Fluoride in Drinking Water: 2025 and Beyond
In 1999, the Centers for Disease Control and Prevention (CDC) recognized the fluoridation of drinking water as one of the “ten greatest public health achievements of the 20th Century.” The practice has reportedly reduced tooth decay in children by 40-70% and tooth loss in adults by 40-60%. According to the CDC, one year of providing fluoridated water in the United States saves an estimated $6.5 billion in averted direct and indirect dental treatment costs. However, recently the CDC and the EPA has been asked to evaluate removing fluoride from the drinking water supply.
What do we know about fluoride, its benefits in preventing tooth decay, and its health risks?
History of Fluoride
Fluoride is a naturally occurring inorganic trace mineral found in air, water, soil, plants, and human bones and teeth. Fluoride research dates back to the early 1900s when scientists observed that higher concentrations of fluoride in the drinking water of some communities correlated with symptoms of fluorosis, a mottled condition in the enamel of teeth, but also reduced levels of tooth decay. Scientists hypothesized that adding fluoride to drinking water in proper amounts could protect teeth from decay while also mitigating the risk of fluorosis.
Subsequent controlled studies, including Dr. H. Trendley Dean’s 1945 study of the first community water fluoridation program in Grand Rapids, Michigan, firmly established the practice of water fluoridation as a practical, safe, and effective public health measure to prevent tooth decay. Scientists now understand that fluoride works by preventing the loss of certain minerals which protect the outer layer of teeth, restoring them with a fluoride-containing mineral resistant to acid attacks and hindering bacterial activity.
Soon after local governments began fluoridating water, private companies explored the addition of fluoride to dental products. In the early 1950s, Proctor & Gamble initiated human clinical trials to study the impact of incorporating fluoride in toothpaste. In 1955, the company commercialized the first fluoride enhanced toothpaste marketed as "Crest with Fluoristan."
Today, fluoride is generally regarded by the Food and Drug Administration (FDA) as safe for use in consumer care products. Government health agencies currently support the fluoridation of public water supplies with the CDC reporting that roughly 73% of the U.S. population drinks fluoridated water.
How Much is Safe?
According to the National Institutes of Health (NIH), the safe daily dose of fluoride for an adult is 10 mg. However, the safe daily level varies by age and sex. Estimating daily fluoride intake in the average American can be challenging as fluoride is consumed from various sources beyond drinking water, including dental products and common foods. The volume of water consumed per person, the concentration of fluoride in individual public water supplies, and even the amount of toothpaste used by an individual can all have an impact. Studies have shown that children brushing their teeth twice daily can consume between 0.6 and 0.9 mg of fluoride. In adults, 50% of fluoride consumed is retained in the body with 99% of it being stored in bones and teeth.
Despite the challenges in accurately estimating daily fluoride consumption, the CDC continues to recommend a concentration of 0.7 mg/L of drinking water as safe.
Potential Health Risks of Fluoride
High doses of fluoride have been reported to be lethal when exposure was in the range of 40-80 mg/kg of body weight. In addition, excessive long-term exposure to fluoride can result in both dental and skeletal fluorosis, which is caused by mineral deficiency in the bone. However, the condition is reversible with proper treatment. Fluorosis is most common in countries where fluoride levels in the water supply exceed 4 mg/L, much higher than U.S. standards.
Recent studies, primarily in foreign countries such as Canada, China, India, Iran, Pakistan, and Mexico where pregnant women, infants and children receive total fluoride exposure amounts higher than 1.5 mg/L in drinking water, have examined whether elevated fluoride exposure can result in developmental and neurological harm to children. A similar study was also conducted in the United States. Several of these studies have reported a correlation between elevated or excess exposure (greater than recommended standards) to fluoride and lower child IQ scores, though findings are not consistent across all research.
The studies prompted the National Toxicology Program (NTP) of the U.S. Department of Health and Human Services (DHHS) to release a 2024 report stating with “moderate confidence,” that “higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children.” The NTP noted that there is insufficient data to determine whether exposure within recommended safe levels has the same negative effect on child IQ or whether fluoride exposure has adverse effects on adult cognition. Accordingly, the NTP recommends additional research “to better understand if there are health risks associated with low fluoride exposures.”
Litigation Surrounding Marketing of Fluoridated Dental Products
Recently, several lawsuits have been filed against manufacturers of fluoride-containing dental products for children. The lawsuits claim that fluoride is dangerous to children in elevated doses and that the industry has failed to properly warn of the danger while marketing products with child-friendly colors, flavors, and labels. The FDA generally regards fluoride as safe for use in such products but requires standard warning labels. However, the lawsuits argue that the labels are insufficient in light of the marketing practices that appeal to children.
Current Developments
Although fluoridation is commonplace, it is not federally mandated. Recommendations from the CDC could influence state and local governments to stop their fluoridation programs.
At a press conference held on April 7, 2025, U.S. Health Department announced plans to stop recommending fluoridation in communities nationwide and directed the CDC to reconvene an independent panel to examine fluoride’s role in water sources. The Environmental Protection Agency, charged with ensuring drinking water quality in the United States pursuant to its authority under the Safe Drinking Water Act, has similarly announced plans to review the safety of fluoride.
Two states, Utah and Florida, have passed laws banning fluoride from municipal drinking water. Studies from two other jurisdictions that removed fluoride from their water systems showed a measurable impact on oral health. After Juneau, Alaska discontinued fluoride in 2007, cavity-related dental procedures subsequently increased by nearly 50 percent in children and adolescents. In Canada, after the city of Calgary removed fluoride in 2011, subsequent research found that children had more tooth decay compared to Edmonton, which maintained fluoridation. Calgary is currently in the process of reintroducing fluoride.
The American Academy of Periodontology (AAP), and the American Dental Association (ADA) both continue to advocate for the use of fluoridated water and dental products in the population to mitigate gum and tooth disease. Following Secretary Kennedy’s press conference on April 7, 2025, the ADA issued its own press release stating: “Eighty years of community water fluoridation at optimal levels has proven to be safe and effective at reducing tooth decay to improve oral health.” The ADA cited an Australian study finding that fluoridation in water supplies at current recommended levels in the U.S. and Canada “had no measurable effect on cognitive neurodevelopment or IQ scores in children.” The ADA concluded that “[t]o prevent dental disease and promote overall health the ADA continues to recommend drinking optimally fluoridated water along with twice daily brushing with fluoride toothpaste and eating a healthy diet, low in added sugars.”
To date, the CDC has not officially changed its recommendation of adding fluoride to the water supply at a concentration of 0.7 mg/L.
As the national conversation around fluoride continues to evolve, the balance between public health benefits and potential risks remains at the forefront of policy discussions. While decades of research and endorsements from leading health organizations support the safety and efficacy of fluoridation, recent legal challenges, shifting political perspectives, and emerging studies have reignited scrutiny. The decisions made in the coming years—by federal agencies, state legislatures, and local communities—will shape the future of oral health in the United States.
Authored by Chris Dorko, Berkley Life Sciences, VP, Risk Management Resources Officer