Fluoride in Water: What It Is, Why It's Added, and the Limits
Fluoride in water is the fluoride your tap water contains, whether or not your water system adds it. The U.S. Public Health Service recommends 0.7 mg/L for community water systems that add fluoride. EPA's enforceable maximum contaminant level (MCL) for fluoride is 4.0 mg/L, and its health goal (MCLG) is also 4.0 mg/L.
Key numbers
0.7 mg/L
U.S. Public Health Service recommendation
The U.S. Public Health Service recommends 0.7 mg/L for community water systems that add fluoride.
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1.5 mg/L
WHO guideline value
The World Health Organization's guideline value for fluoride in drinking water is 1.5 mg/L.
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1.5 mg/L
National Toxicology Program (2024)
NTP's 2024 monograph concluded, with moderate confidence, that drinking water containing more than 1.5 mg/L is associated with lower IQ in children.
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2.0 mg/L
EPA secondary standard (non-enforceable)
EPA's secondary (non-enforceable) standard for fluoride is 2.0 mg/L, and exceeding it requires a special public notice.
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4.0 mg/L
EPA maximum contaminant level (enforceable)
EPA's enforceable maximum contaminant level (MCL) for fluoride is 4.0 mg/L, and its health goal (MCLG) is also 4.0 mg/L.
Verified
How to check your water's fluoride
CDC's My Water's Fluoride site gives general information on fluoridated water systems, for the states that choose to provide it, and names your local water provider (utility) as the best source of information on fluoride levels in community water systems.
Under EPA's Consumer Confidence Report rule, a community water system's water quality report, its Consumer Confidence Report (CCR), must give each detected regulated contaminant with its MCL and MCLG, the highest level detected and the range of detected levels. Fluoride has an EPA MCL, so it is one of those regulated contaminants.
Our ZIP check shows the fluoride level each water system serving a ZIP code reported, where our data has one.
What fluoride in water is
Almost all water contains some naturally occurring fluoride, but usually at levels too low to prevent cavities.
This page gives every fluoride level in milligrams per liter (mg/L).
When fluoride in a water system exceeds 2.0 mg/L, the system must notify its customers of the increased potential for dental fluorosis.
The levels in our data are the ones utilities report. They do not show whether a system adds fluoride or whether the fluoride was already in its source water.
Why fluoride is added to water
The U.S. Public Health Service recommends 0.7 mg/L for community water systems that add fluoride, to maintain fluoride's tooth-decay prevention benefits while reducing the risk of dental fluorosis.
Grand Rapids, Michigan became the first city in the world to fluoridate its drinking water, in 1945. In 2022, 62.8% of the U.S. population received fluoridated water.
Where federal and state policy stands
EPA committed on April 7, 2025 to an expedited review of fluoride under the Safe Drinking Water Act, released a Preliminary Assessment Plan and Literature Survey on January 22, 2026, and released a Protocol for Developing the Fluoride Human Health Toxicity Assessment on August 3, 2026. As of 2026-10-11, EPA's Fluoride in Drinking Water page does not mention a proposal or proposed rule to change the fluoride MCL.
On October 31, 2025, FDA recommended that ingestible fluoride drug products be limited to children aged 3 and older at high risk for tooth decay.
CDC continues to recommend community water fluoridation at the concentration the Public Health Service recommends, describing it as a cornerstone strategy for preventing tooth decay.
As of 2026-10-11, our state-law review lists Florida and Utah as statewide bans, as the National Conference of State Legislatures does. The National Conference of State Legislatures' fluoride snapshot, updated September 24, 2025, names Utah and Florida as the first states to enact laws prohibiting the addition of fluoride in public water systems. Florida's SB 700 (2025) prohibits any additive in a public water system that does not meet the statute's definition of a water quality additive (one used to meet drinking water standards, remove contaminants or improve water quality). Florida SB 700, approved by the governor on May 15, 2025 as Chapter 2025-22, took effect on July 1, 2025. Utah's H.B. 81 (2025) provides that a person may not add fluoride to water in, or water that will be introduced into, a public water system, and that a political subdivision may not enact or enforce an ordinance that requires or permits it. Utah's H.B. 81 took effect on May 7, 2025.
Is fluoride in water a health concern?
NTP's 2024 monograph concluded, with moderate confidence, that drinking water containing more than 1.5 mg/L fluoride is associated with lower IQ in children, and it found insufficient data to determine whether 0.7 mg/L, the level recommended for community water in the United States, has a negative effect on children's IQ. EPA's enforceable limit for fluoride in public drinking water, its maximum contaminant level, is 4.0 mg/L.
Health effects of fluoride in water: what each authority says
More fluoride questions
Frequently asked questions
Why did they stop putting fluoride in water?
Florida's SB 700 (2025) prohibits any additive in a public water system that does not meet the statute's definition of a water quality additive (one used to meet drinking water standards, remove contaminants or improve water quality). Utah's H.B. 81 (2025) provides that a person may not add fluoride to water in, or water that will be introduced into, a public water system, and that a political subdivision may not enact or enforce an ordinance that requires or permits it. Our state-law review records what each law provides, not the reasons given for it.
Do we really need fluoride in our drinking water?
Federal agencies currently address fluoride in different ways. CDC continues to recommend community water fluoridation at the concentration the Public Health Service recommends, describing it as a cornerstone strategy for preventing tooth decay. On October 31, 2025, FDA recommended that ingestible fluoride drug products be limited to children aged 3 and older at high risk for tooth decay. EPA is in an expedited review of fluoride under the Safe Drinking Water Act. As of 2026-10-11, EPA's Fluoride in Drinking Water page does not mention a proposal or proposed rule to change the fluoride MCL.
Which states have banned fluoride in water?
As of 2026-10-11, our state-law review lists Florida and Utah as statewide bans, as the National Conference of State Legislatures does. The National Conference of State Legislatures' fluoride snapshot, updated September 24, 2025, names Utah and Florida as the first states to enact laws prohibiting the addition of fluoride in public water systems. Florida's SB 700 (2025) prohibits any additive in a public water system that does not meet the statute's definition of a water quality additive (one used to meet drinking water standards, remove contaminants or improve water quality). Florida SB 700, approved by the governor on May 15, 2025 as Chapter 2025-22, took effect on July 1, 2025. Utah's H.B. 81 (2025) provides that a person may not add fluoride to water in, or water that will be introduced into, a public water system, and that a political subdivision may not enact or enforce an ordinance that requires or permits it. Utah's H.B. 81 took effect on May 7, 2025.
Sources
- U.S. Department of Health and Human Services Federal Panel on Community Water Fluoridation (Public Health Reports 2015;130(4):318–331). “U.S. Public Health Service Recommendation for Fluoride Concentration in Drinking Water for the Prevention of Dental Caries”. https://pmc.ncbi.nlm.nih.gov/articles/PMC4547570/ (Verified )
- U.S. Environmental Protection Agency. “National Primary Drinking Water Regulations”. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations (Verified )
- World Health Organization. “Guidelines for drinking-water quality: fourth edition incorporating the first and second addenda (2022)”. https://iris.who.int/handle/10665/352532 (Verified )
- National Toxicology Program (NIEHS). “Fluoride Exposure: Neurodevelopment and Cognition”. https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/fluoride (Verified )
- U.S. Environmental Protection Agency. “Secondary Drinking Water Standards: Guidance for Nuisance Chemicals”. https://www.epa.gov/sdwa/secondary-drinking-water-standards-guidance-nuisance-chemicals (Verified )
- Centers for Disease Control and Prevention. “My Water's Fluoride”. https://nccd.cdc.gov/doh_mwf/default/default.aspx (Verified )
- U.S. EPA, 40 CFR 141.153 (via LII). “40 CFR § 141.153 Content of the reports.”. https://www.law.cornell.edu/cfr/text/40/141.153 (Verified )
- Centers for Disease Control and Prevention. “Frequently Asked Questions about Community Water Fluoridation”. https://www.cdc.gov/fluoridation/faq/index.html (Verified )
- NIDCR (NIH). “The Story of Fluoridation”. https://www.nidcr.nih.gov/health-info/fluoride/the-story-of-fluoridation (Verified )
- Centers for Disease Control and Prevention. “2022 Water Fluoridation Statistics”. https://www.cdc.gov/fluoridation/php/statistics/2022-water-fluoridation-statistics.html (Verified )
- U.S. Environmental Protection Agency. “Fluoride in Drinking Water”. https://www.epa.gov/sdwa/fluoride-drinking-water (Verified )
- U.S. Food and Drug Administration. “Ingestible Fluoride Drug Products”. https://www.fda.gov/news-events/public-health-focus/ingestible-fluoride-drug-products (Verified )
- Centers for Disease Control and Prevention. “Community Water Fluoridation Recommendations”. https://www.cdc.gov/fluoridation/about/community-water-fluoridation-recommendations.html (Verified )
- National Conference of State Legislatures. “State of the Tap: Policy Actions on Fluoride in Drinking Water”. https://www.ncsl.org/health/state-of-the-tap-policy-actions-on-fluoride-in-drinking-water (Verified )
- The Florida Senate. “CS/CS/CS/SB 700, Enrolled (2025700er), s. 403.859(8), F.S.”. https://www.flsenate.gov/Session/Bill/2025/700/BillText/er/PDF (Verified )
- The Florida Senate. “CS/CS/CS/SB 700 (2025) bill history”. https://www.flsenate.gov/Session/Bill/2025/700 (Verified )
- Utah State Legislature. “H.B. 81 Fluoride Amendments (Enrolled Copy), Utah Code 19-4-111”. https://le.utah.gov/Session/2025/bills/enrolled/HB0081.pdf (Verified )
Last reviewed by TapWaterData Editorial. How we verify
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"Fluoride in Water: What It Is, Why It's Added, and the Limits". TapWaterData, last reviewed 2026-10-11. https://www.tapwaterdata.com/fluoride