A potential blue-green algae bloom may cause some issues for cottagers and residents on Three Mile Lake.
The Simcoe Muskoka District Health Unit is warning residents to avoid using lake water for food preparation or drinking.
If the algae is toxic it can cause severe symptoms like vomiting, fevers and diarrhea.
You should try to avoid swimming in the lake as well during this time as it may cause itching on the skin and around the eyes.
Blue-green algae blooms generally show up in late summer early fall in shallower water that is warm and lower down in deep cooler water.