Fluoride Action Network

CDC: Fluoride in Private Well Water

Source: National Center for Chronic Disease Prevention and Health Promotion | Division of Oral Health
Posted on March 11th, 2021

Online as of March 11, 2021


My home gets its water from a private well. What do I need to know about fluoride and groundwater from a well?

Fluoride is present in virtually all waters and it is important to know the fluoride content of your water, particularly if you have children. The fluoride content of your well water can be determined only through laboratory analysis. Your local public health department can tell you where to have your home well water tested. Additional information on testing the water quality of private residential wells can be found on the U.S. Environmental Protection Agency Web siteexternal icon.

What should I do if my well water has less fluoride than is recommended for the prevention of tooth decay?

Drinking water needs to contain 0.7 mg/L (milligrams per liter) of fluoride to reliably provide fluoride’s oral health benefits. If your drinking water contains less than 0.7 mg/L, your child’s dentist or pediatrician should evaluate whether your child could benefit from daily fluoride supplements. Their recommendation will depend on your child’s risk of developing tooth decay and their exposure to other sources of fluoride, such as fluoride toothpaste and drinking water at school or daycare. It is not currently feasible to fluoridate water for a single household.

What should I do if my well’s water has more fluoride than is recommended for preventing tooth decay?

Water sources in certain regions of the United States contain naturally occurring fluoride at levels above that recommended by the US Public Health Service for the prevention of tooth decay. The US Environmental Protection Agency (EPA) recommends that drinking water contain no more than 2.0 mg/L of fluoride. This is a non-enforceable guideline and is intended to help children avoid dental fluorosis, a usually cosmetic discoloration of tooth enamel that can result from excessive fluoride consumption while teeth are developing in the gums. If your drinking water has a fluoride content of 2.0 mg/L or higher, EPA recommends that children 8 years and younger be provided with alternative sources of drinking water to guard against dental fluorosis.

What should I do if my well water has a fluoride content of 4 mg/L or higher?

Potable water sources rarely have a fluoride content of 4 mg/L or higher. If laboratory testing indicates that your water has a fluoride content of 4mg/L or higher, you should have your well tested again to confirm the accuracy of the findings. Collect at least four samples over four weeks (one sample each week) and compare the results. If all samples show levels greater than 4 mg/L, you should consider installing a filter that can remove fluoride from your water or using other water for drinking and cooking. Bathing or washing dishes with water containing high levels of fluoride is safe because fluoride in water does not pass through the skin.


Page last reviewed: September 17, 2019