Fluoride
A mineral added to most US water systems to prevent tooth decay. Also occurs naturally in some groundwater.
Source
Intentionally added during water treatment. Also from natural deposits and industrial discharge.
Health Risk
At recommended levels (0.7 ppm), strengthens teeth. Excessive levels above 4 ppm can cause bone disease and mottled teeth.
Filter Tip
Reverse osmosis, activated alumina, and bone char filters can reduce fluoride. Standard carbon filters do not remove fluoride.
Fluoride is unique among drinking water contaminants because it is intentionally added to most US public water systems to prevent tooth decay. About 73% of Americans on public water systems receive fluoridated water at a target level of 0.7 parts per million (ppm).
The EPA's Maximum Contaminant Level for fluoride is 4 ppm, and the secondary (cosmetic) limit is 2 ppm. Natural fluoride levels in groundwater can sometimes exceed these limits.
Benefits and Risks of Fluoride
Benefits (at 0.7 ppm):
- Reduces tooth decay by 25% in children and adults
- Strengthens tooth enamel
- Considered one of the top 10 public health achievements of the 20th century by the CDC
Risks (at excessive levels):
- Dental fluorosis — white spots or mottling on teeth (cosmetic, above 2 ppm)
- Skeletal fluorosis — bone pain and damage (above 4 ppm, with long-term exposure)
- Some studies suggest possible links to thyroid effects and neurodevelopmental concerns at high levels
How to Remove Fluoride
If you prefer to reduce fluoride in your drinking water:
- Reverse Osmosis: Removes 90-95% of fluoride — the most effective method
- Activated Alumina: Designed specifically for fluoride removal
- Bone Char Carbon: A specialized carbon filter effective for fluoride
- Distillation: Effective but slow
Important: Standard activated carbon filters (Brita, PUR, etc.) do NOT remove fluoride.
Fluoride Levels in US Cities
Based on verified municipal water quality reports (Consumer Confidence Reports) from 22 cities.
Detected Within Limits (22)
Frequently Asked Questions
Is fluoride in water safe?
At the recommended level of 0.7 ppm, major health organizations (CDC, WHO, ADA) consider fluoride in water safe and beneficial for dental health. The EPA MCL of 4 ppm is the enforceable limit. Natural fluoride above 2 ppm may cause cosmetic dental fluorosis.
Does a Brita filter remove fluoride?
No. Standard activated carbon filters including Brita, PUR, and most pitcher filters do not remove fluoride. To remove fluoride, you need a reverse osmosis system, activated alumina filter, or bone char filter.
Which cities have the most fluoride?
Most US cities add fluoride at 0.7 ppm. Some areas with naturally high fluoride include parts of the Southwest, the Great Plains, and areas with volcanic geology. Check your city page on TapWater.org for specific levels.
Related Contaminants
Nitrate
A compound found naturally in soil and water, but elevated levels usually indicate contamination from fertilizers or sewage.
Chloramine
A disinfectant made from chlorine and ammonia, used as an alternative to chlorine. Lasts longer in the distribution system.
Lead
A toxic heavy metal that typically enters drinking water through corroding pipes, faucets, and solder — not from the water source itself.