The San Francisco Public Utilities Commission--which provides 44 percent of Sunnyvale's water--recently completed work on a $5 million fluoridation plant in Sunol. The plant is on the pipeline that brings water to the Bay Area from the Hetch Hetchy reservoir in Central California.

"The completion of that project made us physically able to provide fluoride to all of our customers," SFPUC spokeswoman Betsy Rhodes said.

The SFPUC was slated to begin adding fluoride to all the water it provides to the Bay Area by the middle of September, but nationwide shortages in fluoride--caused by increased use and the loss of a supplier--have pushed that date back to later this fall.

According to Lin, fluoride is especially important for children because it is a factor in the strong, healthy growth of teeth. In addition, it strengthens all teeth and kills some bacteria that cause tooth decay.

Although fluoride helps protect against tooth decay, Lin stressed that good dental care is still needed, and too much fluoride can have negative effects on teeth. Because of that Lin said that once fluoride is in a water system, residents are typically advised to discontinue use of fluoride pills or other fluoride supplements.

But not all residents will be pleased with the move. Fluoride has been the focus of national controversy. According to fluoridealert.com, Environmental Protection Agency workers' unions are calling for a ban on fluoridation because they say the chemical is a possible cancer risk.

"Anything in excess is not good," Lin said. "When you have fluoride in the water, you don't need to get it elsewhere."

According to www.fluoridealert.org, too much fluoride can cause a condition called dental fluorosis. In mild cases, this leads to discoloration off the teeth, but severe cases can result in broken, damaged teeth.

But Lin said for the majority of residents, fluoride in the water will help by providing the chemical--a naturally occurring substance--to those who don't get it now, and save money for those who currently pay for it.

Lin was concerned about how much good the fluoride would do because people have to drink tap water to get it.

"Nowadays, people drink more from water bottles," he said. "Sources like that don't have fluoride in them."