Fluoride in Tap Water
Fluoride occurs naturally in groundwater and is also added by many utilities at low levels to reduce tooth decay. It is regulated because very high natural levels can affect teeth and bones.
Natural dissolution of fluoride-bearing minerals into groundwater; also intentional community water fluoridation.
- 1Natural mineral deposits
- 2Community water fluoridation
Most affected: Infants fed formula reconstituted with high-fluoride water; people on wells with high natural fluoride.
A result is read with its context
This contaminant is tracked through federal and state compliance monitoring. Private wells, especially in areas with high natural fluoride, are not covered by the federal rule and should be tested directly. PurityMap does not yet publish a per-system measured value for Fluoride; this page is a reference explainer. To learn what is in your own water, check your utility’s Consumer Confidence Report (CCR) or use a certified home test.
- Above reference
- Evidence exceeds a reference level.
- Detected
- This substance was found in the monitoring record. Being present is not the same as being above a reference level, and this signal does not say which.
- Not detected
- Somebody looked and the laboratory reported nothing above its reporting limit. This is a result, and it is not the same as nobody looking.
- Not monitored
- No sampling for this substance has been reported for this system. Nothing is known either way, and an empty row is not a clean one.
24 cities with a published fluoride result
- BoiseID · 2023 · Utility report0.9 mg/LView city →
- OrlandoFL · 2024 · Utility report0.89 mg/LView city →
- Fort WayneIN · 2025 · Utility report0.85 mg/LView city →
- OmahaNE · 2025 · Utility report0.807 mg/LView city →
- LincolnNE · 2025 · Utility report0.76 mg/LView city →
- PhiladelphiaPA · 2025 · Utility report0.75 mg/LView city →
- BostonMA · 2025 · Utility report0.71 mg/LView city →
- Los AngelesCA · 2025 · Utility report0.7 mg/LView city →
- New York CityNY · 2025 · Utility report0.7 mg/LView city →
- ChattanoogaTN · 2025 · Utility report0.69 mg/LView city →
- DurhamNC · 2024 · Utility report0.69 mg/LView city →
- MinneapolisMN · 2024 · Utility report0.67 mg/LView city →
- NormanOK · 2025 · Utility report0.67 mg/LView city →
- CharlotteNC · 2025 · Utility report0.65 mg/LView city →
- Las VegasNV · 2025 · Utility report0.65 mg/LView city →
- DallasTX · 2024 · Utility report0.629 mg/LView city →
- DenverCO · 2025 · Utility report0.61 mg/LView city →
- TampaFL · 2025 · Utility report0.56 mg/LView city →
- AllentownPA · 2025 · Utility report0.55 mg/LView city →
- GreensboroNC · 2025 · Utility report0.55 mg/LView city →
- FriscoTX · 2025 · Utility report0.492 mg/LView city →
- BiloxiMS · 2025 · Utility report0.43 mg/LView city →
- BuffaloNY · 2025 · Utility report0.28 mg/LView city →
- WorcesterMA · 2025 · Utility report0.1 mg/LView city →
Latest published value per city, from Utility report. A system-level result, not a measurement of any single home.
+8 more states.
9 cities with a health-based violation
A violation is a past event with a status, from the federal compliance record (EPA SDWIS, since 2016). It does not describe the water today.
- Lee CountyGeorgiaResolvedView city →
- Sun PrairieWisconsinResolvedView city →
- Brewton WwbAlabamaResolvedView city →
- Lincoln County PwsdMissouriResolvedView city →
- MilfordDelawareResolvedView city →
- AndrewsTexasResolvedView city →
- SandyUtahResolvedView city →
- SaffordArizonaResolvedView city →
- Sonterra MUDTexasResolvedView city →
What can carry a fluoride reduction claim
- Reverse osmosis
Semi-permeable membrane separation removing dissolved minerals, heavy metals, and persistent fluorinated chemicals down to 0.0001 microns.
- Activated alumina / adsorptive media
- Distillation
Boiling does not remove a dissolved chemical compound and can concentrate it. Many pitcher and refrigerator filters carry no verified claim for a compound like this at all.
A finding establishes the need, the need names the capability, the capability requires a verified certification. No product appears before that sequence completes. Filter Finder →
Frequently asked
Answers cite the same records as the page. How PurityMap analyzes water data
Fluoride occurs naturally in groundwater and is also added by many utilities at low levels to reduce tooth decay. It is regulated because very high natural levels can affect teeth and bones.
The enforceable federal limit is 4.0 mg/L (MCL). The health-based goal (MCLG) is 4.0 mg/L. PurityMap reads every measurement against its stated benchmark and never sets its own.
Natural mineral deposits, Community water fluoridation.
At the low levels used for fluoridation, fluoride is associated with reduced tooth decay. Sustained exposure above the enforceable limit is linked to skeletal fluorosis (bone effects); levels above the secondary standard can cause dental fluorosis (tooth mottling) in children. Boiling does not remove fluoride and slightly concentrates it.
Treatment technologies commonly certified to reduce Fluoride include Reverse osmosis, Activated alumina / adsorptive media, Distillation. Match the exact certified claim to your water before buying. Holding a format is not the same as holding the claim.
In PurityMap's published record, 24 cities have a published Fluoride value from utility Consumer Confidence Reports. This is the scope of our record, not a national prevalence estimate.
In the federal compliance record (EPA SDWIS, since 2016), 9 cities in PurityMap's record across 8 states had a water system measure Fluoride above the legal limit, most recently in 2026, including Lee County, GA; Sun Prairie, WI; Brewton Wwb, AL. Each violation is a past event with a published status, not a description of the water today.