Public Health Launches New Rapid Beach Water Testing this Summer


This week, Public Health Madison & Dane County kicked off its annual beach monitoring season. During the summer months each year, Public Health monitors conditions and tests the water at local beaches to make sure it is safe for swimming.

“Under the right conditions, harmful bacteria and toxins like blue-green algae and E. coli, can grow quickly in the shallow waters along local beaches,” says Jennifer Lavender-Braun, Microbiologist for Public Health Madison & Dane County. “New this summer, we’ll be incorporating rapid testing methods that will allow us to report results faster and test more days of the week.”

The new rapid testing system uses a method that detects bacteria in water samples within 2-4 hours compared to the traditional method that provides results within 18 hours.

“Beach days in Wisconsin are limited, so by getting these more real-time results, we’re able to re-open beaches faster following a closure to help families enjoy swimming safely,” said Lavender-Braun.

Nearly two dozen Dane County beaches are sampled every week. Crews run the samples through various tests and then check the results. Swimmers can find the test results and beach closures updated online daily or have a daily digest emailed directly by subscribing to the email list.

“We are also piloting a predictive system that will allows us to pre-emptively close certain beaches where heavy rainfall is known to result in elevated levels of bacteria. This will allow us to be proactive rather than waiting for test results,” said Lavender-Braun.

If unsafe levels of bacteria are detected, the beach is closed for swimming and staff will retest the water each weekday until levels return to normal.

Some other general advice for swimmers this summer:

  • Conditions can change quickly. Do not swim in water that looks like "pea soup", green or blue paint, or that has a scum layer or puffy blobs floating on the surface, even if you don’t see closure signs posted.
  • Always look at the water before letting a dog swim or wade and rinse them off as soon as possible after they are in the water.
  • If you have been in water with blue-green algae, rinse off well and monitor yourself for symptoms of illness.
  • Avoid swimming after a heavy rain because bacteria levels in the water may be high.

Report a blue-green algae bloom or illness to the Wisconsin Harmful Algal Blooms Program (WI DHS) or contact Public Health by phone at (608) 266-4821 or email at

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