Microbial (Pathogen)/Recreational Water Quality Criteria

EPA develops criteria to protect people from microbial organisms (sometimes referred to as pathogens) such as bacteria and viruses in water bodies (e.g., lakes, rivers, beaches).  Pathogens can make our waters unsafe for humans. Swimming and other recreational activities in water contaminated with pathogens can make people ill. People can also become exposed by drinking untreated water from contaminated water bodies.

EPA recommends criteria for limiting microbial organisms in water bodies to protect human health. State and tribal governments can use the criteria as guidance when setting their own water quality standards to protect human health.

On this page:

Recreational Water Quality Criteria

Review of Coliphages as Possible Indicators of Fecal Contamination for Ambient Water Quality

This is a literature review of the scientific information that EPA will evaluate to develop coliphage-based ambient water quality criteria for the protection of swimmers.  It generally indicates that coliphages are equally good indicators of fecal contamination as EPA’s currently recommended criteria for E. coli and enterococci. In addition, coliphages are better indicators of viruses in treated wastewater than bacteria. While EPA conducts its evaluation of coliphages as possible viral indicators for water quality, we continue to recommend that states adopt our 2012 recreational water quality criteria into their water quality standards. 

Drinking Water Regulatory Support Documents for Microbials

Criteria documents and guidance for drinking water contaminants provide information so preliminary decisions can be made as to whether the contaminant is a significant health threat via drinking water exposure and whether sufficient data exists to perform quantitative risk assessments.

Criteria documents and guidance for surface waters on this page provide information to help states adopt water quality standards that protect the health of people who recreate in water.

Water Quality Standards and Implementation

Drinking Water Health Documents

Health Advisories serve as informal technical guidance to assist federal, state, and local officials responsible for protecting public health when emergency spills or contamination situations occur. They are not to be construed as legally enforceable federal standards. The Health Advisories are subject to change as new information becomes available.

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