Blue-Green Algae

Pond covered by algae

The Wisconsin Division of Public Health collects information about human and animal illness resulting from exposure to blue-green algae. Tracking illness information will help the Wisconsin Division of Public Health measure the problem of blue-green algae in our lakes and rivers.

If you get sick after swimming in a Wisconsin lake or river, please report possible algae-related illness. This program does not provide medical treatment, so if you are experiencing severe symptoms seek medical attention immediately.


Please report any blue-green algae blooms and related human or animal illnesses to the Wisconsin Harmful Algal Blooms Program by calling 608-266-1120 or completing the Harmful Algae Bloom (HAB) Illness or Sighting Survey (WebSurvey).


When in doubt, stay out!


Last Revised: July 6, 2017