Grey Bruce Public Health has deemed the Port Elgin Main Beach and Southampton Beach as unsafe for swimming.
This comes after samples collected showed bacterial levels exceeding ministry standards.
Further samples will be taken on Thursday as staff use this water monitoring program each summer to test the water at high use beaches for E. coli levels.
Senior Public Health Manager. Chimere Okoronkwo says swimming in water with elevated bacterial levels can increase the risk of illness or infection.
The no swim advisory will stay in effect until further samples have shown acceptable levels for swimming.
