Fluoride and Fluoridation

Page Index

Optimal Level and Recommended Control Range

Monitoring

Maximum Contaminant Level (MCL)

Health Effects

Rules

Additional Resources

Fluoridation of drinking water is the addition or adjustment of fluoride to a drinking water supply for the purpose of preventing and controlling tooth decay.

Fluoride is voluntarily added to some drinking water systems as a public health measure for reducing the incidence of cavities among the treated population. The decision to fluoridate a water supply is made by the local municipality, and is not mandated by the Environmental Protection Agency (EPA) or the State of Maine. The U.S. Centers for Disease Control and Prevention (CDC) provides recommendations about the optimal levels of fluoride in drinking water in order to prevent tooth decay.

There are 65 Community water systems in Maine that currently fluoridate, providing drinking water to 133 communities throughout the state to over 520,000 people. Click here for a list of PWS that fluoridate their drinking water.

Fluoride can also be present in water systems that do not fluoridate. Most water supplies contain some naturally occurring fluoride from the erosion of natural deposits in the bedrock. Fluoride can also enter drinking water as a result of impact to groundwater in discharge from fertilizer and aluminum factories from fertilizer.

 

Optimal Level and Recommended Control Range

In Maine, the target level of fluoride for dental benefit in drinking water is 0.7 milligrams per liter (mg/l, or parts-per-million – ppm). The recommended control range is 0.5 to 1.2 mg/l of the optimum level. The recommended control range helps maintain optimal fluoridation.

 

Monitoring

All public water systems that fluoridate must monitor and report the daily fluoride concentration at each application on days in which fluoride is added. Water systems that fluoridate must fill out and submit a Monthly Operating Report (MOR) to record and track the level of fluoride in their water system. These MORs must then be submitted to the Drinking Water Program on a monthly basis.

 

Maximum Contaminant Level (MCL)

The Environmental Protection Agency has established a Maximum Contaminant Level for fluoride in drinking water at 4.0 mg/l.

 

Health Effects of Fluoride

Exposure to excessive consumption of fluoride over a lifetime may lead to increased likelihood of bone fractures in adults, and may result in effects on bone leading to pain and tenderness. Children aged 8 years and younger exposed to excessive amounts of fluoride have an increased chance of developing pits in the tooth enamel, along with a range of cosmetic effects to teeth.

 

Rules

As of February 29, 2012, the Rules Relating to Fluoridation of Public Water Systems were incorporated into 10-144 CMR 231, Section 4(J) of the State of Maine Rules Relating to Drinking Water (PDF).

 

Additional Resources

• Sampling Instructions – Fluoride
• Maine CDC, Oral Health Program – Fluoridation
• Community Water Fluoridation (US CDC)
• Maine Towns with Fluoridation (PDF)

Updated 2/10/2023