In a statement of claim filed Thursday in Brampton, Ont., Liesa Cianchino claims risks posed by water fluoridation greatly exceed its benefits.
Cianchino further claims that water fluoridation violates both the Canadian Charter of Rights and Freedoms and the Ontario Safe Drinking Water Act.
A longtime resident of Mississauga, Ont., Cianchino is chairwoman of Concerned Residents of Peel to End Water Fluoridation.
Her claims argues that fluoride works topically on the teeth and that nothing is gained by ingesting it through drinking water.
Cianchino's claims have not been tested in court, and representatives for Peel Region and Ontario could not be reached for comment.
"We can't continue to allow outdated science to contaminate our drinking water," Cianchino said.
"Our health and our environment are at risk. We deserve safe drinking water."
The claim states more than 70 per cent Ontario residents drink fluoridated water, compared to just three per cent of the population in western Europe.
Lawsuits against fluoridating water supplies have been filed in several cities across North America in recent years.