Laboratory Testing

The Environmental Health Unit maintains its own water bacteria testing laboratory for public and private water supplies. The laboratory is New York State and Environmental Protection Agency (EPA) approved and certified to test potable (drinking) water and non-potable (lakes, ponds, streams) water for total coliform and E.coli.

Routine Testing

The Health Department routinely tests all community (cities, villages, mobile home parks) and non-community (restaurants, hotels) water supplies to ensure that total coliform and E.coli levels are absent.

Private Water System Testing

The Environmental Health Unit also tests private water systems (homes and businesses) primarily when the properties are being sold or when a private homeowner requests a bacteria test be performed.

Public Water Testing

The Environmental Health Unit routinely tests public bathing beach water, lakes, pond and streams for a safe level of the total coliform and E. coli bacteria.

Test Results

Water test results will be available within 48 hours of sample submission.

What are Coliform Bacteria?

Coliform bacteria are a group of bacteria that live in the digestive tract of all warm blooded animals (birds, cats, dogs, humans, etc.) and are used as indicator bacteria. Most coliform do not usually make people ill, since the bacteria naturally live in humans. However, the presence these bacteria in water indicates that the water may have been in contact with fecal matter and the many viruses and bacteria that can cause illness.


  • $20 per sample includes a sample bottle and test results; sample collected by an individual and brought to Mayville
  • $40 per sample; sample collected and submitted by a representative of the Environmental Health Unit

View the water sampling procedure (PDF).