Nearly all naturally occurring water sources contain fluoride—a mineral
that has been proven to prevent, and even reverse, tooth decay.
Tooth decay is caused by certain bacteria in the mouth. When a person eats
sugar and other refined carbohydrates, these bacteria produce acid that
removes minerals from the surface of the tooth. Fluoride helps to
remineralize tooth surfaces and prevents cavities from continuing to form.
In the 1930s, dental scientists documented that the occurrence and
severity of tooth decay was lower among people whose water supplies
contained higher levels of natural fluoride. Extensive studies followed and
discovered that fluoride, when present in the mouth, can become concentrated
in plaque and saliva, helping to prevent the breakdown of enamel minerals.
In 1945, the city of Grand Rapids, Michigan, added fluoride to its municipal
water system. Community water fluoridation—adjusting the amount of fluoride
in an area’s water supply to a level that helps to prevent tooth decay and
promote oral health—had begun. Since then, numerous scientific studies and
comprehensive reviews have continually recognized fluoridation as an
effective way to prevent tooth decay.
Benefits of Fluoridation
Water fluoridation prevents tooth decay mainly by providing teeth with
frequent contact with low levels of fluoride throughout each day and
throughout life. Even today, with other available sources of fluoride,
studies show that water fluoridation reduces tooth decay by about 25 percent
over a person’s lifetime.
Community water fluoridation is not only safe and
effective, but it is also cost-saving
and the least expensive way to deliver the benefits of fluoride to all
residents of a community. For larger communities of more than 20,000 people,
it costs about 50 cents per person to fluoridate the water. It is also
cost-effective because every $1 invested in this preventive measure yields
approximately $38 savings in dental treatment costs.
This method of fluoride delivery benefits all people―regardless of age,
income, education, or socioeconomic status. A person’s income and ability to
get routine dental care are not barriers since all residents of a community
can enjoy fluoride’s protective benefits just by drinking tap water and
consuming foods and beverages prepared with it.
Fluoride from other sources prevents tooth decay as well, whether from
toothpaste, mouth rinses, professionally applied fluoride treatments, or
prescription fluoride supplements. These methods of delivering fluoride,
however, are more costly than water fluoridation and require a conscious
decision to use them.
Currently, more than 204 million people in the United States are served
by community water supplies containing enough fluoride to protect teeth.
Even so, approximately 100 million Americans do not have access to
fluoridated water. Healthy People is the plan that sets health goals for the
nation. This plan calls for 79.6 percent of the population to be served by
optimally fluoridated community water systems by 2020. The current
population with access to fluoridated water is 73.9 percent.
The widespread availability of fluoride through water fluoridation,
toothpaste, mouth rinses, and other sources, however, has resulted in the
steady decline of dental caries throughout the U.S.
Community Water Fluoridation:
Questions and Answers
Community Water Fluoridation Fact Sheets
Date last reviewed: April 27, 2012
Date last updated: April 27, 2012
Division of Oral Health,
National Center for Chronic Disease Prevention and