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TOTAL COLIFORM BACTERIA (including fecal coliform and E. coli)

Update: May 2004

Current Massachusetts Regulatory Limit
MMCL = no more than 5.0% samples total coliform-positive in a month. ORS has adopted the MCL published by the U.S. EPA. Refer to CMR 22.05 for additional regulatory information.

Federal Regulatory Limit
The MCL for total coliform is no more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform-positive per month.) Every sample must be analyzed for either fecal coliforms or E. coli if two consecutive total coliform positive samples are found. If one is also positive for E. coli fecal coliforms, the system has an acute MCL violation (U.S. EPA, 2002). The MCLG for Total Coliform Bacteria is zero.

Basis for Criteria
The MCL for total coliform was set as an indicator for the potential presence of sewage in the water supply.

Critical Effects
Total coliforms include fecal coliforms and Escherichia coli (E. coli). Fecal coliform bacteria are typically found in the intestines of animals and humans. E. coli is one type of fecal coliform bacteria. The presence of E. coli or other fecal coliform in water is an indicator that the water may be contaminated with human sewage or animal waste. While most indicator coliform bacteria are harmless, sewage may contain many disease-causing organisms (U.S. EPA, 2002).

Cancer Assessment: 

Biological Pathogen

Analytical Information
See CMR 22.20 

Analytical Methods:
See CMR 22.05

PQLs and analytical methods may have been updated since this guidance value was last revised. Updated analytical methods for drinking water and their associated PQLs may be found at

Federal Register. January 14, 2002. Environmental Protection Agency. Parts 9, 141 and 142. National Primary Drinking Water Regulations: Long Term 1 Enhanced Surface Water Treatment Rule. Final Rule. (67 FR 1811).

U.S. Environmental Protection Agency (U.S. EPA). July 2002. List of Contaminants and Their MCLs. EPA 816-F-02-013.