Beach Conditions

Beach Alert: When a beach is closed for high bacteria or blue-green algae (cyanobacteria), PHMDC will monitor the beach daily (M-F) until levels decline and the beach can be reopened.

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 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 our Monitoring Beach Health factsheet.


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.

For more tips on staying healthy while swimming and ways to keep our water safe, visit our Healthy and Safe Swimming page.