Water fluoridation in the United States

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). 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

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