The Windsor Essex County Health Unit has closed one beach in the region and posted warnings against swimming at another.
Lakeshore Lakeview Park West Beach is closed. E.coli counts hit 1000 this week.
Over at Colchester Beach, the e.coli count was 681, enough for the health unit to post a warning against swimming.
Open and safe for swimming this weekend are Cedar Beach, Cedar Island Beach, Holiday Beach, Point Pelee North West Beach, and Seacliff Beach.