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Water: Total Coliform Rule

Total Coliform Rule Revisions


EPA published the Revised Total Coliform Rule (RTCR) in the Federal Register (FR) on February 13, 2013 (78 FR 10269). It is the revision to the 1989 Total Coliform Rule (TCR).

Why revise the 1989 TCR?

The 1996 amendments to the Safe Drinking Water Act [Section 1412(b) (9)] require the Administrator to review and revise, as appropriate, each national primary drinking water regulation not less often that every six years. EPA published its decision to revise the TCR in July 2003 as part of its National Primary Drinking Water Regulation (NPDWR) review.


  • Upholds the purpose of the 1989 TCR to protect public health by ensuring the integrity of the drinking water distribution system and monitoring for the presence of microbial contamination.
  • Requires public water systems (PWSs) to meet a legal limit for E. coli, as demonstrated by required monitoring.
  • Specifies the frequency and timing of required microbial testing based on population served, public water system type and source water type: ground water or surface water.

When must PWSs comply with the RTCR requirements?
Unless a State determines an earlier effective date, all PWSs must comply with the RTCR requirements starting April 1, 2016. All PWSs include:

  • Community Water Systems (CWSs),
  • Non-Transient Non-Community Water Systems (NTNCWSs), and
  • Transient Non-Community Water Systems (TNCWSs).

What are the key provisions PWSs must comply with under the RTCR?

Provision Category
Key Provisions
Contaminant Level
  • Addresses the presence of total coliforms and E. coli in drinking water.
  • For E. coli (EC), the Maximum Contaminant Level Goal (MCLG) is set at zero and the Maximum Contaminant Level (MCL) is based on the occurrence of a condition that includes routine and repeat samples. 
  • For total coliforms (TC), PWSs must conduct a Level 1 or Level 2 assessment of their system when they exceed a specified frequency of total coliform occurrence. Other events such as an MCL violation or failure to take repeat samples following a routine total coliform-positive sample will also trigger an assessment. Any sanitary defects identified during an assessment must be corrected by the PWS. These are the treatment technique requirements of the RTCR.
  • Develop and follow a sample siting plan that designates the PWS's collection schedule and location of routine and repeat water samples.
  • Collect routine water samples on a regular basis (monthly, quarterly, annually) and have them tested for the presence of total coliforms by a state certified laboratory.
  • Analyze all routine or repeat samples that are total coliform positive (TC+) for E. coli.
  • Collect repeat samples (at least 3) for each TC+ positive routine sample.
  • For PWSs on quarterly or annual routine sampling, collect additional routine samples (at least 3) in the month after a TC+ routine or repeat sample.
  • Seasonal systems must monitor and certify the completion of a state-approved start-up procedures
Level 1 and Level 2 Assessments and Corrective Actions
  • PWSs are required to conduct a Level 1 or Level 2 assessment if certain conditions indicate that they might be vulnerable to contamination, and fix any sanitary defects within a required timeframe.
Reporting and Recordkeeping
  • PWSs are required to report certain items to their states. These reporting and recordkeeping requirements are essentially the same as under TCR with the addition of Level 1 and Level 2 requirements.
Violations, Public Notification (PN) and Consumer Confidence Report (CCR)
  • PWSs incur violations if they do not comply with the requirements of the RTCR. The violation types are essentially the same as under the TCR with few changes. The biggest change is no acute or monthly MCL violation for total coliform positive samples only.
  • PN is required for violations incurred. Within required timeframes, the PWS must use the required health effects language and notify the public if they did not comply with certain requirements of the RTCR. The type of PN depends on the severity of the violation.
  • Community water systems (CWSs) must use specific language in their CCRs when they must conduct an assessment or if they incur an E. coli MCL violation.

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Minor Corrections to the Revised Total Coliform Rule (RTCR)

Minor corrections to the final RTCR became effective on April 28, 2014. No comments were received on the Direct Final Rule published on February 26, 2014 and the corrections therefore became effective without further notice. See the Direct Final Rule Federal Register Notice.

Revised Total Coliform Rule (RTCR) – Final Rule

On February 13, 2013, EPA published in the Federal Register the revisions to the 1989 TCR.  EPA anticipates greater public health protection under the Revised Total Coliform Rule (RTCR) requirements.  The RTCR:

  • Requires public water systems that are vulnerable to microbial contamination to identify and fix problems; and
  • Establishes criteria for systems to qualify for and stay on reduced monitoring, which could reduce water system burden and provide incentives for better system operation.

For more information on requirements, please review RTCR Webinar - April 10, 2013 (PDF) (59 pp, 496K).

Public water systems (PWSs) and primacy agencies must comply with the revised requirements by April, 2016.  Until then, PWSs and primacy agencies must continue complying with the 1989 TCR.

RTCR Federal Register Notice and Supporting Documents

RTCR Implementation Materials

  • new The Revised Total Coliform Rule (RTCR) State Implementation Guidance Document-Interim Final (PDF) (295 pp, 2MB) EPA 816-R-14-004, December 2014
    This document provides guidance to states, tribes and the U.S. Environmental Protection Agency exercising primary enforcement responsibility under the Safe Drinking Water Act (SDWA) and contains EPA’s current policy recommendations for complying with the RTCR.

  • Revised Total Coliform Rule: A Quick Reference Guide (PDF) (3 pp, 450K)
    EPA 815-B-13- 001, September 2013
    The RTCR establishes a maximum contaminant level (MCL) for E. coli and uses E. coli and total coliforms to initiate a “find and fix” approach to addr ess fecal contamination that could enter into the distribution system. It requires public water systems (PWSs) to perform assessments to identify sanitary defects and subsequently take action to correct them.

Assessments and Corrective Actions- Interim Final

Revised Total Coliform Rule Assessments and Corrective Actions Guidance Manual, Interim Final (164 pp, 2MB) EPA 815-R-14-006, September 2014
Target audience: Public water systems, States, Primacy agencies.
Status: Interim Final
Description: The guidance manual provides public water systems and primacy agencies with guidance on complying with and implementing the assessment and corrective action requirements of the  Revised Total Coliform Rule (RTCR). Under the RTCR, public water systems that are vulnerable to microbial contamination in the distribution system (as indicated by their monitoring results for total coliforms and E. coli) are required 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. The guidance manual provides information on how to conduct assessments to identify the causes of total coliform and E. coli occurrence in the distribution system, and on the corresponding corrective actions that systems can take to correct the problem.

Rule Making History

Total Coliform Rule Distribution System Advisory Committee

EPA established the Total Coliform Rule Distribution System Advisory Committee (TCRDSAC) under the Federal Advisory Committee Act to provide advice and make recommendations to the Agency on revisions to the 1989 TCR. For more information about the Federal Advisory Committee that recommended changes to the 1989 TCR please review our TCRDSAC page.

Proposed Revised Total Coliform Rule

In July 14, 2010, EPA proposed revisions to the 1989 TCR that are consistent with the recommendations of the TCRDSAC. The proposed rule was open for public comment for 90 days.

Federal Register Notice

Supporting Document

Request for Review by the Science Advisory Board Drinking Water Committee on EPA's Draft Supporting Analyses for the Proposed Revised Total Coliform Rule

The Environmental Protection Agency (EPA), Office of Water, is requested that the Science Advisory Board (SAB) Drinking Water Committee (DWC) review the draft supporting analyses for the proposed Revised Total Coliform Rule (RTCR). The SAB review focused on (1) the data sources used to estimate baseline total coliform and E. coli occurrence, public water system profile, and sensitive subpopulations in the United States, (2) the occurrence analysis used to inform the benefits analysis, (3) the qualitative analysis used to assess the reduction in risk due to implementation of the rule requirements, and (4) analysis of the engineering costs and costs to states resulting from implementation of the revisions. A copy of the report that contains the SAB's findings and recommendations is available per Docket ID number EPA-HQ-OW-2008-0876 in the following link:

The following files are provided to facilitate the SAB DWC review:

Draft Supporting Analyses

Supplemental Information

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Past meetings and webcasts

This section contains information on past meetings and webcasts that EPA conducted to support the revision process of the 1989 TCR.

  • Total Coliform Rule Distribution System Advisory Committee (TCRDSAC) Meetings
    The Total Coliform Rule Distribution System Advisory Committee met 13 times to deliberate on the revisions to the TCR.  For information on these meetings and on the TCRDSAC, please review ourTCRDSAC page.
  • Total Coliform Rule / Distribution System Stakeholder Technical Workshop and Request for Nominations – January 2007
    EPA held a technical workshop in Washington, DC, to discuss available information on the 1989 TCR and available information regarding risks in distribution systems. As part of the technical workshop, EPA discussed information and analytic approaches for characterizing risks posed by the distribution system. Subsequently, the Agency established the Total Coliform Rule Distribution System Advisory Committee under the Federal Advisory Committee Act to provide advice and recommendations on potential revisions to the 1989 TCR and to address public health risks from contamination of distribution systems. See the links to the agenda and presentations below for more information on the topics covered.
  • Agenda (PDF) (15 pp, 40K)

TCR Issue Papers

EPA and AWWA developed a series of TCR Issue Papers to present available information on a range of issues related to the TCR. The paper topics were based on feedback from stakeholders and comments received on the TCR since promulgation. The objective of the issue papers is to review the available data, information and research regarding issues relevant to the revision of the TCR, and where relevant, identify areas in which additional research may be warranted. Draft papers were completed in June 2006 and were reviewed by a range of industry experts and stakeholders from :

  • EPA's Office of Ground Water and Drinking Water (OGWDW);
  • academia;
  • water utilities;
  • Association of Metropolitan Water Agencies (AMWA);
  • American Water Works Association (AWWA);
  • American Water Works Service Company (AWWSC);
  • National Rural Water Association (NRWA);
  • environmental consulting companies;
  • and state regulators.

EPA held a TCR Experts workshop in June 2006 to discuss the draft papers and possible rule revisions. The review and comment by the experts constitutes peer review of the papers.

EPA will use the papers as information sources for discussions of TCR issues with the drinking water community, experts and stakeholders. The papers are:

Note - The papers present available information and do not represent Agency policy or necessarily reflect the views of EPA. The papers on Distribution System Monitoring Strategies and Distribution System Inventory were prepared by AWWA.

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Recommendations from Stage 2 M/DBP Agreement in Principle on Distribution Systems

In 2000, as part of its recommendations concerning the Long-Term 2 Enhanced Surface Water Treatment Rule and the Stage 2 Disinfection Byproducts Rule, the Stage 2 Microbial/Disinfection Byproducts (M/DBP) Federal Advisory Committee recognized the following points in its Agreement in Principle

"Finished water storage and distribution systems may have an impact on water quality and may pose risks to public health." "Cross-connections and backflow in distribution systems represent a significant public health risk." "Water quality problems can be related to infrastructure problems and that aging of distribution systems may increase risks of infrastructure problems." "Distribution systems are highly complex and that there is a significant need for additional information and analysis on the nature and magnitude of risk associated with them."

The FACA concluded that EPA should review and evaluate available data and research on those aspects of distribution systems that may create or pose risks to public health as a part of the Six-Year Review of the TCR. The FACA also concluded that EPA should initiate a process with stakeholder participation for addressing requirements for cross-connection control and backflow prevention, and distribution systems issues related to significant health risks.

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