The Revised Total Coliform Rule

Hydrogeology, Geology, & Environmental Issues / Field Methods & Procedures

Date posted: 01/18/16

Michael J. Schnieders reports that although initial legislation took place much earlier, the total coliform rule (TCR) of 2001 created quite a bit of stress for the groundwater industry. The TCR contained a significant expansion of microbial testing of wells and public water supplies. Beginning April 1, 2016, and earlier in some states, revisions to the TCR begin to take effect. Are you and your customers prepared? The new revisions reflect a better understanding of coliform occurrence as well as the total coliform and fecal coliform tests. Although often misunderstood in the past, the new revisions and supporting documentation reflect the use of the total coliform test as an indication of potential problems. In my opinion, these changes parallel what we in the groundwater industry have encountered since the TCR became law. Research in our lab has shown many of the problems with coliform-impacted wells stemmed from inactivity and a lack of maintenance, not contamination. As part of the revisions, the U.S.EPA eliminated the maximum contaminant level (MCL) for total coliforms and has established a new maximum contaminant level goal (MCLG) and MCL for E. coli. Additionally, the requirements for testing of total coliforms and E. coli are now part of a specific sample plan unique to the public water system. This is an important change as each well is unique and plays a different role in each public water supply. The revision also expands sampling requirements for smaller, seasonal use systems. In addition to monitoring requirements, the revision calls for the development of start-up procedures to address the impacts of idle wells and limit potential exposure. Again, this coincides with the vulnerabilities that the industry have witnessed with idle and inactive wells. As revisions to the total coliform rule begin to take effect this year, many communities are not aware of or have failed to understand vulnerabilities surrounding their well systems.