Revised Total Coliform Rule

Rule 0400-45-01, Public Water Systems (Revised Total Coliform Rule) (June 5, 2016)

The Environmental Protection Agency finalized revisions to the 1989 Total Coliform Rule (TCR). The Revised Total Coliform Rule (RTCR) was published in the Federal Register on February 13, 2013. Tennessee is promulgating these rules to maintain primary enforcement authority (“primacy”) from EPA. Under the RTCR there is no longer a monthly maximum contaminant level (MCL) violation for multiple total coliform detections. Instead, the revisions require water 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 rulemaking also updates provisions in other rules of this chapter that reference analytical methods and other requirements in the 1989 TCR (e.g., Public Notification and Ground Water Rules).

The RTCR is the only microbial drinking water regulation that applies to all PWSs. Systems are required to meet a legal limit (i.e., maximum contaminant level (MCL)) for E. coli, as demonstrated by required monitoring. The RTCR specifies the frequency and timing of the microbial testing by water systems based on population served, system type, and source water type. The rule also requires public notification when there is a potential health threat as indicated by monitoring results, and when the system fails to identify and fix problems as required.

The RTCR establishes a health goal (maximum contaminant level goal, or MCLG) and an MCL for E. coli, a more specific indicator of fecal contamination and potential harmful pathogens than total coliforms. EPA replaces the MCLG and MCL for total coliforms with a treatment technique for coliforms that requires assessment and corrective action. Fecal coliform is no longer used in the RTCR. A public water system that exceeds a specified frequency of total coliform occurrence must conduct an assessment to determine if any sanitary defects exist; if any are found, the system must correct them. In addition, under the treatment technique requirements, a PWS that incurs an E. coli MCL violation must conduct a more detailed assessment and correct any sanitary defects found.

The RTCR also requires some new monitoring requirements for seasonal systems (such as campgrounds or water systems serving recreational areas), including a state-approved start-up procedure. The RTCR eliminates public notification requirements based only on the presence of total coliforms. Instead, the RTCR requires public notification when an E. coli MCL violation occurs, indicating a potential health threat, or when a public water system fails to conduct the required assessment and corrective action.

Water systems are required to develop written sampling plans by March 31, 2016. The rules are effective for public water systems on April 1, 2016. A water system may propose alternative repeat monitoring locations that are expected to better characterize or identify pathways of contamination into the distribution system. Systems may elect to specify either alternative fixed locations or criteria for selecting their repeat sampling locations on a situational basis in a standard operating procedure which is part of the sample siting plan.

Forms, Presentations and Guidance


Erich Webber

Drinking Water Technical Fellow