CORNING — A petition calling for city charter changes that would prohibit Corning from fluoridating its water has enough valid signatures to trigger a referendum, City Clerk Rose Blackwell said Friday.

Blackwell said the petition contained 320 valid signatures — 14 more than the 306 needed to force a vote.

“I’m very pleased with this excellent news,” said Kirk Huttleston, the fluoride opponent who led the petition drive. “It was very close.”

Blackwell said the petition contained 432 signatures, 112 of which were invalid.

She said she spent three days at the Steuben County Board of Elections checking the signatures against voter registration lists.

To force a vote next year on the charter changes, Huttleston needed the signatures of 10 percent of city residents who voted in the 2006 gubernatorial election.

Blackwell said the city vote in that election totaled 3,057.

Some of the reasons for which signatures were invalidated, Blackwell said, included:

•The signer was not a city resident.

•The signer was not a registered voter until after the 2006 gubernatorial election.

•Names were printed rather than signed.

•Some signers witnessed their own signatures, which is not permitted.

•Some signers provided an incomplete addresses.

“I knew there were a lot of different ways that a signature could be disqualified,” Huttleston said, “but I didn’t know what they were.”

The petition now goes to the Corning City Council for review before it is sent to the Steuben County Board of Elections.

The City Council voted 7-1 in May to add fluoride to the city’s water supply to reduce the incidence of tooth decay. It has not taken any action toward carrying out the project.

City Manager Mark Ryckman said the referendum would likely be held in November 2008.

Ryckman said the city’s schedule called for fluoridating its water in 2009 at the earliest in connection with installing a new disinfection system.

Ryckman said the success of the petition hasn’t changed the direction he received from the City Council.

“The council wants me to pursue fluoridating the water,” he said.

The petition campaign was based on a similar one that was successful in Ithaca in 2000.

Fluoride supporters, including former Corning dentist Dr. Thomas Curran, have said they will try to block a vote on the issue.