Other locations sampled in Rock County this week included Lake Koshkonong and Clear Lake, both of which were below health advisory levels, according to the release.
The high levels of E. Coli bacteria mean swimmers and others playing in the river could become ill if they ingest surface water.
Officials say recent rains may have led to water runoff that’s contributing to the high bacteria levels.
Current Rock County beach and surface water sampling information can be found at http://www.co.rock.wi.us/health-water-beaches. For more information, you can contact the Rock County Public Health Department at 757-5440 or 364-2010.