Fluoride was first added to a city’s water supply in 1945 in Grand Rapids, Michigan. As a result, the rate of cavities in school children fell by nearly 60 percent. Water fluoridation then became widespread as a means to improve communities’ oral health, and by 2022 about 63 percent of people in the United States received fluoridated water. While fluoride helps prevent cavities, community water fluoridation is now under renewed debate over the possible effects of too much fluoride. Below you will learn about the benefits and risks of fluoride, how to find out if your water is fluoridated, and how to remove fluoride from your water if you choose to do so.
Quick answer: The most reliable ways to remove fluoride from water are reverse osmosis, which removes about 85 to 95 percent, and distillation, which removes nearly all of it. Activated alumina and bone char filters also work but need slow flow and regular media changes. Boiling, standard carbon filters, most pitchers and water softeners don’t remove fluoride.
What is fluoride?Fluoride is a natural form of the element fluorine, and it’s a mineral found in teeth, bones, water, rocks, and soil. Fluoride is commonly used in dentistry to strengthen enamel (the outer layer of your teeth) and to prevent cavities.
Why is fluoride added to water?Fluoride is added to water because it is effective in preventing cavities and in helping to improve and maintain oral health. Almost all water contains naturally occurring fluoride, but usually at levels too low to prevent tooth decay, so many municipalities adjust the fluoride concentration in the water supply to about 0.7 milligrams per liter. 0.7 mg/L is the optimal level of fluoride in drinking water to prevent tooth decay in both children and adults, according to the Centers for Disease Control (CDC).
Community water fluoridation began after scientists found that people who lived in areas where fluoride was naturally prevalent in water had fewer cavities. When fluoride was purposefully added to the water supply in Grand Rapids, Michigan in 1945 it was an experiment of sorts, but proved so successful in improving the community’s oral health, that water fluoridation became the norm shortly after.
Fluoridation policy is changing. In 2025, Utah and Florida became the first states to ban adding fluoride to public water, other states have considered similar bills, and the EPA has started a new review of its fluoride standard. Many communities still fluoridate, so check with your local water supplier to see what’s in your tap water.
4.0 mg/L and lower are safe levels of fluoride in drinking water, according to the Environmental Protection Agency (EPA). The EPA set 4.0 mg/L as the Maximum Contaminant Level for fluoride in drinking water provided by public water systems. The EPA also has a non-enforceable secondary standard of 2.0 mg/L to protect against tooth staining. The recommended amount of fluoride for community water has been much lower, at 0.7 mg/L. Levels higher than 0.7 mg/L increase the risk of dental fluorosis in children (a cosmetic condition characterized by stained or discolored teeth).
What are the side effects of fluoride in water?The side effects of fluoride in water can be both positive and negative. However, keep in mind that adverse health effects are highly unlikely to occur because of community water fluoridation, as the amount of fluoride in public water systems is too low. The CDC has long stated that community water fluoridation is safe and effective, with dental fluorosis as the main side effect. Some researchers and officials have questioned this, and federal agencies are reviewing the science.
Although, certain areas of the world, including large parts of Asia and Africa, have large geologic deposits of fluoride that can contaminate water supplies. Also, although rare, a person can be exposed to dangerous amounts of fluoride through industrial chemicals. Instances such as these can lead to excessive fluoride intake and may be linked to the health risks listed below.
Benefits of fluoride in water:
- Fewer and less severe cavities
- Rebuilds weakened tooth enamel
- Reverses early signs of tooth decay
- Prevents the growth of harmful oral bacteria
- Less need for fillings and tooth extractions
Risks of fluoride in water:
- Dental fluorosis: A cosmetic condition characterized by stained, discolored teeth because of excessive fluoride exposure in children and infants.
- Skeletal fluorosis: When high levels of fluoride accumulate in bones, it may result in joint pain, muscle impairment, and stiffness.
- Hypothyroidism: Under-active thyroid that may cause fatigue, increased sensitivity to cold, dry skin, and weight gain.
- Lower IQ in children: A 2024 National Toxicology Program review linked fluoride levels above 1.5 mg/L, about twice the U.S. recommended level, to lower IQ in children. Most of the studies were done outside the U.S.
Fluoride can be removed from drinking water through reverse osmosis, distillation, activated alumina filters, and bone char carbon filters.
| Method | Removes fluoride? | Good to know |
|---|---|---|
| Reverse osmosis | Yes, about 85–95% | Most popular option for drinking water; look for NSF/ANSI 58 |
| Distillation | Yes, nearly all | Slow (hours per gallon) and uses electricity |
| Activated alumina | Yes | Works best at low pH and slow flow |
| Bone char | Yes | Needs regular replacement; made from animal bones |
| Boiling | No | Actually concentrates fluoride as water evaporates |
| Standard carbon filters and most pitchers | No | Great for chlorine and taste, not fluoride |
| Water softeners | No | Remove hardness minerals, not fluoride |
Reverse osmosis
Reverse osmosis uses pressure to push unfiltered water through a semipermeable membrane. Water molecules are small enough to pass through the membrane’s tiny pores, but most contaminants, including 85 to 95 percent of fluoride, are rejected and sent to the drain. Look for systems certified to NSF/ANSI 58 for fluoride reduction.
Learn more: What is a Reverse Osmosis System and How Does It Work? | Our recommended reverse osmosis systems
Distillation
Distillation is a water treatment method that mimics how water is purified in nature: through evaporation in the atmosphere. Water distillers convert water into steam, eliminating fluoride and other contaminants because they cannot take on a gaseous form as water can. Once the steam cools back into liquid, nearly all of the fluoride is left behind.
Learn more: What is a Water Distiller and How Does It Work? | What is Distilled Water and Is It Safe to Drink?
Activated alumina filters
Activated alumina is a porous, solid form of aluminum oxide. When water passes through an activated alumina filter, fluoride and other contaminants are adsorbed by activated alumina granules, allowing clean water to flow to the other side. However, activated alumina filters only work in water with a pH of less than 8.5 and are most effective at removing fluoride from water with a pH between 5 and 6. Additionally, they require a lot of contact time to be effective, so water flow rates have to be very slow.
Bone char carbon filters
Bone char carbon filters are one of the oldest methods to remove fluoride from water. Standard activated carbon filters do not remove fluoride, but bone char is different. It’s made by heating animal bones to very high temperatures, which leaves a material made mostly of calcium phosphate with some carbon. The calcium phosphate attracts and holds fluoride as water passes through. Bone char filters can even remove heavy metals, including lead, and chlorine.
Learn more: Activated Carbon Filters 101 | How to Remove Lead from Water
Does boiling water remove fluoride?No, boiling water does not remove fluoride. Since some water evaporates during the boiling process, fluoride concentrations will instead increase.
Do Brita filters remove fluoride?No, Brita filters do not remove fluoride. Standard Brita filters use carbon and ion exchange resin, which don’t lower fluoride levels. A few specialty pitchers are tested for fluoride reduction.
Learn more: The best water filter pitchers
Is your water fluoridated?You can find out if your water is fluoridated by checking with your municipal water supplier or through the CDC’s online My Water's Fluoride tool. Not every city in the U.S. fluoridates its drinking water. The decision is usually made locally, though some states now ban it. Both your municipal water supplier and the CDC’s online tool can tell you whether your water is fluoridated, and if yes, how much fluoride is added.
Is fluoride in bottled water?Fluoride may be in bottled water. It depends on the brand and the original water source of the bottled water you choose. Fluoride may be naturally present in the original water source or may be added by a municipality. Many bottled waters are filled from municipal water supplies, so if the municipality fluoridates its water, the bottled water may be fluoridated too. However, fluoride will only appear on the label if it was added during the bottling process, so we recommend checking with the brand you like to find out if it contains fluoride.
Does a water softener remove fluoride?No. Water softeners swap calcium and magnesium for sodium or potassium. They don’t remove fluoride. If you want soft water and less fluoride, pair a softener with a reverse osmosis system for your drinking water.
Do refrigerator filters remove fluoride?Most don’t. Refrigerator filters are usually carbon filters, which improve taste and reduce chlorine but not fluoride. Check the filter’s performance data sheet to see what it’s certified to reduce.
If you have any further questions about water fluoridation or how to remove fluoride from your water, please don’t hesitate to contact us.
