CDC recommends fluoride to prevent cavities, and it helps to know how much fluoride is in your main drinking water — that can guide decisions about other fluoride products, or about cutting back.
Where fluoride comes from
Fluoride is an ion of fluorine, the 13th most common element in the earth's crust. It is found naturally in almost all soil and water and in many rocks, and enters the environment when water dissolves fluoride-bearing rock or soil. Volcanic emissions and human processes release it too.
Why it is added to water
Fluoride combines with the outer enamel of teeth, making them stronger and more resistant to decay. Almost all water has some natural fluoride, but usually too little to prevent cavities, so many communities add a small amount to the supply.
Who decides? Not CDC: it does not mandate fluoridation, and the U.S. Public Health Service's recommended level is not enforceable. State and local governments decide — often voters themselves. Some states require water systems above a certain size to fluoridate, and in some places natural fluoride is already at a level proven to prevent cavities.
Toothpaste too? Yes — the two work together. Fluoridated water keeps a low level in the mouth all day; fluoride toothpaste gives a much higher dose at key times, such as bedtime. Both strengthen enamel and slow the bacteria that cause cavities, and together they protect better than either alone.
Checking your water
- Tap water: ask your local water provider.
- Well water: only a laboratory test can tell; your local health department can say where to get one.
- Bottled water: some has fluoride — from a fluoridated public supply, or naturally from springs or aquifers — and some doesn't. Water labeled de-ionized, purified, demineralized or distilled has none or only traces, unless fluoride is listed as an added ingredient. Ask the maker about a particular brand.
The numbers that matter
| Fluoride in drinking water | What it means |
|---|---|
| Below 0.7 mg/L | not enough to reliably prevent cavities — talk to your dentist, or your child's pediatrician, about other fluoride products |
| 0.7 mg/L | the level needed to reliably prevent cavities |
| Above 2.0 mg/L | over the Environmental Protection Agency's non-enforceable guideline, meant to protect children from dental fluorosis. Water systems must notify customers, and EPA advises another water source for children 8 and under. Fewer than 1% of the U.S. population has water this high |
| 4.0 mg/L or more | contact your health department for specific steps; consider a filter that removes fluoride from water for drinking and cooking |
Dental fluorosis develops only in children, while teeth are still forming under the gums — up to about age 8. Fluoride is not absorbed through the skin, so water high in fluoride is still fine for cleaning and bathing. Pregnant women and parents in high-fluoride areas can use low-fluoride bottled water, for example for infant formula.
If you drink mostly bottled water
Drinking enough water matters: it prevents dehydration, which can cloud thinking, change mood, overheat the body, and lead to constipation and kidney stones. But if most of it is bottled, you may be getting too little fluoride to protect your teeth — tell your dental provider, who can help you find the best way to prevent cavities.
Infant formula
- Powdered or liquid-concentrate formula mixed with fluoridated water may raise the chance of mild dental fluorosis if it is the baby's main food.
- Ready-to-feed formula contains little fluoride and does not cause fluorosis.
- To lower the risk, parents can use low-fluoride bottled water — labeled de-ionized, purified, demineralized or distilled — some of the time for mixing. Some bottled waters are sold specifically for infants and formula. The Food and Drug Administration has more on bottled water and infant formula.
Sources
Based on "Community Water Fluoridation Frequently Asked Questions," Centers for Disease Control and Prevention; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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