Kennebunk, Kennebunkport & Wells Water District customers will soon drink fluoridated water.

Residents of the seven towns served by the water district – from York to Biddeford Pool – voted Tuesday to add the chemical to the water supply. The measure won in each town and passed with 61 percent of the vote.

Overall, fluoride received 8,004 votes in favor and 5,192 votes against.

Support for fluoridation was strongest in Biddeford, where 79 percent of voters approved. Only the section of Biddeford east of Route 9 is served by KKW, and only that section of the city voted on the measure.

Support for fluoridation was weakest in Wells, where the measure passed by just 29 votes out of 3,809 votes cast.

Dentist Lisa Howard was happy to hear the results. She moved to Kennebunk from Minnesota and was surprised to learn that the water lacked fluoride. She rallied dentists, who asked town councils and boards of selectmen in the KKW service area to put fluoridation on this year’s ballot.

“I’m very pleased,” Howard said this morning. “I’m sure my fellow dentists are pleased as well.”

Adding the chemical will cost KKW $100,000 for a storage space addition and $25,000 annually in operating costs, according to KKW Superintendent Norm Labbe. That’s small change in KKW’s $4 million annual operating budget, he said, and won’t force a rate increase.

“In nine months, we’ll be providing fluoride,” Labbe said this morning.

The American Dental Association has endorsed fluoridation and the Centers for Disease Control called it one of the “great public health achievements of the 20th century.”

Howard said, “We’ll see the effects (from the fluoridation) in a couple of years. I think it will make a significant difference.”

Opponents have waged successful campaigns against water fluoridation in other parts of the country, but no organized opposition came forward in York County.