Eighty years ago, Grand Rapids, Michigan became the first city in the United States—and in the world—to decide to add fluoride to its public drinking water. The date was January 25, 1945.
Studies in the 1940s showed that communities whose water naturally contained fluoride had children with far fewer dental problems. Where drinking water lacked natural fluoride, rates of cavities, tooth decay, and enamel damage were noticeably higher. Based on surveys at the time, researchers concluded that fluoridated water could cut tooth decay by as much as 60% and help protect tooth enamel from acids produced by oral bacteria. Fewer cavities meant fewer dental visits and lower costs for families and individuals. Most of us know firsthand how toothaches, gum inflammation, and other oral pain can disrupt work and daily life. From that initial decision in Grand Rapids, community water fluoridation spread across the United States and eventually around the world. Current estimates suggest that roughly 215 million people in about 170 countries now drink fluoridated water—benefiting people across the socioeconomic spectrum.
Because of those public health gains, the U.S. Centers for Disease Control and Prevention (CDC) has long recognized community water fluoridation as one of the great public health achievements of the 20th century. Eighty years later, science and data analysis (including modern computing and long‑term epidemiological tracking) have advanced dramatically, and newer studies are challenging some earlier assumptions about fluoride.
In 2025, the states of Utah and Florida ended water fluoridation, and several other states or local jurisdictions have taken—or are considering—similar actions, reflecting changing public opinion. Adding fluoride is not federally mandated; it is a state or local community choice. After decades in which most Americans consumed fluoridated water, coverage may now contract—at least in portions of the United States. A central catalyst in this shift has been the current Secretary of Health and Human Services, Robert F. Kennedy Jr.
Diverging Views
Robert F. Kennedy Jr. has repeatedly argued that fluoridated water harms human health. Beyond fluoride, he has also questioned established positions on vaccines and is associated with several controversial, widely disputed theories. His position on fluoride is that people already receive it from toothpaste, mouth rinses, certain foods, and in-office dental treatments—so ingesting it through water is unnecessary and potentially harmful. This stands in direct opposition to guidance from the American Dental Association (ADA). For now, however, his viewpoint appears to be gaining ground in some statehouses and local boards that have voted to discontinue fluoridation.
Some water sources naturally contain fluoride; supplementation was traditionally intended simply to bring the level to the recommended 0.7 mg per liter. (The guideline is advisory, not compulsory, and some places have never adopted it.) The CDC acknowledges that extremely high fluoride levels could affect brain development, but stresses that the concentrations used in community water systems are well below those high-risk thresholds.
Secretary Kennedy, in contrast, frames removal as urgent, asserting that evidence shows fluoride may influence children’s neurological development and reduce IQ. He cites a report from the National Institute of Environmental Health Sciences under the Biden administration and a ruling by a federal judge who found that certain fluoride exposures exceed safe limits.
The ADA, unsurprisingly, counters that eliminating water fluoridation will harm oral health, pointing to decades of research backing decay prevention. Opponents respond that adding any chemical—even one historically considered beneficial—diminishes the “natural purity” of water. Their argument: use water as nature provides it; do not “medicate” everyone.
The Controversy
Part of the confusion arises from studies in countries such as India, China, and Iran, where naturally occurring fluoride levels in groundwater can be very high—far above U.S. target levels—and have been associated with neurological effects, including lower measured IQ. Critics of using these studies to guide U.S. policy argue that the data are not directly applicable because of differences in dosage, nutrition, co‑exposures, and methodology. Meanwhile, a federal court in San Francisco recently gave weight to concerns about fluoride’s potential health effects, even though the National Toxicology Program’s assessment has not been fully endorsed by the National Academies of Sciences, Engineering, and Medicine (NASEM). Opponents of fluoridation highlight the court’s stance; supporters dismiss it as insufficient grounds to overturn decades of public health practice.
The ADA’s rebuttal also points out that not everyone reliably uses fluoride toothpaste or mouth rinses, and many rural or low‑income residents have limited dental care access. For these populations, fluoridated water has historically served as an equitable preventive measure.
To date, the CDC has not withdrawn its earlier recognition of community water fluoridation as a landmark achievement. Secretary Kennedy, however, has praised Utah in emphatic terms: “I’m very, very proud of this state for being the first state to ban it, and I hope many more will come.”
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Source Referenced: “Why Fluoride Is Necessary for Public Health” – Johns Hopkins.