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Bathing Beach Monitoring

Beaches Environmental Assessment and Coastal Health Act of 2000. As of April 2004, each state having coastal recreation waters is required to adopt water quality criteria and standards for coastal recreational waters for those pathogens and pathogen indicators that could be harmful to humans.

Beach monitoring in Michigan

Pursuant to this law, the Michigan Water Research Center is offering water analyses to determine if water is safe and healthy for people who visit our public and private beaches. Since contamination of water can cause gastrointestinal or respiratory illness, it is important to monitor the water quality at our beaches.

Beach water samples are analyzed for Escherichia coli ( E. coli). E. coli is an indicator that water has been contaminated by sewage, waste or other waste water that may contain harmful bacteria. Health departments conduct bathing beach monitoring programs to help protect public health.

The standard method used for analyzing water samples can be found in the document entitled “Improved Enumeration Methods for the Recreational Water Quality Indicators: Enterococci and Escherichia coli.” (EPA  821/R097/004) Results of the assays are available after approximately 28 hours. A minimum of three samples should be taken each time a beach area is monitored. The daily geometric mean calculated from these samples must be below 300 E. coli per 100 milliliters for water to be considered safe for swimming.

Sample collection


It is best to collect beach samples by wading into the water to a depth that allows collection in 3 to 6 feet of water. Collect samples about 1 foot below the surface, and be careful not to stir up the sediment.

Using sterile bottles, three 100-mL samples should be collected at each beach site. Sterile bottles are available from the MWRC.

Collection time

Samples should be taken early in the day as to assure enough time to process them in the laboratory.

Storing samples

Store samples in a cooler on ice until they are returned to the MWRC, where they will be assayed for E. coli

Additional information

More information is available by contacting the Michigan Water Research Center.

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