After months of delay, water taps in many parts of San Diego County will begin flowing with fluoridated water tomorrow.

What is fluoridation?

Fluoridation is the addition of a chemical to water to prevent tooth decay. The Metropolitan Water District, which supplies water to Southern California, will be using fluorosilicic acid to provide fluoridation.

Why is the county getting fluoridated water now?

The Metropolitan Water District decided in 2003 to begin fluoridating its water supply while upgrading its treatment plants.

The district had planned to start fluoridating the treated water it sends to the county in July but delayed it while dealing with construction problems at the facility that serves the county, the Robert A. Skinner plant in Temecula.

The district began fluoridation Oct. 29, with the Skinner plant last on the schedule. Spokesman Bob Muir said yesterday that fluoridation will begin at the Skinner plant tomorrow as planned.

Which areas of the county will receive fluoridated water?

Cities and water agencies that buy treated water from the district will receive fluoridated water. Some customers, such as the city of San Diego, buy treated and untreated water, so the amount of fluoridation will vary among neighborhoods.

Four county agencies that buy only untreated water and treat it themselves will not be fluoridated: the city of Poway, Sweetwater Authority, the Santa Fe Irrigation District and Camp Pendleton. The Sweetwater Authority says it might buy fluoridated water in an emergency.

For a map of fluoridation levels around the county, go to [link below]. For information about the process, go to [link below].

Call your local water agency to determine if your area will be getting fluoridated water.

What are the benefits and concerns about fluoridation?

Proponents call fluoridation “dental insurance in a glass” and say the process reduces cavities and keeps children healthier.

“We feel it’s just really, really fantastic. And it’s an extremely low cost to keep it going,” said Eleanor Nadler, executive director of the San Diego Fluoridation Coalition, which supports the process.

Opposition has ranged from concerns that fluoridation is an unnecessary government intrusion and causes countless diseases, to more extreme claims of plots to poison the public.

Jeff Green, the San Diego-based national director of Citizens for Safe Drinking Water, which opposes fluoridation, said fluorosilicic acid is not safe and is inadequately tested.

What if I use bottled water or a home filtration device?

Many bottled waters have a less-than-optimal level of fluoride, considered to be 0.7 to 0.8 parts per million. Call the consumer service number on the bottle’s label to ask how much fluoride is in the water.

Water distillation units and reverse osmosis systems remove significant amounts of fluoride.

Should I give fluoridated water to my infant?

High levels of fluoride can cause dental fluorosis, a discoloration of the teeth, in young children. The American Dental Association recommends using nonfluoridated water for infants.

Are there plans for other areas in the county to get fluoridated water?

Last month, a commission headed by county Supervisor Ron Roberts voted to allocate $5.7 million in tobacco tax dollars to begin fluoridation at seven water districts, starting with the city of San Diego.

The cost for the city to fully fluoridate hasn’t been determined.