Beach water quality can change rapidly from day to day or even hourly depending on the weather and other factors including nearby pollution sources such as rivers and streams which is why Toronto’s designated beaches are sampled daily and tested for bacterial levels.

However, due to the delay in receiving lab results (usually 24 hours), beach users cannot simply rely on only lab results when considering swimming at a beach and are encouraged to make an informed decision about beach water quality before swimming at designated beaches.  The following information will help you assess the beach water quality during your visit and before deciding to swim at a beach of your choice:

• Rain: Rainfall has a significant impact on beach water quality since rain washes contaminants from surfaces into streams, rivers and lakes.  The first few minutes of surface water runoff during a rainfall can be the most polluted while small amounts of rainfall are unlikely to have much impact on beach water quality, swimming should be avoided for 24 to 48 hours after heavy rain. 
• Wind: Wave action on any body of water can stir up sand and silt making the water cloudy, especially with significant waves. During such condition, bacteria levels may be higher if you can’t see your feet standing waist deep in water. 
• Waterfowl: These include gulls and geese that can release feces can deteriorate beach water quality by increasing bacterial levels. 
• Wet Sand and Shallow Water: Shallow bodies of water are likely to be warmer and bacteria levels can increase quickly in warm temperatures and tend to be higher in wet sand as well.  Be sure to use a hand sanitizer or wash hands if washrooms are available after playing at the edge of the water. Reminder: Never swallow beach water no matter how clear the water looks!