Fluoride is a mineral that appears naturally in soil, water, air and certain foods. It is often added to public drinking water to help prevent tooth decay and is considered a cost-effective method of delivering fluoride to all members of the community. The Centers for Disease Control and Prevention (CDC) recommends drinking fluoridated water along with using fluoride products (e.g., fluoride toothpaste) on a regular basis as part of good dental hygiene.

Fluoride was first added to community drinking water in the United States in 1945. Studies of its effects over a 15-year period found that fluoridated water reduced tooth decay in children by 60 percent. According to the CDC, as of December 31, 2000, almost 66 percent of the United States population receives public drinking water that is fluoridated.

The optimal range for fluoride levels in drinking water is between 0.7 (for warmer climates) and 1.2 (for cooler climates) parts per million (ppm) or milligrams per liter, according to the U.S. Public Health Service. Drinking water with levels of fluoride above 2 ppm may cause dental fluorosis in children. This may be more likely to occur in communities that do not regulate fluoride levels in the water, or among those who rely on well water with naturally occurring high levels of fluoride. Community water that is fluoridated is monitored daily to ensure that proper levels of fluoride are maintained.

Most people support water fluoridation. However, people who oppose it have questioned its safety and argued that it is a decision imposed upon them by others.