The water at three beaches should be considered unsafe for swimming, according to the Windsor and Essex County Health Unit.
Swimming is not recommended at Mettawas, Point Pelee North West and Seacliff beaches.
The health unit says water samples taken Monday indicate high levels of E.coli bacteria, which could pose a risk to your health.
Officials remind swimmers the bacterial count reflects conditions at the time of sampling, and water quality can change from day to day.
