Back to today’s briefing

Story perspectives

Ontario Warns: E. Coli Levels Make Swimming Risky

6/24/2025

22 3

Summary

Story summary

Ontario's Ministry of Health has issued a stark warning: swimming becomes dangerous when E. coli levels hit 400 per 100 millilitres or a geometric mean of 200 in five samples. Factors like rain, waves, and pollution can further compromise beach safety, with elevated E. coli levels potentially signaling the presence of toxic blue-green algae and other harmful organisms.

1 of 1

Story summary

Ontario's Ministry of Health has issued a stark warning: swimming becomes dangerous when E. coli levels hit 400 per 100 millilitres or a geometric mean of 200 in five samples. Factors like rain, waves, and pollution can further compromise beach safety, with elevated E. coli levels potentially signaling the presence of toxic blue-green algae and other harmful organisms.