Water is necessary for all bodily functions. In addition, water treated with fluoride has become an essential part of maintaining good oral health. Fluoride is a mineral that helps strengthen teeth and protects them from decay. Most U.S. communities now add fluoride to their water systems.

Fluoridation of community water supplies enables fluoride to routinely enter the mouth. Dental plaque absorbs some of this fluoride. Fluoride from water also rests loosely on dental enamel and remains in saliva for a period of time. Fluoridation of the water supply is estimated to reduce tooth decay by between 20 percent and 40 percent, according to the American Dental Association (ADA).

People obtain their daily water supply from different sources. For many years, tap water has been the primary source of water for most people. However, in recent years increasing numbers of Americans have begun to get their daily water from sources other than the tap. Such sources include bottled water, water machines, and water that is filter treated at home. In many cases, these alternative sources of water do not offer the same fluoridation benefits as tap water.

Few brands of bottled water add fluoride to their water, and the majority fail to contain optimal levels (0.7 to 1.2 parts per million) of fluoride necessary to protect teeth, according to the ADA. In addition, some home water treatment systems actually reduce the amount of fluoride in tap water, although others do not.