Four beaches in Niagara have been posted as unsafe to swim.
Niagara Public Health tests water at 19 beaches across the region.
Waverly Beach in Fort Erie, Long Beach and Reebs Bay - both in Wainfleet- have been posted due to E.coli.
Sunset Beach in St. Catharines was also added to the list this afternoon due to E.coli results.
Levels of E.coli are affected by a number of conditions including birds, wildlife and large numbers of swimmers.
Swimming in these waters could cause infections of the ear, eye, nose, throat and skin as well as cause diarrhea if the water is ingested.