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Water Sampling Requirements

Man testing for PFAS in lab
Environment, Great Lakes, and Energy

Water Sampling Requirements

Although groundwater is typically a safe source of drinking water and actual events of drinking water contamination are rare, contaminants can enter the drinking water supply if any of the protective barriers are breeched. Heightened public awareness, concern for public health, and advancements of technology are factors behind legislative action to set national standards regarding the levels of contaminants in drinking water.

Water quality monitoring has an important role in identifying breeches in the system that may threaten safe and aesthetically pleasing water, however, it is important to understand that a water sample is a very small part of the total water supply and not a protective barrier.

There are potentially thousands of different contaminants that could find their way into drinking water systems that may be harmful to health. It is impractical to attempt to test for all possible contaminants. Priorities for testing are determined, in general, based on national occurrence data, health effects and technology.

Sampling requirements are tied to population served, source of water, and  sampling history results of the sanitary survey.

Required monitoring

  • Systems that serve 1,000 or fewer persons per day must sample quarterly unless on a different frequency as prescribed by the local health department.

    Systems that serve 1,001 or more persons per day must sample monthly. The number of samples per month is determined by the population served.

  • Annual sampling required for all systems unless results indicate a heightened level and increased monitoring in prescribed by the local health department. 

  • Each system is evaluated and put on a monitoring cycle prescribed by the local health department.

Lab benchtop with test tubes on it.
Lab benchtop with test tubes on it.

Curious about drinking water labs?

The Remediation and Redevelopment Division (RRD) of EGLE certifies laboratories to ensure that proper methods and quality control are used in the testing of drinking water samples.