Fluorides are compounds that contain the element fluorine. They occur naturally in many water sources and are added in the drinking water treatment process by many public water systems. Fluorides in small amounts are helpful -- amounts between 1.0 and 1.5 milligrams per liter have beneficial effects in reducing tooth decay. Amounts greater than 2.0 parts per million, however, can have harmful effects ranging from the discoloration or pitting of teeth to bone and skeletal damage. Because of these negative effects, EPA has established a Maximum Contaminant Level (MCL) for fluoride of 4.0 milligrams per liter (mg/l), and requires all public water systems to ensure that the safe level is not exceeded.

Does The Fluoride Regulation Apply to Your Community?

Yes, all community public water systems must test for fluoride at every entry point to the distribution system after treatment. Tests must be made every three years for ground water sources and annually for surface water sources.

Actions Your Community Should Be Taking

You are responsible for keeping fluoride levels in your public water source at or below the fluoride MCL. If your fluoride levels are below this MCL, you are in compliance with EPA regulation. However, if your tests indicate fluoride levels between 2.0 and 4.0 mg/l, you should still check with your state agency and/or an engineer to see if any changes in operations can be made to lower the fluoride level even further.

Fluoride levels between 2.0 and 4.0 mg/l do not exceed the MCL, and immediate corrective action is not required, but planning should be undertaken to reduce levels below 2.0 mg/l. If your fluoride levels are between 2.0 and 4.0 mg/l, your state agency may require more frequent sampling to monitor your fluoride levels, and you will also be required to inform the public that your water has fluoride levels between 2.0 and 4.0 mg/l.

If your tests indicate fluoride levels above 4.0 mg/l, you are in violation of the MCL. Beginning the first quarter after the violation, you must begin quarterly monitoring, and you must follow all requirements for notifying the public of the violation. In addition, you should work with your state agency and/or an engineer to determine the best way to reduce the level of fluoride in your water supply. Solutions to fluoride violations for very small water systems usually involve finding and using a new water source, or mixing existing sources to reduce the fluoride level.

Another option is to remove fluoride through treatment, but this option can be cost?prohibitive for very small systems. In order to continue to use the water supply while solutions to the MCL violation are being explored, you should request an exemption from the appropriate state agency. Seek help through other resource agencies for help in finding financial resources, if needed, to make those water system changes.

Additional Information

The fluoride requirements are published in Title 40 Code of Federal Regulations, Parts 141.11, 141.23, 141.62, 143.3.

Contact the National Technical Information Service at 1/800/553-6847 for guidance documents pertaining to fluoride.

Contact your local dentist or state dental association for information on the beneficial effects of fluoride in your drinking water.

For further information on the federal requirements, contact the EPA Safe Drinking Water Hotline at 1/800/426-4791.

(See Resource Section for drinking water contacts)