POLK COUNTY — The Polk County Health Department has issued a water advisory on South Twin Lake and Clear Lake due to high levels of Escherichia coli (E.coli). The water advisory will remain in effect until tests are returned with appropriate levels; testing is conducted weekly.
High levels of the bacteria were confirmed in tests from samples collected on June 10, 2026. Wisconsin State Statute, 254.46, gives local health departments the authority to restrict swimming if a human health hazard exists.
Natural bodies of water can occasionally contain elevated bacteria levels due to rain, runoff, or other environmental factors. Elevated bacteria levels can increase the chance of illness, including:
- Sore throat or respiratory infection
- Diarrhea or bloody stool
- Ear, eye, and skin infections
- More serious conditions such as meningitis and hepatitis
All warm-blooded animals, such as humans, birds, dogs, and cows, have E. coli bacteria in their excrement. High amounts of E. coli found in water is often due to large numbers of birds near the water, failing septic systems, or runoff from fields treated with livestock manure. Conditions can significantly vary hour-to-hour and day-to-day. Polk County residents should be encouraged to check conditions before entering the water and to swim at their own risk. There is always a risk of bacteria in a lake.
For more information about swimming beach monitoring and safety, you can call the Polk County Health Department at 715-485-8400. Updates regarding water advisories in Polk County can be found here.
Last Update: Jun 12, 2026 4:59 pm CDT
