Naturally occurring fluoride is present in the environment. When water passes through and over soil and rock formations containing fluoride, it dissolves these compounds—resulting in the small amounts of soluble fluoride present in virtually all water resources.

What are the health risks from fluoride?
Humans and animals use fluoride in the structure of their bones and teeth. Its effect in reducing the formation of cavities in children is well known. However, in excessive concentrations, ingestion of fluoride can result in bone disease, including pain and tenderness in the bone.

The U.S. Environmental Protection Agency (USEPA) has set a Maximum Contaminant Level for public water systems of 4 milligrams per liter (4 mg/L). Some people who drink water containing fluoride in excess of this level over many years could get bone disease.

The EPA also has set a non-enforceable secondary fluoride standard of 2 mg/L to protect against dental fluorosis, which can cause discoloration of teeth and surface irregularities. Children under nine years of age should not drink water that has more than 2 mg/L of fluoride.

Is my private well at risk?
The presence of fluoride in groundwater depends on the rock and soil types in the area, but concentrations do not usually exceed 10 mg/L. In parts of western Texas, Colorado, and the Dakotas, elevated (greater than 0.5 mg/L) concentrations of fluoride occur naturally in the groundwater. In a sampling nationwide, the U.S. Geological Survey found that 85 percent of wells tested were below the USEPA’s Maximum Contaminant Level.
How do I test for perchlorate in my water?
If you wish to test your water for fluoride, use a certified drinking water testing laboratory, which can provide you with any materials and instructions for taking the sample for analysis.

Your county health department can help you find a list of testing labs. You also can contact your state laboratory certification officer to find a lab near you. Go to the “Water Testing” section of www.WellOwner.org to learn more.

How can I reduce fluoride in my drinking water to acceptable levels?
Two possible options for reducing fluoride in one’s drinking water involve the well construction.

  • A qualified water well system professional may be able to retrofit the well to block off the fluoride-producing water intake zones.
  • A new well that bypasses fluoride-producing zones of groundwater also may be feasible.

If neither of these options is feasible, a qualified water treatment professional can be considered to advise the well owner on appropriate treatment technologies. The three most common ones are:

Reverse osmosis (RO)—Typically, RO is a point-of-use (POU) device installed where the water is used (i.e., under the kitchen sink). It also can be used at the point-of-entry (POE) into the house so that all water is treated.

With POU RO units, a minimum three gallons of wastewater is discharged for every gallon of treated water produced. Since low concentrations of soluble minerals such as calcium, magnesium, iron, and manganese can foul an RO unit, some pretreatment device may be needed.

Maintenance involves replacement of filters and membranes. Filters should be handled carefully and disposed of properly due to potentially high uranium concentrations.

Ion exchange—This involves a physical/chemical process in which water passes through a specialized resin, inducing an exchange of ions removing uranium. Ion exchange is typically used in POE treatment systems.

Maintenance can involve replacement or regeneration of media and cartridges. Spent media and cartridges must be handled carefully and disposed of properly due to potentially high uranium concentrations.

Distillation—Distillation, involving evaporating water and condensing the vapor, requires significant heat energy and cooling capacity. It is generally used in POU systems. Residue disposal must be done according to applicable regulations. Filters should be handled carefully and disposed of properly due to high uranium concentrations.

There are voluntary performance testing programs for water treatment systems, such as those operated by NSF International and the Water Quality Association—although there may not be systems listed that have been evaluated for effectiveness in dealing with uranium. Your water well system contractor can determine whether a system has been independently performance tested.