The U.S. Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. invited controversy when he instructed the Centers for Disease Control and Prevention (CDC) to stop advising adding fluoride to drinking water. The Environmental Protection Agency (EPA), which doesn’t fall under RFK Jr.’s leadership, establishes standards for fluoridation and the safety of public water systems. Neither the EPA nor HHS requires fluoride to be added to water systems across the United States.
(How safe is your water? Here are some tell-tale signs.)
RFK Jr. has long advocated for the removal of fluoride from drinking water because he believes fluoride is an “industrial waste” linked to conditions such as arthritis, bone fractures, thyroid disorders, and neurodevelopmental disorders (per CNN). However, many of these claims are based on unsafe fluoride levels in drinking water. For example, a 2024 monograph by the National Toxicology Program found that drinking water with more than 1.5 milligrams of fluoride per liter was linked to lower IQ scores in children. Although the EPA allows public water to have up to 4 milligrams per liter, the current HHS standard is 0.7 milligrams per liter.
How safe is fluoride?
While RFK Jr. is correct that some industries release fluoride into the environment during manufacturing, fluoride is also a naturally occurring element in the earth, according to a 2018 article in Preventive Nutrition and Food Science. Fluoride is stored in your bones and teeth, where it helps strengthen bone-building cells. Although fluoride occurs naturally in some water systems, the United States and Canada began adding it to public water supplies in the 1940s to help prevent cavities. It worked, and fluoride was later added to dental products like toothpaste and mouthwash.
Problems can arise when someone consumes too much fluoride. Most cases of fluoride toxicity in children happen when they swallow toothpaste or drink mouthwash. Fluoride toxicity in adults is rare, but it can occur when the fluoride concentration in drinking water is too high. Severe fluoride toxicity can lead to bone fractures, and joints and tendons may lose mobility.
RFK Jr. also claims that fluoridated water causes thyroid disorders. A 2024 meta-analysis in Environmental Research reviewed 27 studies on the link between fluoride exposure and thyroid disease. It found that high levels of fluoride, especially above 2.5 milligrams per liter, are associated with increased levels of thyroid-stimulating hormone (TSH) in the blood, which can be a sign of thyroid dysfunction.
Adding fluoride to water is optional for states and local governments
State and local governments are not required to add fluoride to drinking water, but the CDC currently recommends a concentration of 0.7 milligrams per liter to help prevent cavities. Voters in each community can choose to limit or increase fluoride levels, as long as they don’t exceed the EPA’s maximum limit of 4 milligrams per liter. Water systems with naturally high fluoride concentrations due to the environment must reduce fluoride to safe levels. EPA Administrator Lee Zeldin said he will work with RFK Jr. to review current research on fluoridated water and may reconsider the standards under the Safe Drinking Water Act. Remember, the EPA also keeps an eye on toxic chemicals like PFAS that can be found in your drinking water.
In Utah, state legislators recently passed a bill that would ban the addition of fluoride to public water systems even though the CDC shows less than half of Utah residents currently receive fluoridated water (via NBC News). Four other states have introduced similar bills that would either make fluoridation optional or prohibit additives like fluoride in water altogether.
