Blue-Green Algae Bloom Confirmed North-West Three Mile Lake in the Sandwood Road Area – August 21, 2023

The Ministry of the Environment, Conservation and Parks (MECP) has confirmed a blue-green algae bloom in Three Mile Lake, specifically in its Northwest region near Sandwood Road.

Blue-green algae, also known as cyanobacteria, can produce toxins detrimental to human and animal health in high concentrations. With the confirmation of this bloom, residents and visitors are urged to be cautious, as harmful toxins might also be present in the water.

For safety, the Simcoe Muskoka District Health Unit (SMDHU) recommends the following precautions for residents and businesses:

▪ Avoid using water from private supplies affected by the lake where the algae has been detected, especially for preparing infant formula.

▪ Keep pets and livestock away from water where visible algae blooms are present, both for drinking and swimming.

▪ Be cautious when consuming fish caught in waters with visible cyanobacterial blooms due to potential toxin contamination.

▪ Refrain from using herbicides, copper sulphate, or other algaecides, as they could rupture algae cells, releasing more toxins.

▪ Stay clear of water sport activities in areas with visible algae blooms.

The health unit, in collaboration with the MECP, will continuously monitor the situation. For updates, please check the SMDHU website:

For more details, reach out to Health Connection from Monday to Friday, 8:30 a.m. to 4:30 p.m. at 1-877-721-7520. Additional resources and updates on blue-green algae can be found at


Township of Muskoka Lakes notice can be found here.