(SALT LAKE CITY) — Utah Gov. Spencer Cox signed a bill this week making the state the first in the nation to ban fluoride in public drinking water.
Under the bill, a person “may not add fluoride to water in, or water that will be introduced into a public water system” and a “political subdivision may not enact or enforce an ordinance that requires or permits the addition of fluoride to water in, or water that will be introduced into, a public water.”
The bill does allow pharmacists in the state to prescribe fluoride supplements and directs the Division of Professional Licensing to establish guidelines for those prescriptions.
Cox had previously indicated that he would sign the bill. The law is set to go into effect on May 7.
Fluoride is a mineral that naturally occurs in water sources such as lakes and rivers, and is even naturally present in some foods and beverages, according to the American Dental Association (ADA).
It is added to some dental products, such as toothpaste, to help prevent cavities.
High-quality studies show fluoride prevents cavities and repairs damage to teeth caused by bacteria in the mouth. Fluoride makes tooth enamel stronger and rebuild weakened tooth enamel, the ADA says.
Fluoride also replaces minerals lost from teeth due to acid breakdown, according to the Centers for Disease Control and Prevention.
However, influential skeptics such as Health and Human Services Secretary Robert F. Kennedy Jr. have long raised doubts about the benefits of fluoride.
In an interview with NPR in November 2024, Kennedy doubled down on his promise of persuading local governments to remove fluoride from their water supplies.
He has claimed that fluoride in drinking water affects children’s neurological development and that other countries that have removed fluoride from their water supplies have not seen an increase in cavities.
A large review paper published in January 2025 suggested a link between fluoride and lower IQ in children, but much of the underlying data was pulled from other countries, where fluoride exposure is far higher than levels used in drinking water in the U.S.
Some health professionals have also expressed concerns about excessive fluoride intake and potential toxicity.
Many doctors and dental associations, however, argue that fluoride in water is still a crucial, low-risk/high-reward public health tool, especially for disadvantaged children and adults who may not be able to practice regular dental hygiene.
In a letter asking Cox to veto the bill, the ADA said that Utah health department data shows communities with fluoridated water had decreasing rates of dental disease.
The association calls community water fluoridation “the single most effective public health measure to prevent tooth decay.”
“Studies prove water fluoridation continues to be effective in reducing dental decay by at least 25% in children and adults, even in the of era widespread availability of fluoride from other sources, such as fluoride toothpaste,” the ADA states on its website. “So, by simply drinking fluoridated water, you are doing something good for your oral health.”
ABC News’ Sony Salzman contributed to this report.
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