Utah becomes first state to ban water fluoridation

Utah has become the first US state to ban the decades-old practice of adding fluoride to public water supplies, due in part to a mix of health concerns about the practice.

Utah Gov. Spencer Cox signed the new law on Thursday, prohibiting fluoridation starting May 7. The move comes amid growing scrutiny of the practice, which started in the 1940s as a strategy to help people prevent cavities and reduce tooth decay.

Though more than 70% of the US population receives fluoridated public water supplies and many medical professionals support the practice, opposition has been growing due to studies suggesting fluoride may have neurotoxic effects on fetuses and young children.

Newly appointed Health and Human Services Secretary Robert F. Kennedy Jr. has been calling for an end to fluoridation in public drinking water for years.

Some professional bodies remain ardent supporters of the practice, however. The American Dental Association issued a statement on Friday accusing Utah lawmakers and the governor of showing “wanton disregard for the oral health and well-being” of state residents.

“There is substantial evidence to show that when fluoridation ceases, dental disease increases,” the ADA said.

The new state law specifies that “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 … a public water system.”

Michael Connett, a lawyer with many years of experience litigating cases related to fluoride, said that in banning the practice, “Utah has followed the path of most advanced nations, which have already ended water fluoridation.”

“While fluoridation has long been a sacred cow in the US, the reality is that there are far safer, and more effective, ways of using fluoride than adding it to water,” he said, such as brushing with fluoride toothpaste and spitting it out.

The effects of ceasing fluoridation are not clear cut.

A 2024 Cochrane meta-analysis, the gold standard for assessing evidence-based health interventions, found that there was insufficient data to determine if ending fluoridation caused cavities to increase in any given area.

It also found very little evidence of effectiveness. Studies conducted after 1975 show the practice may reduce levels of decayed, missing or filled teeth by 3% to 4%, but that the practice may also provide “no benefit.”

The most recent meta-analysis of studies on fluoride’s safety, published in January in JAMA Pediatrics, found exposure to fluoride is linked with declines in children’s IQ, including at low urinary levels commonly found in fluoridated communities.

Some researchers who have studied fluoridation said the move was warranted.

“I think it is prudent to end water fluoridation until an independent scientific committee has had ample time to review the evidence indicating that fluoride is neurotoxic and water fluoridation does not appear to effective at reducing dental cavities,” said Bruce Lanphear, an expert on environmental neurotoxins and a health sciences professor at Simon Fraser University in Vancouver.

Lanphear cited the January 2025 JAMA Pediatrics paper and the Cochrane review to support his statement.

Philippe Hujoel, a dentist and epidemiologist at the University of Washington, said he also thinks that it is reasonable to cease fluoridation until a randomized controlled trial (RCT) shows that it is both effective and safe. “We’re in 2025, and we still don’t have an RCT on fluoridation,” Hujoel said. The evidence we do have “doesn’t look very good” for effectiveness and “you have these safety concerns.”

Bills to ban water fluoridation are also in the works in Florida and Montana. Legislative committees in New Hampshire, North Dakota, and Arkansas rejected bills in recent weeks that would ban fluoridation.

(Featured image by Arthur Shuraev via Unsplash+.)