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Why is fluoride added to drinking water?

All water naturally contains some fluoride. Fluoride leaches into the water from fluoride-containing rock formations. Studies have shown that consumption of water containing 1 mg of fluoride per liter of water (mg/L) can result in 17-40% fewer cavities in permanent teeth. Since most community water supplies naturally contain less than 1 mg/L of fluoride, to provide dental benefit, fluoride must be added. Water fluoridation is very cost effective. According to the National Center for Disease Control, the average cost to fill one cavity is $42, which is approximately how much it costs to provide fluoridation of drinking water to a person for a lifetime. At the levels present in drinking water, fluoride does not affect the color or taste of the water.

Does the Acton Water District add fluoride to drinking water?

Yes. The Water District adds a small amount of sodium fluoride to the water at each well to raise the concentration to approximately 1.0 mg/L, a level that will best protect teeth.

Are there any health risks of too much fluoride?

Yes. Although it is necessary to humans in small amounts, fluoride can be harmful in large amounts. The Environmental Protection Agency (EPA) has set the Maximum Contaminant Level (MCL) for fluoride at 4.0 mg/L. Prolonged exposure to levels of fluoride exceeding this MCL can cause skeletal fluorosis, a serious and crippling bone disorder. In addition, children exposed to levels of fluoride over 2.0 mg/L for an extended period of time may develop dental fluorosis, a brown staining or pitting of their permanent teeth. Dental fluorosis can only occur if developing teeth (teeth that have not yet erupted from the gums) are exposed to high levels of fluoride. In a recent study, the National Cancer Institute concluded that fluoridated water is in no way associated with cancer risk.

What is the typical level of fluoride in Acton’s water?

The Acton Water District’s water generally contains approximately 1.0 mg/L fluoride, ranging from 0.95 mg/L to 1.11 mg/L. At 1.0 mg/L, the level of fluoride is high enough to significantly reduce tooth decay, but it is still well below the level (2.0 mg/L) where it has been known to stain children’s teeth.