples found. However, the reduction in the number of additional
routine samples in conjunction with the new assessment and corrective
action provisions of the proposed RTCR (discussed in section III.A.5 of
this preamble) leads to a rule that is ultimately more protective of
public health (i.e., more E. coli MCL violations being prevented) and
improvement in water quality (i.e., decrease in the total coliform and
E. coli-positive hit rates observed as shown by the Proposed RTCR EA
occurrence modeling results). See chapter 6 of the Proposed RTCR EA
(USEPA 2010a) for more details.
    For systems taking at least one sample monthly, the advisory
committee recommended no additional routine samples for these systems
for the following reason. Taking no additional routine samples the
following month substantially reduces monitoring costs. The assessment
and corrective action provisions will give systems the ability to
identify and prevent the occurrence of problems. EA modeling results
show that although there is a decrease in the number of E. coli MCL
violations found with the decrease in the number of additional routine
samples taken (i.e., going from five samples to one during the month
following a total coliform-positive), the assessment and corrective
action provisions lead to more E. coli MCL violations being prevented
compared to the current TCR (see Exhibit 6-7 of the Proposed RTCR EA
(USEPA 2010a) for more details).
    In addition, whenever a total coliform-positive occurs during
routine sampling, there is also a requirement to conduct repeat
sampling to determine the extent of contamination or if potential
pathways to contamination persist. For small systems serving 1,000 or
fewer people on monthly monitoring, if a repeat sample is total
coliform-positive, at least a Level 1 assessment will be triggered. If
a sanitary defect(s) is (are) found, the system is required to correct
the sanitary defect(s).
    For systems on monthly monitoring, the assessment and corrective
action provisions and the repeat sampling provisions mitigate the need
for

additional routine sampling for the following month.
    iii. Subpart H systems of this part serving <= 1,000 people. EPA is
not proposing to change the routine monitoring requirements for systems
using surface water or GWUDI serving 1,000 or fewer people, which
include not allowing reduced monitoring for these systems. Since
systems using surface water or ground water under the influence of
surface water tend to have much higher levels of contaminants in their
source water, and in general have more complex operations than ground
water systems, it is appropriate to allow reduced routine monitoring
for ground water systems but not for subpart H systems of this part.
The advisory committee recommended that no reduced routine monitoring
provisions be allowed for subpart H systems of this part serving 1,000
or fewer people.
    iv. Public water systems serving > 1,000 people. EPA is proposing
to eliminate the additional routine samples the month following a total
coliform-positive sample for PWSs serving between 1,000 and 4,100
people for the same reasons discussed previously for small ground water
systems monitoring monthly. PWSs serving more than 1,000 people are
currently required to routinely monitor monthly (one to four samples
per month depending on size) and continue to do so under the proposed
RTCR.
    c. Request for comment. EPA requests comment on the proposed
monitoring requirements for PWSs. Specifically, EPA requests comment on
the following questions: Are there other issues that EPA should
consider in its approach to help systems transition to the RTCR? Should
EPA develop guidance that would help States identify seasonal systems
and implement the RTCR requirements (e.g., suggestions for start up
procedures and identifying vulnerable time periods)? What start-up
procedures or other provisions regarding seasonal systems would be
appropriate for inclusion in such guidance? EPA also requests comment
on whether seasonal systems should be required to comply with State-
directed shut down procedures (in addition to start-up procedures).
    EPA requests comment on the following additional questions: Should
daily measurement of chlorine residual count toward the maximum
residual disinfectant level (MRDL) monitoring and be one of the
criteria for reduced monitoring? Should NTNCWSs be required to comply
with the CWS requirements (as they are in other rules such as DBP
rules) since NTNCWSs serve the same people over time and include
populations that may be at greater risk (e.g., schools, hospitals,
nursing homes)? Will the reduced, routine, and increased monitoring
requirements for NCWSs shift the fixed State resources from CWS
oversight to NCWS oversight in those States with large numbers of
NCWSs? If so, what might be done to limit the impact? Should EPA
develop guidance on how to develop a sample siting plan? Should sample
siting plans require State approval?
    EPA and the advisory committee did not identify any specific issues
regarding consecutive systems in the proposed RTCR. EPA requests
comment on whether there are such issues and how they should be
addressed in the RTCR.
4. Repeat Samples
    a. Provisions. Under the proposed RTCR, all systems must take at
least three repeat samples for each routine total coliform-positive
sample. This is a change from the current 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. EPA is not changing the following provisions: The 24-hour
limit within which the system must collect the repeat samples; the
authority of the State to extend this limit on a case-by-case basis;
and the non-waiver by the State of the requirement for a system to
collect repeat samples.
    In addition to taking repeat samples, systems must test each
routine total coliform-positive sample for E. coli. They must also test
any repeat total coliform-positive sample for E. coli. As with the
current TCR, 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 at the latest. The proposed rule is not changing the
provision that a 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.
    As with the current TCR, 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, 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. The system may
also propose alternative repeat monitoring locations in its sample
siting plan as discussed in this section.
    Under the proposed rule, ground water systems (GWSs) required to
conduct triggered source monitoring under the GWR must take ground
water source samples in addition to the repeat samples. 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 proposed RTCR and the source water
monitoring requirements of the GWR, but only if the State approves the
use of a single sample to meet both rule requirements (i.e., a dual
purpose sample) 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 proposed RTCR and must also comply
with the GWR requirements following a fecal indictor-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
proposed 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, then the system would have both an E. coli
MCL violation under the proposed RTCR and a second fecal indicator-
positive source sample under the GWR. The system would then need to
also comply with the treatment technique requirements under 40 CFR
141.403.
    Under the proposed rule, the system must collect all repeat samples
on the same day consistent with current TCR requirements. 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 ml.
    The proposed RTCR is not changing the requirement that systems
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 the
system determines that the coliform treatment technique trigger has
been exceeded and notifies the State. After a trigger (see section
III.A.5 of this preamble) 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.
    The proposed RTCR is also not changing the current TCR provision
that 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.
    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.A.5 of this
preamble for a discussion of the coliform treatment technique
triggers).
    b. EPA's rationale. i. Why EPA is maintaining a provision for
repeat sampling. As with the current TCR, the proposed RTCR requires
systems to take repeat samples after a total coliform-positive sample.
EPA believes that sampling immediately after an initial positive sample
(i.e., conducting repeat sampling) increases the likelihood of
identifying the source and/or nature of the possible contamination.
Analysis 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 Exhibit III-1). Repeat sampling (when total coliform-positive) can
indicate a current pathway for potential external contamination into
the distribution system.
    EPA used the Six-Year Review 2 (USEPA 2010e) data to support
statistical modeling which produced estimates of average occurrence of
routine total coliform-positive samples and repeat total coliform-
positive samples and to characterize how occurrence varies from system
to system. EPA's occurrence model assumes that, among similar systems,
the positive rate for total coliforms in routine samples varies as a
beta random variable. EPA used the Six-Year Review 2 data (USEPA 2010e)
to estimate the parameters for the distribution of occurrences of
routine and repeat total coliform-positive samples.
    Exhibit III-1 shows the relative probability of finding a total
coliform-positive result from routine samples versus from repeat
samples for 27 basic subsets of systems. The table combines regular
routine and additional routine samples since no distinction was
available for the Six-Year Review 2 data set (USEPA 2010e). The
relative probability is defined as the ratio of the probability of
getting a total coliform-positive result from a repeat sample to the
probability of getting a total coliform-positive result from a routine
sample.

  Exhibit III-1--Relative Probability of Total Coliform-Positive Samples in Routine Compared to Repeat Samples
----------------------------------------------------------------------------------------------------------------
                                                                  Average  pRTTC  Average  pRPTC   Ratio  pRPTC/
                         System type \1\                          \2\  (percent)  \3\  (percent)       pRTTC
----------------------------------------------------------------------------------------------------------------
TNCWS undisinfected GW:
    < 101.......................................................             4.8              28             5.9
    101-1,000...................................................             4.8              25             5.2
    1,001-4,100.................................................             2.5              17             6.9
NTNCWS undisinfected GW:
    < 101.......................................................             3.7              26             7.0
    101-1,000...................................................             2.7              26             9.6
    1,001-4,100.................................................             2.7              26             9.6
CWS undisinfected GW:
    < 101.......................................................             3.1              19             6.0
    101-1,000...................................................             2.7              19             7.1
    1,001-4,100.................................................             2.7              13             4.9
TNCWS disinfected GW:
    < 101.......................................................             2.3              14             6.2
    101-1,000...................................................             2.3              14             6.2
    1,001-4,100.................................................             2.3              14             6.2
NTNCWS disinfected GW:
    < 101.......................................................             1.6              11             6.7
    101-1,000...................................................             1.1              11             9.4
    1,001-4,100.................................................             1.1              11             9.4
CWS disinfected GW:
    < 101.......................................................             1.6             9.4             5.9
    101-1,000...................................................             1.2             9.4             7.6
    1,001-4,100.................................................            0.78             5.2             6.7
TNCWS SW:
    < 101.......................................................             2.3              14             6.2
    101-1,000...................................................             2.3              14             6.2
    1,001-4,100.................................................             2.3              14             6.2
NTNCWS SW:
    < 101.......................................................             1.6              11             6.7

    101-1,000...................................................             1.1              11             9.4
    1,001-4,100.................................................             1.1              11             9.4
CWS SW:
    < 101.......................................................             1.5             6.5             4.3
    101-1,000...................................................            0.95             6.5             6.8
    1,001-4,100.................................................            0.59             3.4             5.8
----------------------------------------------------------------------------------------------------------------
\1\ The following acronyms are used: (1) TNCWS Transient Non-Community Water System; (2) NTNCWS Non-Transient
  Non-Community Water System; (3) CWS Community Water System; (4) GW Ground Water; (5) SW Surface Water.
\2\ Average probability of a total coliform-positive from a routine total coliform sample.
\3\ Average probability of a total coliform-positive from a repeat total coliform sample.

    Exhibit III-1 shows that for any type and size of system,
regardless of source water and disinfection practice, repeat total
coliform samples (triggered by positive routine samples) are much more
likely to be positive than are routine samples. For small (serving 100
or fewer people) CWSs that provide undisinfected ground water, the
average repeat total coliform-positive rate (19 percent) is about six
times as great as the average routine total coliform-positive rate (3.1
percent) for these systems. The ratio of repeat to routine total
coliform-positive rates is greater for some sets of systems and smaller
for others, but a ratio of at least six to one is common. Similar
ratios of repeat to routine monitoring total coliform-positive rates
were found for disinfected systems (ground water and surface water
systems).
    Exhibit III-2 shows maximum likelihood distributions for the
positive rates in routine and repeat samples of small TNCWSs (serving
100 people or fewer) serving undisinfected ground water. The vertical
axis shows cumulative probability, which is the fraction of systems
having at most the corresponding horizontal axis value. Corresponding
to 0.5 on the vertical axis is the median probability of a total
coliform-positive. For example, for half of the systems, the
probability of getting a total coliform-positive is 1.3 percent (i.e.,
0.013 probability of total coliform-positive on horizontal axis) for
routine samples. This is the median probability of total coliform-
positive in routine samples. For repeat samples, the median probability
of a positive is 17.5 percent (i.e., 0.175 probability of total
coliform-positive on horizontal axis), which is about 13 times greater
than that of the routine samples.

[GRAPHIC] [TIFF OMITTED] TP14JY10.000

    ii. Frequency of repeat samples. The advisory committee recommended
that the current TCR requirement for systems serving more than 1,000
people to take three repeat samples subsequent to a routine total
coliform-positive be retained. The advisory committee recommended that
systems serving 1,000 or fewer people also be required to take three
repeat samples rather than the four required under the current TCR.
This view is supported by analysis of repeat sample records from the
Six-Year Review 2 data (USEPA 2010e).
    Repeat sampling helps utility operators to better understand the
extent and duration of potential pathways of contamination into the
distribution system. The Six-Year Review 2 data (USEPA 2010e) show that
the average percentage of samples that are positive among repeat
samples is much higher than that of routine samples, demonstrating that
when operators are required to take a second look at their systems
following the positive routine sample, they find, on average, a higher
rate of coliform presence than during routine sampling. In other words,
the high repeat total coliform-positive rate indicates the persistence
of total coliforms at such locations in the distribution system.
    Further analysis of the data shows that for all PWSs serving 1,000
or fewer people, two or more of the repeat samples are positive in 75
percent of those instances in which there are any positive repeat
samples, as shown in Exhibit III-3. For those 75 percent of instances,
reducing the number of repeat samples from four to three would have no
effect on the number of systems that would be triggered to conduct an
assessment of the system under the proposed RTCR. In these cases, at
least one of the remaining repeat samples would still be total
coliform-positive, and only one positive repeat sample is required to
trigger an assessment.
    The data show that one repeat sample is positive in 25 percent of
the instances in which any of the four repeat samples is positive. For
these instances, EPA estimates that if only three repeat samples had
been taken instead of four, three out of four (or 75 percent) of these
positive samples would still have been encountered.

   Exhibit III-3--Percentage of Instances With 1 or >1 Positive Repeat
  Samples Among Those Instances in Which >=1 Repeat Samples Is Positive
------------------------------------------------------------------------
                                             Number of positive repeat
                                                      samples
             System category             -------------------------------
                                                 1              > 1
------------------------------------------------------------------------
Undisinfected GWSs Serving <=1000.......             23%             77%
All PWSs Serving <=1000.................              25              75
------------------------------------------------------------------------
Note: Based on the analysis of Six-Year Review 2 dataset (USEPA 2010e)
  (described in chapter 4 of the Proposed RTCR EA (USEPA 2010a)). The
  total number of instances of positive repeat samples for undisinfected
  GWSs <=1000 is 2953, while all PWSs <=1000 have 3537 positive repeat
  samples.
Source: Proposed RTCR EA Appendix H (USEPA 2010a).

    When both of the two situations in which at least one repeat sample
is positive (either one positive repeat sample or more than one
positive repeat sample) are considered together, it is possible to
estimate the overall effect of reducing the number of repeats from four
to three, as presented in Exhibit III-4. The estimates in the table
indicate 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.

Exhibit III-4--Estimated Effects of Reducing Number of Required Repeat Samples for PWSs Serving <=1000 From 4 to
                                                        3
----------------------------------------------------------------------------------------------------------------
                                                                                Estimated
                                                                     Estimated                        overall
                                                   Percentage of   percentage of                   percentage of
                                                    events \1\      events that    Percentage of    events that
                                                  with exactly 1    would still     events \1\      would still
                                                  total coliform-  have 1 TC+ if    with >1 TC+    have >=1 TC+
                                                  positive (TC+)    1 out of 4     repeat sample   repeat sample
                                                   repeat sample  repeat samples                   if 1 out of 4
                                                                  were not taken                  repeat samples
                                                                                were not taken
----------------------------------------------------------------------------------------------------------------
                                                               A      B = A*0.75               C         D = B+C
----------------------------------------------------------------------------------------------------------------
Undisinfected GWSs Serving <=1000...............             23%             18%             77%           94.2%
All PWSs Serving <=1000.........................             25%             19%             75%           93.8%
----------------------------------------------------------------------------------------------------------------
\1\ Based on the analysis of the Six-Year Review 2 dataset (USEPA 2010e) (described in chapter 4 of the Proposed
  RTCR EA (USEPA 2010a)). The total number of events for undisinfected GWSs <=1000 is 2953, while all PWSs
  <=1000 have 3537 events.
Source: Proposed RTCR EA Appendix H (USEPA 2010a).

    Although dropping the required number of repeat samples from four
to three means that some fraction of triggers may be missed, the other
provisions of the proposed RTCR compensate for that change and, taken
as a whole, the provisions of the proposed 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 proposed RTCR are
triggered to conduct a Level 1 assessment. This permits an increase in
public health protection over the current TCR because PWSs are required
to assess their systems when monitoring results show that the PWS may
be vulnerable to contamination (indicated by exceeding the trigger).
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.
    It is important to point out that the majority of systems in this
category are ground water systems treating to less than 4-log
inactivation for viruses (see Exhibit 4.1 of the Proposed RTCR EA
(USEPA 2010a)). Because of the triggered source monitoring provision
under the GWR, these systems are required to collect a fecal indicator
sample from the source water following a total coliform-positive sample
in the distribution system in addition to the repeat samples. Under the
existing GWR and TCR, systems taking four repeat samples are permitted
to take the fourth repeat sample at the source water if they measure
for E. coli as the fecal indicator and if they have State approval.
Under the proposed RTCR, systems would continue to take this source
water sample to comply with the GWR in addition to the required repeat
samples in the distribution system to comply with the TCR. A positive
sample at the source that is not also considered a repeat sample would
not trigger an assessment under the proposed RTCR, but it would provide
diagnostic value to the system in addition to triggering additional
requirements under the GWR (i.e., corrective action or five additional
source water fecal indicator samples).
    As under the existing GWR and current TCR, with State approval,
ground water systems serving 1,000 or fewer people may use the sample
taken at the location required for triggered source monitoring to also
count toward the repeat monitoring requirements of the proposed RTCR.
In this case, the State must also approve the use of E. coli as the
fecal indicator under the GWR, and the system would comply with both
GWR and the proposed RTCR when a total coliform-positive or E. coli-
positive sample occurs. The advisory committee recommended this
flexibility to reduce the burden on small ground water systems that in
most cases will have a very limited distribution system and only one
source, consistent with the GWR.
    iii. Location of repeat samples. The advisory committee believed
that

requiring repeat samples to be taken within five service connections up
and downstream of the original total coliform-positive location can be
difficult for systems to implement within the required 24 hours for a
repeat sample because of issues such as access to the site. Therefore,
the advisory committee recommended that systems be allowed to develop
standard operating procedures (SOPs) as part of their sample siting
plan to identify alternative monitoring sites and facilitate the
identification of the source and extent of any problem. EPA is not
requiring prior State approval for this provision since there is no
reduction in monitoring and the SOP is expected to be used only by
larger systems with the technical resources to justify alternative
monitoring sites.
    The advisory committee also recommended that ground water systems
have the flexibility to propose repeat sampling locations that
differentiate potential source water and distribution system
contamination (e.g., by sampling at entry points to the distribution
system). See section III.A.3 of this preamble for additional discussion
on this topic. Consistent with its understanding of the intent of the
TCRDSAC, EPA has proposed that systems be allowed to exercise this
flexibility only with prior State approval. State approval is required
because this constitutes a reduction in monitoring (no separate
triggered source water samples). EPA believes that this reduction in
monitoring is appropriate only if the State determines that the dual
purpose sample provides public health protection equivalent to that
provided by separate repeat and source water samples. EPA believes that
many ground water systems serving 1,000 or fewer people, such as
systems with extensive distribution systems, will not be able to show
that this reduction in monitoring (i.e., a loss of repeat sample that
is near the total coliform-positive routine sample site, but not near
the source water sample site) will provide public health protection
equivalent to separate samples. EPA believes that systems with limited
or no distribution systems are the best candidate for approval.
    c. Request for comment. EPA requests comment on the foregoing
proposed repeat sampling requirements. Specifically, EPA requests
comment on the proposal to allow samples taken at the ground water
source to serve both as a triggered source sample under the GWR and as
one of the repeat samples under the proposed RTCR. EPA is also
requesting comment on whether systems should be allowed to use a dual
purpose sample simply by including that in the sample siting plan,
without prior State approval. Also, should systems using repeat
monitoring sites more than five connections upstream or downstream from
the routine total coliform-positive site be required to get prior State
approval?
5. Treatment Technique Requirements
    a. Provisions. i. Coliform treatment technique triggers. The non-
acute MCL violation for total coliforms under the current TCR is
effectively replaced by a coliform treatment technique involving
monitoring for total coliforms under the proposed RTCR. Under the
proposed treatment technique framework, the presence of total coliforms
is used as an indicator of a potential pathway of contamination into
the distribution system. As discussed in section III.A.2 of this
preamble, the proposed RTCR eliminates the associated MCLG and MCL for
total coliforms. The proposed revision specifies two levels of
treatment technique triggers, Level 1 and Level 2, and their
corresponding levels of response. Whether systems are required to
conduct either a Level 1 or Level 2 assessment is based on the degree
of potential pathway for contamination. The proposed rule further lays
out an additional trigger for a Level 1 assessment and defines Level 2
triggers that require a more in-depth examination of the system and its
monitoring and operational practices.
    The system has exceeded the trigger immediately once any of the
following conditions have been met:
    Level 1 treatment technique triggers:
     For systems taking 40 or more samples per month, the PWS
exceeds 5.0 percent total coliform-positive samples for the month; or
     For systems taking fewer than 40 samples per month, the
PWS has two or more total coliform-positive samples in the same month;
or
     The PWS fails to take every required repeat sample after
any single routine total coliform-positive sample.
    Level 2 treatment technique triggers:
     The PWS has an E. coli MCL violation (see section III.A.6
of this preamble for description of what constitutes an E. coli MCL
violation); or
     The PWS has a second Level 1 treatment technique trigger
within a rolling 12-month period, unless the first Level 1 treatment
technique trigger was based on exceeding the allowable number of total
coliform-positive samples, the State has determined a likely reason for
the total coliform-positive samples that caused the initial Level 1
treatment technique trigger, and the State establishes that the system
has fully corrected the problem.
     For PWSs with approved reduced annual monitoring, a Level
1 treatment technique trigger in two consecutive years.
    ii. Assessment. EPA is proposing an assessment process in the RTCR
to strengthen public health protection. Under the current TCR, a system
is not required to perform an assessment following a monthly/non-acute
MCL violation or an acute MCL violation. In contrast, the proposed RTCR
requires systems to conduct assessments following the triggers
specified above.
    EPA is proposing two levels of assessment based on the associated
treatment technique trigger: Level 1 assessment for a Level 1 treatment
technique trigger and Level 2 assessment for a Level 2 treatment
technique trigger. At a minimum, both Level 1 and 2 assessments must
include review and identification of the following elements:
     Inadequacies in sample sites, sampling protocol, and
sample processing,
     Atypical events that may affect distributed water quality
or indicate that distributed water quality was impaired,
     Changes in distribution system maintenance and operation
that may affect distributed water quality, including water storage,
     Source and treatment considerations that bear on
distributed water quality, where appropriate, and
     Existing water quality monitoring data.
    EPA expects that States will tailor specific assessment elements to
the size and type of the system and that each public water system in
turn will tailor its assessment activities based on the characteristics
of its distribution system.
    Level 1 assessment:
    A Level 1 assessment must be conducted when a PWS exceeds one or
more of the Level 1 treatment technique triggers specified above. Under
the proposed rule, this self-assessment shall consist of a basic
examination of the source water, treatment, distribution system and
relevant operational practices. The PWS might look at conditions that
could have occurred prior to and caused the total coliform-positive
sample. Example conditions include treatment process interruptions,
loss of pressure, maintenance and operation activities, recent
operational changes, etc. In addition, the PWS might check the
conditions of the following elements: sample sites, distribution
system, storage tanks, source water, etc.
    The PWS must complete the Level 1 assessment as soon as practical
after

notification of its monitoring results or failure to take repeat
samples. The PWS must submit the completed assessment form to the State
for review within 30 days after determination that the PWS has exceeded
the trigger. Failure to submit the completed assessment form within 30
days is a reporting violation. If the State determines that the
assessment is insufficient, the State will consult with the PWS. If
necessary after consultation, the PWS must submit a revised assessment
to the State on an agreed upon schedule not to exceed 30 days from the
date of the initial consultation.
    The completed assessment form must include assessments conducted,
all sanitary defects identified (or a statement that no sanitary
defects were identified), corrective actions completed, and a timetable
for any corrective actions not already completed. Upon completion and
submission of the assessment form by the PWS to the State, the State
shall determine if the system has identified the likely cause(s) for
the Level 1 treatment technique trigger and establish whether the
system has corrected the problem(s).
    Level 2 assessment:
    A Level 2 assessment must be conducted when a PWS exceeds one or
more of the Level 2 treatment technique triggers specified previously.
    A Level 2 assessment is a more comprehensive examination of the
system, its monitoring and operational practices than the Level 1
assessment. The level of effort and resources committed to undertaking
a Level 2 assessment will be commensurate with the more comprehensive
investigation and review of available information, and engage
additional parties and expertise relative to the Level 1 assessment
(see Appendix X of the AIP) (USEPA 2008c). Level 2 assessments must be
conducted by a party approved by the State: The State itself, a third
party, or the PWS where the system has staff or management with the
required certification or qualifications specified by the State. If the
PWS or a third party conducts the Level 2 assessment, the PWS or third
party must follow the State requirements for conducting the Level 2
assessment.
    The PWS must complete the Level 2 assessment as soon as practical
after notification that the PWS has exceeded a Level 2 treatment
technique trigger. The PWS must submit the completed assessment form to
the State for review within 30 days after determination that the PWS
has exceeded the trigger. Failure to submit the completed assessment
form after the PWS properly conducts the assessment is a reporting
violation. The State may direct expedited action or additional actions
such as in the case of an E. coli MCL violation. If the State
determines that the assessment is insufficient, the State will consult
with the PWS. If necessary after consultation, the PWS must submit a
revised assessment to the State on an agreed upon schedule not to
exceed 30 days from the date of the initial consultation.
    The completed assessment form must include assessments conducted,
all sanitary defects (or a statement that no sanitary defects were
identified), corrective actions completed, and a timetable for any
corrective actions not already completed. Upon completion and
submission of the assessment form by the PWS to the State, the State
shall determine if the system has identified the likely cause(s) for
the Level 2 treatment technique trigger and, if so, establish that the
system has corrected the problem(s).
    iii. Corrective action. The current TCR does not require systems
that have MCL violations to perform corrective actions. Under this
proposal, EPA is requiring PWSs to correct sanitary defects found
through either a Level 1 or Level 2 assessment. Ideally, systems will
be able to correct any sanitary defects found in the assessment within
30 days and report that correction on the assessment form. When the
correction of sanitary defects is not completed by the time the PWS
submits the completed assessment form to the State, the PWS must
complete the corrective action(s) on a schedule determined by the
State. This schedule may be developed in consultation with the PWS. The