The Windsor-Essex County Health Unit is warning residents who live near Lake St. Clair about a blue-green algea bloom near Stoney Point.
It tested the water and said the results confirm the algea bloom are pending.
Residents who use the municipal water system can drink the tap water, unless they are advised otherwise.
Those who get their water from a well or cistern that draws water directly from the lake are advised not to drink the water unless they routinely test for microcystins and those results show levels less than 1.5 ppb.
All children under six and infants should only use bottled or municipal water.
The health unit also warns swimmers to stay out of the lake if the water looks cloudy.
Exposure to microcystins can cause itchy, irritated eyes and skin. If swallowed, they make cause headaches, fever, diarrhea, abdominal pain, vomiting, or liver damage.