Mark your calendars: The fluoridation of Portland's water supply is being referred to voters for the May 6, 2014 primary election.

The Multnomah County elections office and the Secretary of State's elections division have validated 33,015 signatures on a petition to halt the fluoridation of Portland reservoirs. That's over a third more signatures than required to make the ballot.

That means the City of Portland won't be able to fluoridate reservoirs until after the 2014 public vote.

"They cannot move forward," says Clean Water Portland organizer Kim Kaminski. "This puts the kibosh on everything."

In August, Portland City Council unanimously approved a fluoridation proposal backed by City Commissioner Randy Leonard and fluoridation advocates Upstream Public Health. The petition drive for a city ballot referrendum began two days later.

The anti-fluoridation activists have also drafted a "Clean Drinking Water Measure" initiative, which would place a fluoridation ban in the city charter. It has survived a legal challenge over the wording, and activists will begin collecting signatures next week.

"The people of the city of Portland care about their drinking water," says Kaminski. "People do not want chemicals in our drinking water. We do not like City Council sneaking this through the back door."