Come next year, the Revised Total Coliform Rule (RTCR) is set to bring major changes to water distribution systems and the original 1989 EPA regulation, which established health goals and legal limits on total coliform (TC) levels in drinking water

The revised rule "will result in better management and operation of water systems," says Gary Lynch, vice president of water quality at Park Water Co.

The EPA requires that each National Primary Drinking Water Regulation be evaluated and changed as necessary at least every six years. In July 2003, a TCR review was deemed appropriate, designating this year as the revisionary period. The Microbial/Disinfection By-Products (M/DBP) Federal Advisory Committee recommended several modifications to the current regulation, created in 1992 and one of only two that affect all 160,000 water systems in the country. The new revised rule, based on the committee's recommendations, may be found in the Agreement in Principle (AIP).

The rule will remove TC and fecal coliform from their standing as regulated contaminants with Maximum Contaminant Level Goals (MCLGs) and Maximum Contaminant Levels (MCL). The former will be used as an indicator, while fecal coliform provisions will be removed altogether. E. coli will then become the sole regulated contaminant with an MCLG of zero.

Should TC be detected, it will trigger additional monitoring and assessments to locate the source and cause, whether it be due to cross-connection, leak, or other defects in the sanitation or distribution system coliform monitoring process. The committee also recommends provisions for public notification and corrective action should rule violations occur.

Scheduling for the revised TCR public information can be found in the Spring 2009 Regulatory Agenda (p. 143,). The Notice of Proposed Rule Making is set to occur August 2010, followed by final action in October 2012. Lynch suggests that water systems utilize the AIP as a resource and for guidance on how to prepare for the upcoming changes. Water systems should not, however, alter their monitoring practices until authorized to do so.

Additional information on the rule revisions is posted on the EPA Web site.