Fluoride in drinking water

Most water already contains fluoride. Some places have more fluoride in their water than others. When the fluoride level is too low to prevent tooth problems, towns and cities can choose to add fluoride. This process is called “water fluoridation.” The best level of fluoride to help your child’s teeth is 0.7 milligrams of fluoride per liter of water (mg/L). That’s about three drops of water in a 55-gallon barrel. In Indiana, most drinking water has fluoride levels slightly below the recommended amount. Each community decides whether it wants to add fluoride to its drinking water.

History of fluoride added to water

Communities started adding fluoride to drinking water in 1945. Before then, tooth decay was very common. Many people did not see dentists or have dental care. Doctors and scientists noticed that people who lived in places with higher levels of fluoride in their water had a lower rate of decay.

Scientists realized that adding fluoride to drinking water was an easy way to protect many people’s teeth. The U.S. Centers for Disease Control and Prevention (CDC) calls water fluoridation one of the top 10 public health successes. The CDC says fluoride in water helped reduce tooth decay in children by up to 70%. It also reduced tooth loss in adults by up to 60%.

Fluoride in bottled water and water filters

Many people drink only bottled water. Some brands of bottled water include fluoride. But most brands do not have enough fluoride to help your child’s teeth. Tell your child’s dentist if you drink mainly bottled water. This can help the dentist understand how much fluoride your child is getting.

People also use filters to clean tap water and make it taste better. Some filters remove fluoride from the water, and some do not. There are two main types of at-home water filters:

Point-of-use filters are the most common. These include water pitchers and filters that attach to your faucet. Most of these filters do not remove fluoride from tap water. The American Dental Association (ADA) approves filters that do not remove fluoride from tap water.

Point-of-entry filters clean all the water entering your house. Reverse osmosis systems are the most common. These filters can remove all fluoride from tap water. But these filters need to be taken care of regularly to work correctly.

Tell your child’s dentist if you use a water filter at home. This is more information to help your dentist understand how much fluoride your child is getting.

If you are worried about your water quality, the Indiana Department of Health offers tests for your water.

Questions about fluoride

• Is fluoride toxic? Fluoride is safe in small amounts i.e. fluoridated toothpaste. It can be harmful if your child swallows too much fluoride and young children should always be supervised when brushing their teeth.
• What is dental fluorosis? This describes white spots on teeth. Dental fluorosis can happen when a child has too much fluoride while their adult teeth are growing.
• Does fluoride in water cause cancer? The American Cancer Society says there is no strong evidence that fluoride in water causes cancer.
• Can fluoride in water lower a child’s IQ? Some studies in other countries have suggested a possible link between fluoride and IQ. These studies were done in places with much higher fluoride levels than the levels in the United States. Experts agree there isn’t enough evidence that the level of fluoride currently recommended, harms children’s IQ.
• What happens when communities stop adding fluoride to public drinking water? Cities like Buffalo, Calgary and Juneau removed fluoride from their water. Later, people in those cities had more dental problems or more expensive dental care.

Want to learn more?

You can visit the Indiana Health Department to learn more about water fluoridation. For more information about fluoride in drinking water, visit:

• Indiana Department of Health's water programs
• My Water's Fluoride (CDC)
• The Campaign for Dental Health (American Academy of Pediatrics)
• MouthHealthy (ADA)