Water fluoridation in the United States is common in most states. As of May 2000, 42 of the 50 largest U.S. cities had water fluoridation. On January 25, 1945, Grand Rapids, Michigan, became the first community in the United States to fluoridate its drinking water for the intended purpose of helping to prevent tooth decay.
Fluoridation became an official policy of the U.S. Public Health Service by 1951, and by 1960 water fluoridation had become widely used in the U.S., reaching about 50 million people. By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water, amounting to 61.5% of the total U.S. population. Near the end of 2012, 67.1% of the U.S. population were getting water from community water systems (CWS) supplying water that had fluoride at or above recommended levels. Those included the 3.5% of the population that were on CWS with naturally occurring fluoride at or above recommended levels. 74.6% of those on CWS were receiving water with fluoride at or above recommended levels.
U.S. regulations for bottled water do not require disclosing fluoride content. A survey of bottled water in Cleveland and in Iowa, published in 2000, found that most had fluoride levels well below the 1 mg/L level common in tap waters.
On May 7, 2025 Utah officially became the first US state to implement a ban on fluoridation within their water supplies.
History
Community water fluoridation in the United States is partly due to the research of Dr. Frederick McKay, who pressed the dental community for an investigation into what was then known as "Colorado Brown Stain." The condition, now known as dental fluorosis, when in its severe form is characterized by cracking and pitting of the teeth. Of 2,945 children examined in 1909 by Dr. McKay, 87.5% had some degree of stain or mottling. All the affected children were from the Pikes Peak region. Despite the negative impact on the physical appearance of their teeth, the children with stained, mottled and pitted teeth also had fewer cavities than other children. McKay brought this to the attention of Greene Vardiman Black, and Black's interest was followed by greater interest within the dental profession.
Initial hypotheses for the staining included poor nutrition, overconsumption of pork or milk, radium exposure, childhood diseases, or a [calcium] deficiency in the local drinking water. In 1931, researchers from the Aluminum Company of America (ALCOA) concluded that the cause of the Colorado stain was a high concentration of fluoride ions in the region's drinking water (ranging from 2 to 13.7 mg/L) and areas with lower concentrations had no staining (1 mg/L or less).Meiers, Peter: "The Bauxite Story – A look at ALCOA", from the Fluoride History website, page accessed May 12, 2006. Pikes Peak's rock formations contained the mineral cryolite, one of whose constituents is fluorine. As the rain and snow fell, the resulting runoff water dissolved fluoride which made its way into the water supply.
Dental and aluminum researchers then moved toward determining a relatively safe level of fluoride to be added to water supplies. The research had two goals: (1) to warn communities with a high concentration of fluoride of the danger, initiating a reduction of the fluoride levels in order to reduce incidence rates of fluorosis, and (2) to encourage communities with a low concentration of fluoride in drinking water to add fluoride in order to help prevent tooth decay. By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water, amounting to 61.5% of the total U.S. population; 3.0% of the population on public water systems were receiving naturally occurring fluoride.
In April 2015, fluoride levels in the United States were lowered for the first time in 50 years to the minimum recommended level of 0.7ppm, because excess fluoride exposure had become a common issue for children's teeth, visible in the form of white splotches. This decision was based on the results of two national surveys (1999–2004 NHANES) which assessed the prevalence of dental fluorosis, and found that two out of five adolescents had tooth streaking or spottiness on their teeth - an increase of mostly very mild or mild forms.
On September 24, 2024, a federal judge ordered the U.S. Environmental Protection Agency (EPA) to take regulatory action citing the findings of an extensive federal review of many studies published in peer-reviewed scientific and medical journals showing a dosage-dependent negative impact on children's IQs. District Court Judge Edward Chen ruled that the current recommended fluoridation level of 0.7 ppm "poses an unreasonable risk of reduced IQ in children." The judge based his ruling largely on a comprehensive review of the scientific literature by the U.S. National Toxicology Program (NTP), a federal inter-agency program within the U.S. Department of Health & Human Service (HHS). In determining this unreasonable risk under the Toxic Substances Control Act (TSCA), the court relied on pooled benchmark dose (BMD) modeling, which identified a hazard level—or point of departure—where a 1-point drop in a child's IQ is expected for every 0.28 mg/L of fluoride in a pregnant mother's urine. The court noted that because median maternal urinary fluoride levels in the U.S. are approximately 0.8 mg/L, the safety margin required by standard risk assessment protocols is insufficient or non-existent for pregnant populations.
Early studies
A study of varying amounts of fluoride in water was led by Dr. H. Trendley Dean, a dental officer of the U.S. Public Health Service.Dean, H.T. "Classification of mottled enamel diagnosis." Journal of the American Dental Association, 21, 1421 – 1426, 1934.Dean, H.T. "Chronic endemic dental fluorosis." Journal of the American Dental Association, 16, 1269 – 1273, 1936. In 1936 and 1937, Dr. Dean and other dentists compared statistics from Amarillo, which had 2.8 – 3.9 mg/L fluoride content, and low fluoride Wichita Falls. The data is alleged to show fewer cavities in Amarillo children, but the studies were never published. Dr. Dean's research on the fluoride-dental caries relationship, published in 1942, included 7,000 children from 21 cities in Colorado, Illinois, Indiana, and Ohio. The study concluded that the optimal amount of fluoride which minimized the risk of severe fluorosis but had positive benefits for tooth decay was 1 mg per day, per adult. Although fluoride is more abundant in the environment today, this was estimated to correlate with the concentration of 1 mg/L.
In 1937, dentists Henry Klein and Carroll E. Palmer had considered the possibility of fluoridation to prevent cavities after their evaluation of data gathered by a Public Health Service team at dental examinations of Native American children.Klein H., Palmer C.E.: "Dental caries in American Indian children", Public Health Bulletin, No. 239, Dec. 1937 In a series of papers published afterwards (1937–1941), yet disregarded by his colleagues within the U.S.P.H.S., Klein summarized his findings on tooth development in children and related problems in epidemiological investigations on caries prevalence.
In 1939, Dr. Gerald J. CoxMeiers, Peter: "Gerald Judy Cox". conducted laboratory tests using rats that were fed aluminum and fluoride. Dr. Cox suggested adding fluoride to drinking water (or other media such as milk or bottled water) in order to improve oral health.
In the mid-1940s, four widely cited studies were conducted. The researchers investigated cities that had both fluoridated and unfluoridated water. The first pair was Muskegon, Michigan and Grand Rapids, Michigan, making Grand Rapids the first community in the world to add fluoride to its drinking water to try to benefit dental health on January 25, 1945.After 60 Years of Success, Water Fluoridation Still Lacking in Many Communities. Medical News Today website, accessed February 26, 2006. Kingston, New York was paired with Newburgh, New York. Oak Park, Illinois was paired with Evanston, Illinois. Sarnia, Ontario, was paired with Brantford, Ontario, Canada.
In 1952 Nebraska Representative A.L. Miller complained that there had been no studies carried out to assess the potential adverse health risk to senior citizens, pregnant women, or people with chronic diseases from exposure to the fluoridation. A decrease in the incidence of tooth decay was found in some of the cities which had added fluoride to water supplies. The early comparison studies would later be criticized as, "primitive," with a, "virtual absence of quantitative, statistical methods...nonrandom method of selecting data and...high sensitivity of the results to the way in which the study populations were grouped..." in the journal Nature.Diesendorf, Mark, "The mystery of declining tooth decay" Nature, July 10, 1986
Water fluoridation
As of May 2000, 42 of the 50 largest U.S. cities had water fluoridation.The Benefits of Fluoride, from the Centers for Disease Control and Prevention website, accessed March 19, 2006. According to a 2002 study,Fluoridation Status: Percentage of U.S. Population on Public Water Supply Systems Receiving Fluoridated Water , from the Centers for Disease Control and Prevention website, accessed March 19, 2006. 67% of U.S. residents were living in communities with fluoridated water at that time.
The U.S. Centers for Disease Control has identified community water fluoridation as one of ten great public health achievements of the 20th century. The CDC recommends water fluoridation at a level of 0.7–1.2 mg/L, depending on climate. The CDC also advises parents to monitor use of fluoride toothpaste, and use an alternative water source other than a natural water source with a fluoride concentration above 2 mg/L, for children up to the age of 8. There is a CDC database for researching the water fluoridation status of neighborhood water.
In 1998, 70% of people polled in a survey conducted by the American Dental Association (ADA) believed community water should be fluoridated, with 18% disagreeing and the rest undecided.American Dental Association Survey Center. 1998 consumers' opinions regarding community water fluoridation. Chicago, Illinois: American Dental Association, 1998 In November 2006, the ADA began recommending to parents that infants from 0 through 12 months of age should have their formula prepared with water that is fluoride-free or contains low levels of fluoride to reduce the risk of fluorosis.What is the ADA’s interim guidance on infant formula and fluoride? American Dental Association Website accessed May 28, 2008
The issue of whether or not to fluoridate water supplies frequently arises in local governments. For example, on November 8, 2005, citizens of Mt. Pleasant, Michigan voted 63% to 37% in favor of reinstating fluoridation in public drinking water after a 2004 ballot initiative ceased water fluoridation in the city.Crozier, Stacie. "Michigan town votes to return fluoridation" November 30, 2005. At the same time, voters in Xenia, Ohio; Springfield, Ohio; Bellingham, Washington; and Tooele City, Utah all rejected water fluoridation.
In Skagit County in the state of Washington, the county commissioners in 2007 voted 2 to 1 to order the local public utility district to begin fluoridating the public water supply by Jan. 2009. $1.2 million was to be provided by the privately funded Washington Dental Service Foundation to begin building the equipment needed to add fluoride to the Judy Reservoir, which supplies the majority of Skagit Valley's water customers. The source and type of fluoride to be added to the drinking water of more than 70,000 citizens had not been disclosed. However, in February 2009, Skagit County commissioners rescinded the 2007 order, citing costs and possible lawsuits.