Kelso Beach at Nawash Park in Owen Sound has been deemed unsafe for swimming.
Samples taken from the water returned with high levels of bacteria on Friday, which exceeded Ontario Ministry of Health standards.
“While the weather forecasted for this weekend looks favourable for swimming, Grey Bruce Public Health advises against doing so at Kelso Beach due to high bacteria levels, likely caused by the recent heavy rainfall,” said Grey Bruce Public Health Senior Public Health Manager Andrew Barton.
The beach will remain open, but people shouldn't swim or play in the water until the no-swimming advisory is lifted.
The Good Cheer Splash Pad remains open since it uses municipal treated water.