Water Fluoridation

What is water fluoridation?

Community water fluoridation (CWF) adds a controlled amount of fluoride to the water supply to prevent dental caries (cavities).^[1] Dental caries are caused by acid-producing bacteria that remove minerals from the surface of a tooth, resulting in tooth decay.^[2] Fluoride prevents tooth decay by keeping tooth enamel strong, providing a protective barrier against harmful bacteria.^[2] While fluoride occurs naturally in the water supply, the concentration is usually not sufficient to prevent dental caries.^[3] Community water fluoridation reaches everyone in the community regardless of age, education, income level, or access to routine dental care.

What is the public health issue?

Dental caries are one of the most common chronic diseases in children and adolescents. Among adults aged 20–64, 91 percent had dental caries and 27 percent had untreated tooth decay.^[4] CWF has been a major contributor to the dramatic decline of tooth decay in the U.S. in the 1900s.^[2] CDC declared community water fluoridation one of the ten greatest public health advances of the twentieth century.^[5] However, about 100 million Americans still do not have access to water with sufficient levels of fluoride to optimally prevent tooth decay.^[6] As part of Healthy People 2020, the U.S. has set a goal to have 80 percent of Americans served by community water systems with optimal fluoridation by 2020—a 10 percent increase from 2008.^[7]

What is the evidence of health impact and cost effectiveness of CWF?

A systematic review of water fluoridation literature found that the prevalence of caries was substantially lower in communities with CWF and that the prevalence of new caries increases when CWF was discontinued.^[3] A combined evidence review (systematic reviews and additional studies) showed a 15 percent decrease in caries following initiation of CWF, with the prevalence of caries reduced across all socioeconomic groups.^[8] Additionally, there is no evidence that community water fluoridation results in severe dental or medical adverse effects.^[3]

CWF provides cost-savings for large and small communities. An economic review of multiple studies found that benefits ranged from $1.10 to $135 of benefit for every $1 invested.^[9] Per capita annual costs for CWF ranged from $0.11 to $24.38, while benefits ranged from $5.49 to $93.19. ^[9] Benefit to cost ratios increase as the size of the community increases.^[9]

For questions or additional information, email healthpolicynews@cdc.gov.