Overview
- Three suburban beaches were closed to swimming on Tuesday, June 23, after routine water samples showed E. coli counts above the Lake County Health Department threshold.
- The affected sites are Elder Park Beach in Winnetka, Rosewood Beach in Highland Park, and Illinois Beach State Park Resort Beach in Zion.
- Lake County collects samples from Lake Michigan beaches four days a week and tests results of 100 E. coli per 100 milliliters or higher trigger notifications and posted closures.
- Park districts and health agencies posted signs and social-media notices that beaches remain open for non-swimming use but that people should avoid entering the water, especially after heavy rain that can raise bacteria through runoff.
- E. coli is used as an indicator of fecal contamination and not all strains make people sick, so officials continue repeat sampling and publish beach-status pages for real-time reopening updates.