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Fluoride and Drinking Water: Implications for Kansas Communities
Hill to the Heartland: Federal Health Policy Briefing
Ensuring access to fluoride in drinking water to prevent tooth decay has been a public health goal for decades, but the debate over the benefits, costs, optimal levels and risks of fluoridation has led Kansas to trail its neighboring states in the percentage of the population with access to fluoridated water. Those debates may resurface, particularly now that U.S. Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. has stated he plans to tell the Centers for Disease Control and Prevention (CDC) to stop recommending fluoridation in community public water systems and announced that he will be assembling a task force to study the issue. On the same day, the U.S. Environmental Protection Agency (EPA) announced that it is reviewing “new scientific information” on the potential health risks of fluoride in drinking water and specifically referred to the National Toxicology Program Report released in August 2024. Under the federal Safe Drinking Water Act of 1974, the EPA is authorized to establish minimum standards to protect tap water and requires all owners or operators of public water systems to comply with these primary, health-related standards. These standards include setting the maximum level of fluoridation in public water systems.
The Current Federal Fluoride Recommendations
Fluoridating water, as a public health practice, has been recommended by the federal government for decades. After a team of scientists from the University of Pittsburg proposed adding fluoride to drinking water to prevent tooth decay in 1939, the city of Grand Rapids, Michigan, became the first city to add fluoride to its water supply in 1945. When the first children to drink fluoridated water since infancy began to reach school age, dentists in Grand Rapids reported a significantly lower number of cavities among those children starting school in 1949. A year later the American Dental Association, the Association of State and Territorial Dental Directors, and the U.S. Public Health Service (USPHS) all issued statements endorsing community water fluoridation. As of 2022, the CDC estimates that 72.3 percent of the U.S. population that is connected to community water systems receives fluoridated water, or 62.8 percent of the U.S. population overall.
Under current law, the federal government does not have legal authority to require state and local communities to fluoridate their water or to remove fluoridation. These decisions are made at the state and local level. However, the EPA does set the maximum level of fluoridation in public water systems to protect against risks from excessive exposure to fluoride. In addition to setting a “primary” standard for water fluoridation levels, the EPA also sets a “secondary non-enforceable” standard. Legal action can be taken against a water provider if the fluoride level exceeds the primary standard, but exceeding the secondary standard does not trigger any legal or federal action. The current EPA primary fluoride standard, which was set in 1986, is 4.0 milligrams-per-liter (mg/L). A milligram per liter is also equal to one part contaminant to one million parts water. The EPA’s secondary “recommended” level is no more than 2.0 mg/L.
In addition to the EPA standards, the CDC provides recommendations for achieving public health benefits from fluoridation. The current CDC guidelines, which were last updated in 2015, recommend an “optimal fluoride concentration” of 0.7 mg/L in community water systems, significantly lower than the EPA standards. Prior to 2015, the CDC recommendation was 1.2 mg/L. Since 1962, the USPHS has recommended the addition of fluoride to community water systems to reduce the risk and severity of dental caries, one of the most common chronic diseases in children. The CDC determines what fluoride concentration in drinking water is optimal for the prevention of cavities based on USPHS recommendations.
National Toxicology Program Report
The EPA announcement on April 7 referred to a National Toxicology Program (NTP) report published in August 2024. The NTP Monograph on the State of Science Concerning Fluoride Exposure and Neurodevelopment and Cognition: A Systematic Review (and an Addendum) evaluates the evidence of an association between exposures to fluoride and human neurodevelopment (development of the human nervous system) and cognition (the mental process of thinking and learning). The Monograph includes studies involving children and adults and studies of potential mechanisms. Most of the studies examine intelligence quotients (IQs) of children with higher estimates of fluoride exposure compared to children with lower estimates of fluoride exposure and fluoride exposures from many sources including drinking water, prepared beverages, foods and dental products. The children’s IQ studies presented in the Monograph were performed in 10 countries, including Mexico and Canada. None of the studies were conducted in the United States. The Monograph and Addendum do not address whether the sole exposure to fluoride added to drinking water, such as the 0.7 mg/L in the United States and Canada, is associated with a measurable effect on IQ and do not provide an estimate of the number of IQ points lost for a given increase in fluoride exposure measures.
The studies on adults in the NTP Monograph are limited and provide low confidence that fluoride exposure is associated with adverse effects on adult cognition. However, the review found, with moderate confidence, that higher fluoride exposures — for example, above 1.5 mg/L, more than twice the current CDC recommendation — were associated with lower IQ scores in children. The authors of the NTP Monograph recommend targeted research in the United States to examine the association between fluoride exposure and children’s IQ in optimally fluoridated areas of the U.S. — with levels of 0.7 mg/L — to add clarity to the existing data.
Fluoridation in Kansas
As of 2024, 63.9 percent of Kansans served by community water systems receive fluoridated water. This places Kansas 33rd among states and below the Healthy People 2030 goal of 77.1 percent. Healthy People 2030 is an initiative of the HHS Office of Disease Prevention and Health Promotion that provides evidence-based, 10-year measurable objectives to improve health and well-being. One of the objectives is community water fluoridation as a proven strategy to prevent tooth decay and promote oral health. Kansas has a lower proportion of the population with access to fluoridated public water than other states in the region (Figure 1). Iowa exceeded the Healthy People 2030 goal, with 88.8 percent of the population receiving fluoridated public water as of 2024. Missouri, Colorado and Nebraska are near the 77.1 percent goal with 76.7 percent, 74.5 percent and 74.1 percent, respectively.
Figure 1. Water Fluoridation Status in Kansas and Neighboring States, 2024
Access to fluoridated water systems also varies across the state, with each county having unique distribution through city water systems, rural water districts and other utility authorities. Of the 105 counties in Kansas, 25, primarily in Central Kansas, do not have fluoridated water (Figure 2). There are 38 counties that meet the Healthy People 2030 goal with 77.1 percent of the population receiving access to fluoridated public water. Of the 861 water systems in Kansas, 295 have access to fluoride either naturally or through the addition of fluoride.
Figure 2. Percent of the Population Served by Fluoridated Public Water Systems by Kansas County, 2024
Note: 77.1% represents the Healthy People 2030 goal for the percentage of people served by water systems with the recommended level of fluoride.
Source: 2024 CDC Water Fluoridation Statistics.
Recently, the City of Abilene in Dickinson County considered eliminating its fluoride ordinance. After the Abilene City Commission, in a 3-2 vote, repealed the ordinance on April 24, 2024, it reinstated it three weeks later on May 16, 2024, following testimony from two local dentists, the Executive Director of the Kansas Dental Association, the Executive Director of Oral Health Kansas and a private citizen.
A timeline of the history of fluoridation is provided below.
Figure 3. Fluoridation – A Timeline
1901 – Dentists in the U.S. and Italy separately observe lower rates of dental decay in populations with distinctively stained teeth.
1931 – A U.S. Public Health Service officer and founder of the Dental Hygiene Unit at the National Institutes of Health determines that “mottled enamel” is caused by too much fluoride intake and renames the condition “dental fluorosis.”
1939 – A team of scientists from the University of Pittsburg publish a paper proposing the controlled addition of fluoride to drinking water to prevent tooth decay.
1945 – Grand Rapids, Michigan, becomes the first city to implement water fluoridation and begins adding a carefully controlled amount of sodium fluoride to the city’s water supply.
1949 – The first children to drink fluoridated water since infancy begin reaching school age. Dentists in Grand Rapids and other communities report a sharply lower number of cavities among the children starting school in 1949.
1950 – The American Dental Association, Association of State and Territorial Dental Directors, and the U.S. Public Health Service all issue statements endorsing community water fluoridation.
1954 – The total number of Americans receiving fluoridated tap water passes 20 million.
1956 – Crest, the world’s first fluoride toothpaste, is released nationally.
1962 – Federal drinking water standards are updated to include fluoride guidelines with recommended maximum levels. The optimal fluoride concentration ranged from 0.7 ppm to 1.2 ppm, contingent on the local climate, accounting for higher water consumption in warmer climates.
1969 – As the U.S. population surpasses 200 million, 43.7 percent of Americans have access to fluoridated tap water. A survey by the U.S. Public Health Service examines over 1,000 community water supplies, revealing inadequate state oversight of public water systems and inconsistent water quality.
1972 – The Clean Water Act gives the EPA responsibility for developing mandatory standards to control water pollution and the authority to enforce those standards.
1974 – The Safe Drinking Water Act grants the EPA authority over drinking water quality, enforcing legally binding standards for all U.S. public water supplies. The Act designates drinking water fluoridation as a state, not a federal, responsibility.
1978 – The U.S. Surgeon General moves the National Fluoridation Program to the Centers for Disease Control and Prevention (CDC).
1980 – Half of the U.S. population receives fluoridated tap water.
2012 – Fluoridated water is supplied to three-quarters of Americans (74.6 percent) through public water systems, while 67.1 percent of the overall U.S. population has access to fluoridated tap water.
2015 – Based on the widespread availability of fluoride in drinking water and oral care products, along with considerations of dental fluorosis trends and evidence on fluid intake in diverse climates, the U. S. Public Health Service simplifies recommendations for optimal fluoride concentration. The new guidance advises community water systems to adopt a uniform concentration of 0.7 mg/L of fluoride in drinking water, ensuring cavity prevention benefits while minimizing the risk of dental fluorosis.
Funding for Hill to the Heartland is provided in part by the Sunflower Foundation: Health Care for Kansans, a Topeka-based philanthropic organization with the mission to serve as a catalyst for improving the health of Kansans. KHI retains editorial independence in the production of its content and its findings. Any views expressed by the authors do not necessarily reflect the views of the Sunflower Foundation.
About Kansas Health Institute
The Kansas Health Institute supports effective policymaking through nonpartisan research, education and engagement. KHI believes evidence-based information, objective analysis and civil dialogue enable policy leaders to be champions for a healthier Kansas. Established in 1995 with a multiyear grant from the Kansas Health Foundation, KHI is a nonprofit, nonpartisan educational organization based in Topeka.