Cherry Beach in Toronto is generally one of the cleanest mainland beaches in the city, but like all urban beaches, its water quality is subject to E. coli fluctuations, particularly after heavy rainfall. The City of Toronto's "Blue Flag" program monitors E. coli levels daily during the swimming season (June through Labour Day). In early 2026, the water quality is typically "Safe" for swimming, but the city will issue a "Caution" or "No Swimming" advisory if the E. coli count exceeds 100 per 100 ml of water. High E. coli levels are usually caused by stormwater runoff, which flushes bird droppings and urban contaminants into the lake. You can check the "live" status of Cherry Beach on the City of Toronto’s SwimSafe website or the Swim Guide app. Even if the beach looks clear, it is a standard safety rule to avoid swimming for at least 24 to 48 hours after a major storm. Outside of the summer monitoring season (like right now in March), the water is not officially tested for E. coli, so swimming is "at your own risk," though the extreme cold of Lake Ontario is usually a more immediate deterrent for most people.