The DO NOT USE water advisory remains in effect for those in Grey Highlands and West Grey who use water from Irish Lake.
The Grey Bruce Health Unit put out the advisory last Wednesday after blue green algae was discovered around the lake water.
Medical Officer of Health Doctor Hazel Lynn says they will test the algae to determine whether it has the deadly toxin .
She says until that is confirmed no one is to use water from Irish Lake for drinking, cooking, washing, or bathing.
Doctor Lynn says it will be some time before they get the test results back.
She says the last time they had to test for algae was in Lake Rosalind in 2007 and that took at least four or five days.
The blue green algae may contain Cynobacteria — a toxin which may be harmful to human health and to the health of animals.