Bacteria in Water: E. coli and Legionella Testing in Vermont

The Vermont Department of Health Laboratory tests different types of environmental water samples for bacteria like E.coli or Legionella.

E. coli in recreational (swimming) waters

Water samples from ponds, lakes and rivers are tested for Escherichia coli, commonly known as E. coli, to determine whether it is suitable for swimming. E. coli is a bacterium that comes from human or animal waste. The Vermont Department of Health Laboratory (VDHL) performs a test to “quantitate” or count the numbers of E. coli in a water sample to determine its suitability for swimming. Recreational water should have less than 235 E. coli organisms per 100 ml of water to be considered suitable for swimming. 

  • Municipal or non-profit managed public swimming areas should be monitored regularly according to the Vermont Department of Health’s Healthy Recreational Waters Guidelines.
  • Individuals may use this test to determine the safety of swimming areas on their property, or their lake frontage.

The VDHL has the following test types available:

  • Kit SW:  Provides Counts of E. coli in recreational water up to 2000 MPN/100 ml.
  • More information on Kit SW.
  • To request a kit by mail, view/print out our order form and send in with form of payment.
  • Kits can also be purchased in person or over the phone; visit our Contact Us and Directions page for more information.

For more information from the Department of Health on healthy recreational water.

You can view the current test results from the Vermont State Parks Swimming Information Page.

E. coli in agricultural or irrigation waters

Water samples from ponds, lakes, rivers, and private wells are tested for Escherichia coli, commonly known as E. coli, to determine whether it is suitable for irrigation purposes. E. coli is a bacterium that comes from human or animal wastes. The Vermont Department of Health Laboratory (VDHL) performs a test to “quantitate” or count the numbers of E. coli in a water sample to determine its suitability for irrigation. Vermont guidelines for agricultural waters used for irrigation, frost protection, and fertilizer application are based on the Environmental Protection Agency’s recommendations for recreational (swimming) water. Irrigation waters should not exceed 235 CFU/100 ml for E. coli.

The VDHL has the following test types available:

  • Kit AG:Provides Counts of E.coli in irrigation water up to 2000 MPN/100 ml.
  • More information on Kit AG.
  • To request a kit by mail, view/print out our order form and send in with form of payment.
  • Kits can also be purchased in person or over the phone; visit our Contact Us and Directions page for more information.

Guidelines from the Health Department on agricultural water sources.

For more information on irrigation from the University of Vermont Extension.

Legionella

Legionellosis is an infection caused by the bacterium Legionella pneumophila. Outbreaks of legionellosis have occurred after persons have breathed mists from a contaminated water source (e.g., air conditioning cooling towers, whirlpool spas, showers).

Water samples submitted for Legionella pneumophila testing must be linked to a public health investigation and approved/collected by the Vermont Department of Health Environmental Health Division.

More information from the Health Department on Legionellosis.

For more information from the CDC on Legionella click on the topics below: