Recreational use of Rock County waterways and beaches continues to increase. Users should be aware of current water quality issues before heading out to enjoy a day of fun.

E. coli bacteria occur naturally in surface water, however, as levels increase, there is an increased risk of human and pet illness due to recreational activities when water can become ingested. Recent rainfall, as well as land runoff, can affect E. coli levels in water testing results, especially during flooding.

Rock County beaches and waterways are sampled for E. coli from May through September. Campground beaches and the Rock River are sampled weekly as they have the highest human use. Nineteen other locations are site sampled at boat launches and bridges on a monthly or annual basis to track trends on E. coli levels. Licensed beaches are “closed” at 1,000 CFU (colony forming units). Water quality advisory signs are posted at beaches that test 235 CFU or greater. Surface waterway advisories are issued at 1,000 CFU, as water may not be suitable for recreational activities due to the potential for ingestion of water.

Local Information & Data

• Water Testing Results 
• Algal Bloom Watch
• Frequently Asked Questions

Additional Resources

• WI DHS Flood Hazards & Recovery
• US Geological Survey
• Water Safety at Lakes/Beaches
• Flooding Reference