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Learn How to Assess Water Quality to Stay Safe in Vermont’s Waters


September 1, 2020 – Vermont is fortunate to have abundant lakes and streams we can all enjoy. Many people are turning to water-based activities like swimming and boating to practice social distancing while staying cool. We can all safely swim, fish and boat in Vermont’s lakes and ponds if we know what to look for — and what to avoid.

When spending time in and near the water, it is important to know what you’re getting into. The most common water quality concerns for swimmers are E. coli and cyanobacteria. Waterborne pathogens like E. coli can be released into the water after heavy rainfall and can make people sick. Cyanobacteria blooms, sometimes called blue-green algae, are naturally found in freshwater in the U.S. including Lake Champlain and other Vermont waters. Some types of cyanobacteria can release natural toxins or poisons (called cyanotoxins) into the water which can be harmful to people and pets.

You can avoid potentially toxic blooms and E. coli by following these four steps:

  1. Skip the dip after storms: Since heavy rainfall can cause or worsen conditions that can lead to high levels of E. coli, avoid swimming right after a storm. Some swimming holes can also become dangerous following heavy rains and flash flooding.
  1. Know what is and isn’t a bloom: Cyanobacteria blooms can look like pea soup or spilled blue-green paint on the water and can be varied consistencies. To learn what to look for, watch this video from the Department of Health: Know What Grows in Our Lake.
  1. Scan before you swim: Before swimming, take a minute to scan the water for cyanobacteria blooms. If the water is green and scummy, stay out, and keep children and pets away from the shoreline.
  1. Check the map: Use the crowdsourced Cyanobacteria Tracker Map to see where blooms have recently been reported. But remember, conditions can and do change rapidly. You will still need to scan the water for blooms with your own eyes before swimming.

You can report a bloom and share photos using Vermont’s online form. If you are at a public beach, be sure to tell the beach manager or lifeguard too.

For more information, visit these helpful webpages: