A total water ban was put into effect in Stratford, Ont. on Monday after a chemical spill contaminated the southwestern Ontario city's supply.

Residents were advised not to drink the water or even wash their hands after a car wash company doing maintenance work on its plumbing system spilled detergents and waxes into the pipes.

City engineer Tom Crozier said the company was using a pressure washer to clean out its pipes Monday morning. Then, a malfunctioning valve allowed the dirty water that spilled into a grate to flush back into the city's water mains.

Perth County's medical officer of health, Dr. Rosanna Pellizzari, issued an emergency water advisory at noon ET after an area resident complained of pink water coming out of her taps.

The advisory was expected to extend until Tuesday, pending environment ministry test results.

"We don't believe the risk to be that great," said Pellizzari. "These are irritants. At most they will cause some irritation of the throat and some stomach upset."

Stratford mayor Dan Mathieson said, "It's safe to say that we're being very cautious with regards to this. It's something that we take very seriously. It's our drinking water."

Ontario's environment ministry, along with local public utilities officials and the health unit, are trying to determine exactly what chemicals were spilled into the water.

"Certainly, our staff are doing all that we can to ensure that whatever resources we have are best used to support this circumstance," said Ontario Environment Minister Leona Dombrowsky in Toronto.

Stratford General Hospital didn't report any water-related illnesses by late afternoon.

The medical officer's warning set off a rush on bottled water at supermarkets. Stores had to arrange tractor-trailer loads of bottled water to be shipped in after supplies disappeared within an hour of the announcement.

The owner of Festival City U-Wash told CTV's Kitchener affiliate, CKCO News, that it was an accident, and that he had plumbers by early afternoon fixing the faulty valve.