Total Coliform Rule

The 1989 Total Coliform Rule was developed to increase public health protection from pathogenic microbial contaminants. It requires all public water systems to monitor for the presence of total coliform bacteria in the distribution system.

Coliform bacteria is not pathogenic but is an indicator of pathogens that is relatively easy to detect.

In 2003 EPA announced the results of its first Six-Year Review of existing drinking water regulations, which at that time included 69 National Primary Drinking Water Regulations, including the TCR.

Based on that review, EPA decided to revise the TCR and used a negotiated rulemaking process to develop the appropriate revisions. In July 2007, EPA established the TCR Distribution System Advisory Committee to provide advice and make recommendations on revisions to the TCR. In September 2008, the DSAC recommended a number of changes to the TCR, which are reflected in an Agreement in Principle.

Based on that agreement, which AWWA helped formulate and signed, EPA proposed the Revised TCR in 2010.

Final RTCR published

On Feb. 13, 2013, the final Revised TCR was published in the Federal Register (PDF, 1.7MB). Significant improvements were made during the revision process, including new requirements that ensure assessment and corrective action when monitoring results indicate a potential risk of contamination exists.

The RTCR applies to all public water systems. Systems will have until April 2016 to comply with the rule requirements.

The revised rule eliminates the total coliform MCL and public notice based solely on total coliform occurrence. The revisions reflect the work of the EPA’s TCR/ Distribution System Advisory Committee, which included AWWA, consumer and environmental advocates and other stakeholders.

Core principles supported by AWWA and other committee members included: 

  • Providing appropriate public notification for true public health risks. 
  • Utilizing indicators with a proven track record, to do what they are best suited for. 
  • Improving utilization of state resources. 
  • Providing separate approaches addressing the unique characteristics of different types and sizes of systems. 

The final RTCR is very similar to the proposed RTCR.  In finalizing the RTCR, EPA:

  • Eliminates the total coliform MCL,
  • Requires assessments to identify sanitary defects when there are total coliform or E. coli exceedances.
  • Requires systems to fix sanitary defects identified through assessments.

This rule-making does not change the analytical methods used to comply with the TCR. Neither does it establish new requirements for finished water storage facility inspection and maintenance, cross connection control, water loss prevention, pressure management, distribution system management plans, or other distribution system operations.  Draft guidance for assessment and correction is anticipated in early 2013. These and other topics will be elements of assessments after exceedances making implementation of best practices a key element of complying with the RTCR.

Because, the RTCR applies to every public water system, this rule is central to every primacy agency program.  Water systems should be in routine communication with their primacy agency to stay abreast of state-specific implementation activities

regulatory details and resources

Research and information collection

Research and Information Collection Partnership

The DSAC also recognized that a number of issues have the potential to affect distribution system water quality but that additional information and research was needed prior to any additional regulatory actions.

EPA and the Water Research Foundation collaborated to form the Distribution System Research and Information Collection Partnership. In May 2010, the DSRCIP prepared a summary of research priorities. Some of this distribution system research is underway.

Backflow prevention and cross-connection control

Currently, the SDWA does not mandate federal requirements for cross-connection control or backflow prevention. Engineering practices, local ordinances and state regulations address local cross-connection control programs that plumbers and water systems operate.

EPA has developed a best practices guide on cross-connections and AWWA has established an online Resource Community on this topic that provides extensive information and assistance on both topics. 

Optimization partnerships

The DSAC also recognized and advocated for optimization partnerships, particularly those focused on protecting the integrity of drinking water quality once it is delivered to the distribution system. In the RTCR Agreement in Principle, the committee emphasized the purpose of such partnerships should be to inform and inspire proactive systems to implement best management practices that emphasize protection of public health.

Currently there are two such programs currently in operation:

Partnership For Safe Water Distribution System Optimization Program

The PSW Distribution System Optimization Program is patterned after the Partnership's Water Treatment Program. The Partnership partially funded a project conducted by the Water Research Foundation to develop criteria for optimization of water distribution system operation.

Area-Wide Optimization Program

The AWOP is a operated by individual states with support from EPA regions. The focus of AWOP implementation is capacity development and, like the PSW, it was initially focused on conventional treatment plant performance, principally achieving Interim Enhanced Surface Water Treatment Rule turbidity goals.

The program continues to expand into other aspects of water system operations, and some states and regions support a distribution system component. Information is available through state program contacts.

Premise plumbing

In 2005 a National Academy of Sciences panel on Public Water Supply Distribution Systems: Assessing and Reducing Risks released a report noting that  premise plumbing is a portion of the tap water delivery system that is subject to almost every problem that water system operators manage in the distribution system.

Homeowners, commercial property managers and maintenance staff at large institutions are seldom aware of the potential for water quality issues or familiar with the tools and practices to resolve such issues when they occur. The NAS panel reasoned that premise plumbing was not only a potential health hazard worth of national focus but that it was also a very valuable asset citing a national replacement value of more than $1 trillion.



EPA is developing guidance on treatment options for Legionella and has released a relevant literature review

AWWA is developing a communications guide to help water systems talk with building owners and operators about Legionella.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers is in the final stages of preparing a standard, ASHRAE SPC 188P Prevention of Legionellosis Associated with Building Water Systems.

When finalized, it will be an ANSI-recognized standard. Moreover, the primary audience for the standard is building owner/operators (e.g., commercial buildings, hospitals, schools, etc.). This standard is unique in that Legionella pneumophila is a contaminant on EPA's third Contaminant Candidate List. Also, the standard goes to risk management associated with potable water use in premise water systems. Information on the standard is available at the ASHRAE website.