Map of Simcoe Muskoka


Contamination and availability of clean water

Key Messages
Number of Beach Advisories
Number of Confirmed Blue-Green Algae Events
Technical Notes

Key Messages

  • Climate change can impact water quality and water safety as a result of changing temperatures and weather patterns, including drought and rainfall events.
  • Swimming advisories were posted at over two-thirds (72%) of public beaches that were sampled in Simcoe Muskoka in 2022.
  • An increasing number of blue-green algae blooms on bodies of water in Simcoe Muskoka are reported to the health unit each year

Number of beach advisories

  • There were 80 swimming advisories posted in 2022, at 38 out of 53 (72%) public beaches sampled across Simcoe Muskoka.
  • The number of beaches with posted swimming advisories varies each year, from 18 in 2016 to 42 in 2019.


Number of confirmed blue-green algae events per year

  • Twelve blue-green algae blooms were reported in bodies of water across Simcoe Muskoka in 2022.
  • The number of blooms reported to the health unit has been increasing since 2014.
  • Blue-green algae blooms were lower in 2021 and 2022 compared to the spike seen in 2020. However, the number of reported blooms remains higher compared to previous years. There were nearly twice as many reports of blooms in 2022 when compared with 2019.
  • This increase likely reflects increased use of local beaches and waterways during provincial stay-at-home orders.


Technical Notes

The SMDHU and municipal and conservation authority partners monitor select public bathing beaches from June to August each year. A list of beaches included in the monitoring program and their current status is available through the health unit Inspection Connection webpage. Provincial park beaches, such as Wasaga Beach, are monitored by the Ministry of Environment, Conservation and Parks. Beach water quality results for these parks are available on their website.

When advisories are posted for a beach, they will remain in effect until follow-up testing of the water shows that the bacterial contamination is gone. Advisories may remain in effect after several samples.

SMDHU works in collaboration with the Ministry of Environment, Conservation and Parks to assess blue-green algae blooms.

Further Reading

For more about contamination and availability of safe water, see:

Page Last Updated: April 24, 2023.