Revised Total Coliform Rule (RTCR)
On April 1, 2016, the Revised Total Coliform Rule (RTCR) will replace the Total Coliform Rule. The RTCR will better protect water users against waterborne illness by requiring water systems to do an assessment to “find” and then “fix” any sanitary defects that could provide a pathway for microbial contaminants to enter the distribution system. The RTCR requires systems to monitor for the presence of total coliforms and E. coli in drinking water. Total coliforms are a group of related bacteria that are (with few exceptions) not harmful to humans. A variety of bacteria, parasites, and viruses, known as pathogens, can potentially cause health problems if humans ingest them. EPA considers total coliforms a useful indicator of other pathogens for drinking water. Total coliforms are used to determine the adequacy of water treatment and the integrity of the distribution system.
The most notable changes are that the Revised Total Coliform Rule establishes a maximum contaminant level (MCL) for E. coli and adopts a “find and fix” approach to address potential pathways of contamination that could result in bacteriological contamination in the water system. It requires PWSs to perform assessments to identify sanitary defects in the water system and to take action to correct any defects that are found.
Other notable changes are:
- Reducing the distribution samples for all systems serving 1000 persons or less to 1 distribution per month or quarter.
- All nontransient noncommunity water systems will go from monthly to quarterly monitoring.
- Reducing the number of repeat samples from four to three for all systems
- Changing the requirement for additional routine samples the month after a total coliform positive sample is collected
- For PWSs that monitor monthly, no additional samples will be required for the month following a total coliform positive sample
- For PWSs that monitor quarterly, the number of additional samples the month following a total coliform positive sample will be reduced from five to three samples
- Monitoring will be increased from quarterly to monthly for non-community and non-transient non-community PWSs after exceeding the E. coli MCL, when multiple assessments have been triggered, or after other certain violations.
- There is no total coliform maximum contaminant level, instead water systems will be conducting Level 1 or Level 2 assessments. This means there is no public notice for multiple total coliform positive samples.
The Revised Total Coliform Rule works in conjunction with the existing Ground Water Rule. Therefore, the coliform monitoring revisions under the RTCR do not change the triggered monitoring at groundwater sources required by the Ground Water Rule for all water systems serving groundwater.
Guide for Small Public Waters Systems (Environmental Protection Agency)