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Community Water Fluoridation

What is community water fluoridation?

Almost all water contains some naturally-occurring fluoride, but usually at levels too low to prevent tooth decay. Many communities adjust the fluoride concentration in the water supply to a level known to reduce tooth decay and promote good oral health (often called the optimal level). This practice is known as community water fluoridation, and reaches all people who drink that water. Given the dramatic decline in tooth decay during the past 70 years since community water fluoridation was initiated, the Centers for Disease Control and Prevention (CDC) named fluoridation of drinking water to prevent dental caries (tooth decay) as one of Ten Great Public Health Interventions of the 20th Century.

Does my public water system add fluoride to the water?

The best way to find the fluoride level of your local public water system is to contact your water utility provider. Consumers can find the name and contact information of the water utility on the water bill. The U.S. Environmental Protection Agency requires that all community water systems provide each customer with an annual report on water quality, including the fluoride content. If you live in one of the states that participate in CDC's My Water's Fluoride program, you can find information on the fluoridation status of your water system online at My Water's Fluoride.

If I am drinking water with fluoride, why do I also need to brush with toothpaste that contains fluoride?

Both drinking water and toothpaste with fluoride provide important and complementary benefits. Fluoridated water keeps a low level of fluoride in saliva and dental plaque all day. The much higher concentration of fluoride in toothpaste offers additional benefit. Fluoride slows the activity of bacteria that cause decay and combines with enamel on the tooth surface to make it stronger and better able to resist decay. Together, the two sources offer more protection than using either one alone.

Given that we get fluoride from other sources, should communities still fluoridate water to prevent tooth decay?

Yes. Consuming fluoridated water and other beverages and foods prepared or processed with fluoridated water is still important for prevention of decay in a community. Ingesting fluoridated water throughout the day maintains a low level of fluoride in saliva and plaque that enhances the remineralization of weakened tooth surfaces. Community water fluoridation has been identified as the most cost-effective method of delivering fluoride to all members of the community regardless of age, educational attainment, income level, and the availability of dental care. In studies conducted after other fluoride products, such as toothpaste, were widely available, scientists found additional reductions in tooth decay – up to 25 percent – among people with community water fluoridation as compared to those without fluoridation.

Has the safety of community water fluoridation been evaluated?

The safety and effectiveness of fluoride at levels used in community water fluoridation have been thoroughly reviewed by multinational scientific and public health organizations (U.S., Canada, Australia, New Zealand, Great Britain, and the World Health Organization) using evidence-based reviews and expert panels. These panels include scientists with expertise in various health and scientific disciplines, including medicine, biophysics, chemistry, toxicological pathology, oral health, and epidemiology.

Experts have weighed the findings and quality of available evidence and concluded that there is no association between water fluoridation and any unwanted health effects other than dental fluorosis.

Are there any harmful health effects due to community water fluoridation?

The safety and effectiveness of community water fluoridation continues to be supported by scientific evidence produced by independent scientists and summarized by panels of experts. The independent, non-governmental Community Preventive Services Task Force has noted that the research evidence does not demonstrate that community water fluoridation results in any unwanted health effects other than dental fluorosis, a condition that causes primarily cosmetic changes in the appearance of tooth enamel.

Will using a home water filtration system take the fluoride out of my home's water?

Removal of fluoride from water is a difficult water treatment action. Most point-of-use treatment systems for homes that are installed on single faucets use activated carbon filtration, which will not remove the fluoride ion. Other treatment systems (such as reverse osmosis, ion exchange, or distillation systems to reduce fluoride levels) vary in their effectiveness to reduce fluoride. Check with the manufacturer of the individual product.

Will boiling or freezing reduce the fluoride level in water?

Fluoride is not released from water when it is boiled or frozen. One exception would be a water distillation system. These systems heat water to the boiling point and then collect water vapor as it evaporates. Water distillation systems are typically used in laboratory installations. For home use, these systems can be expensive and may present safety and maintenance concerns.

Will water fluoridation result in pipe corrosion or increased lead in drinking water?

Water fluoridation will not increase pipe corrosion or cause lead to leach from pipes and household plumbing fixtures. Although lead in public drinking water is typically found to be very low or is below laboratory detection, there are locations where old lead pipes, solder, or plumbing fixtures in old homes may experience leaching of lead into water. Claims by some that fluoride might result in increased lead leaching from pipes and fixtures have not been substantiated in the peer-reviewed literature.

What did the 2015 report from the Cochrane Oral Health Group say about the effectiveness of water fluoridation?

The Cochrane review found that water fluoridation is effective in reducing cavities in primary and permanent teeth in children. It found that water fluoridation resulted in fewer teeth affected by cavities (about 2 primary teeth and 1 permanent tooth), compared to communities that did not have water fluoridation. These differences indicated that initiation of water fluoridation could result in decreases of up to 35% in cavities in children. In addition, water fluoridation resulted in higher percentages of children without any cavities (caries-free).

Cochrane’s restrictive methodology for including studies in their analyses excluded the majority of studies done after 1975. Although valid, peer-reviewed studies clearly document the effectiveness of community water fluoridation in children and adults even after the use of fluoride toothpaste, these studies were not considered by Cochrane. As a result, Cochrane found insufficient information available to determine if water fluoridation had an impact in an environment where fluoride products such as toothpaste are now widely used.

Another factor that impacted Cochrane’s assessment of the evidence is that their methodology favors randomized controlled trials (RCTs). While RCTs are a preferred study design for studies comparing different clinical treatments among individual patients, this research design is often not feasible for interventions that occur on a community level, like community water fluoridation.