Beach Water Quality

Beach Alert: We monitor water quality at beaches from Memorial Day to Labor Day. Check conditions before entering the water, avoid contact with blue-green algae, and stay out of the water if posted signs say “closed for swimming.”

Olin BeachMemorial Day to Labor Day, we test water at the beaches listed below for E.coli bacteria and cyanobacteria (blue-green algae) and their toxins to protect swimmers and other recreational water users. If a water test shows concerning results, the beach will close for swimming until levels of E. coli bacteria or blue-green algae By clicking this link, you will be leaving the City of Madison website. decline.

For more information on how we test, see How We Monitor Beach Water Quality.


Beaches are treated as all other outdoor spaces and under all phases of our Forward Dane Plan and are allowed to be open with physical distancing. Individual gatherings within the beach need to comply with the 'outdoor mass gatherings in public venues.' Which means at this time, an individual group cannot be larger than 25 people (with distancing) but there can be more than 25 people at the beach.

Before swimming, always take an overall look at water conditions. Conditions can change quickly, and testing results may not always reflect real-time water quality. A few things to be aware of:

  • Swimming is not advisable after a heavy rainfall because bacteria levels in the water may be high.
  • Avoid contact with blue-green algae blooms which appear blue-green, green, reddish-purple, or brown, and cause the water to be murky. Blue Green Algae Precautions.

Request Testing for Your Water Event

If you are hosting an event where people will be in the water, you might consider additional testing for E.coli and blue-green algae. See our fact sheet for different options and costs. Contact us at 608-266-4821 to schedule services.