Lambton Public Health is encouraging residents with private wells to test their water supply if they experienced flooding during Wednesday's significant rainfall event.
The St. Clair Region Conservation Authority said the watershed received between 50 and 100 millimetres of rain, which resulted in localized flooding in some areas.
The health unit said high levels of rain could cause harmful bacteria to enter the drinking water supply, making it unsafe for consumption.
“Until you can test your well water, use bottled water for daily use including drinking, making infant formula or juices, cooking, making ice, washing fruits and vegetables, and brushing teeth. Alternatively, you can boil your water rapidly for at least one minute before use,” said Public Health Inspector Theresa Warren.
Free water sample kits can be picked up and dropped off at LPH on Exmouth Street in Point Edward, Bluewater Health on Blanche Street in Petrolia, and London Public Health Lab on Highbury Avenue North in London.
Their hours of operation can be found on LPH's website.
Health officials said the well should be disinfected and tested at least three times at one-week intervals once flood waters have receded before water is used for drinking.