The Windsor-Essex County Health Unit says nine of 10 beaches in the area are not safe for swimming.
The only location approved for swimming is Hillman Beach in Leamington.
Based on water samples taken on Wednesday, swimming is not recommended at these beaches: Cedar Island Beach - Kingsville, Northwest Beach - Point Pelee, Sandpoint Beach - Windsor, West Belle River Beach - Lakeshore.
Cedar Beach - Kingsville, Colchester Beach - Essex, Holiday Beach - Amherstburg, Lakeside Beach-Kingsville, and Seacliff Beach - Leamington are closed because the bacteria have reached a health hazard level of more than 1000.
The next water samples will be taken on Wednesday and results will be posted by Friday. Beach water sampling will continue until September 11.
The sample results take up to two days to process because they are sent to a public health lab in London.
The bacterial counts given reflect the conditions at the time of sampling. Conditions change from day to day depending on the weather conditions and lake levels, says the health unit.
