Department of
Environmental Quality

Fluoride is a naturally occurring compound derived from fluorine, the 13th most abundant element on Earth. It is found in many rocks and minerals in the soil and enters drinking water as water passes through these soils. Fluoride is present naturally in almost all foods and beverages including water, but levels can vary widely. Very few public water systems in Idaho add fluoride to the drinking water in a process known as fluoridation.

Fluoride Regulation

Fluoride has been shown to prevent tooth decay, but too much fluoride at an early age while the teeth are forming can cause discoloration and pitting of the teeth.  This condition is known as dental fluorosis. Overexposure to fluoride over a lifetime can lead to certain types of bone disease.

How Much Fluoride is Too Much?

EPA has set a Maximum Contaminant Level (MCL) for fluoride of 4.0 mg/L for drinking water for community public water systems. (There is no drinking water standard for fluoride for non-community public water systems.) This means that some people who regularly consume water above this level can experience bone disease. EPA has also set a secondary standard of 2.0 mg/L. Children who regularly consume water above this level may experience dental fluorosis, ranging from white flecks in the mildest forms to brown stains and pitting in the most severe forms.

EPA recommends that children under nine years old not consume water with fluoride concentrations higher than 2.0 mg/L on a regular basis. Your dentist can help you decide how much fluoride you and your family need.

In January 2011, the U.S. Department of Health and Human Services and EPA announced new scientific assessments of fluoride with the intent to review the existing fluoride standard. HHS proposed a recommended standard of 0.7 mg/L for optimal oral health, which is higher than the MCL set by EPA. In response, EPA is initiating a review of fluoride based on new scientific assessments of the health effects of too much fluoride. EPA has not yet decided whether the MCL should be revised, however, and no timeframe has been identified.

Bottled Water & Fluoride

Bottled water is regulated by the U.S. Food and Drug Administration and must meet federal drinking water standards for regulated contaminants. Some bottled water contains natural levels of fluoride from the location that it was collected from.  Some companies add fluoride to their bottled water, which must be indicated on the label. Consumers who choose to purchase bottled water should carefully read the label or contact the bottler to understand what they are buying, for example, the source of water, the method of treatment, and the fluoride level.

Testing for Fluoride

There are several ways to determine the general fluoride concentrations in your area.

• If your water comes from a public water system, ask your water provider.
• If you have a private well, you will need to have your water tested by a qualified lab to determine your fluoride concentrations. Your local public health district can assist you in testing your drinking water. Generally, you will need to follow some simple instructions and take a sample of water to a qualified lab for testing. Fluoride levels in drinking water can fluctuate naturally, so this sample may not represent a constant concentration.
• Finally, the Centers for Disease Control and Prevention (CDC) has a created a website where the general public can access recent fluoride sample results for public water systems.

If you have been advised by a professional that the concentration of fluoride in your drinking water is determined to be too high, it may be necessary to drink only bottled or properly treated water.