Fluoride in drinking water

Many cities add fluoride to water to prevent cavities. Here is what federal agencies, a 2024 federal review, and recent state laws say, in their own words.

The federal limits

• EPA's enforceable limit: 4.0 mg/L. EPA lists the concern as "Bone disease (pain and tenderness of the bones); Children may get mottled teeth" (EPA).
• EPA's secondary standard: 2.0 mg/L, for tooth discoloration. Utilities above it must give public notice. (EPA)

The 2024 federal review of IQ studies

The National Toxicology Program reviewed the research in August 2024 (NTP):

• NTP concluded, "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."
• "There were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children's IQ."
• "The NTP found no evidence that fluoride exposure had adverse effects on adult cognition."

What EPA is doing now

On April 7, 2025, EPA announced it would "expeditiously review new scientific information on potential health risks of fluoride in drinking water" (EPA). As of October 2, 2026, the limits above have not changed.

State laws

• Utah, since May 7, 2025: "A person may not add fluoride to water in, or water that will be introduced into, a public water system." (HB 81)
• Florida, since July 1, 2025: SB 700 limits what public water systems may add to a "water quality additive" as the law defines it. (SB 700)

Check your own water

• City water: your utility's yearly water quality report lists fluoride. (EPA)
• CDC's My Water's Fluoride tool shows many community systems. CDC says your utility is the best source for your level.
• Private well: find a water test near you. Many lab panels include fluoride.
• Results back? Check a fluoride result.

If you want less fluoride

Reverse osmosis and distillation reduce fluoride. Compare home fixes.

Sources checked October 2, 2026. This page reports what official sources say. It is not medical advice.