Municipal Drinking Water Systems:

Municipal drinking water systems are routinely monitored for blue-green algae and microcystin, a specific cyanotoxin with known health effects. Both the raw water and treated water are tested regularly in addition to visual monitoring of the lake and intake lines. Most municipal systems in Canada have never exceeded the maximum acceptable concentration of microcystin in treated water. This tells us that the complex treatment systems used by most municipal drinking water systems are effective at removing blue-green algae and their toxins.

Residents will be notified immediately if microcystin test results for treated water exceed the Ontario Drinking Water Quality Standard. The risk of exposure of cyanotoxins from municipal drinking water is very low.

Residential and Private Drinking Water Systems:

During peak season, usually June-October, home and cottage owners should visually monitor lakes and rivers for evidence of blue-green algae bloom. Home treatment systems may not remove toxins from the water and the water may not always taste or smell bad, so be cautious and take the following precautions:

• Do not drink the water or use it for food preparation, including infant formula.
• Use an alternate source of safe drinking water, such as bottled water, for the duration of the bloom.
• Do not boil and drink water that may contain blue-green algae because toxins are not destroyed by boiling and boiling my increase toxins.
• Do not use herbicides, copper sulphate or other algaecides that may break open algae cells and release toxins into the water.
• Bathing or showering with water not visibly affected by a blue-green algae bloom is not expected to cause health effects.