Fluoride in Drinking Water: A Review of Fluoridation and Regulation Issues

Mary Tiemann
Specialist in Environmental Policy

According to the Centers for Disease Control and Prevention (CDC), 67% of the 246 million people in the United States who receive their water from a public water system received fluoridated water in 2000. One of the CDC's national health goals is to increase the proportion of the U.S. population served by community water systems with "optimally" fluoridated drinking water to 75% by 2010. The decision to add fluoride to a water supply is made by local or state governments. The U.S. Public Health Service (PHS) has recommended an optimal fluoridation level in the range of 0.7 to 1.2 milligrams per liter (mg/L) for the prevention of tooth decay. The fluoridation of drinking water often generates both strong support and opposition within communities. This practice is controversial because fluoride has been found to have beneficial effects at low levels and is intentionally added to many public water supplies; however, at higher concentrations, it is known to have toxic effects. The Environmental Protection Agency (EPA) regulates the amount of fluoride that may be present in public water supplies to protect against fluoride's adverse health effects. Fluoridation opponents have expressed concern regarding potential adverse health effects of fluoride ingestion, and some view the practice as an undemocratic infringement on individual freedom. The medical and public health communities generally have recommended water fluoridation, citing it as a safe, effective, and equitable way to provide dental health protection community-wide.

Because the use of fluoridated dental products and the consumption of food and beverages made with fluoridated water have increased since the PHS recommended optimal levels for fluoridation, many people now may be exposed to more fluoride than had been anticipated. Consequently, questions have emerged as to whether current water fluoridation practices and levels offer the most appropriate ways to provide the expected beneficial effects of fluoride while avoiding adverse effects (most commonly, tooth mottling or pitting—dental fluorosis) that may result from ingestion of too much fluoride when teeth are developing. Also, scientific uncertainty regarding the health effects of exposure to higher levels of fluoride adds controversy to decisions regarding water fluoridation.

Although fluoride is added to water to strengthen teeth, some communities must treat their water to remove excess amounts of fluoride that is present either naturally or from pollution. In 1986, EPA issued a drinking water regulation for fluoride that includes an enforceable standard—a maximum contaminant level (MCL)—and an MCL goal (MCLG) of 4 mg/L to protect against adverse effects on bone structure. EPA acknowledged that the standard did not protect infants and young children against dental fluorosis, which EPA considered a cosmetic effect rather than a health effect. To address this concern, EPA included in the regulation a secondary (advisory) standard of 2 mg/L to protect children against dental fluorosis and adverse health effects. As part of its review of the fluoride regulation, EPA asked the National Research Council (NRC) to review the health risk data for fluoride and to assess the adequacy of EPA's standards. In March 2006, the NRC released its study and concluded that EPA's 4 mg/L MCLG should be lowered. EPA currently is developing a dose-response assessment and updating the relative contribution assessment for fluoride. Once these assessments have been completed and peer reviewed, EPA will be able to determine whether revisions to the drinking water standards would be appropriate.


Date of Report: April 21, 2010
Number of Pages: 22
Order Number: RL33280
Price: $29.95

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