Fluoride in Drinking Water

EPA Limit: 4 mg/L

The EPA MCL for fluoride is 4 mg/L, with a secondary (cosmetic) standard of 2 mg/L. Fluoride violations typically occur in systems using groundwater in areas with naturally high fluoride geology.

Where Does Fluoride Come From?

Fluoride occurs naturally in groundwater in many regions and is also added to many public water supplies at lower levels (around 0.7 mg/L) to prevent tooth decay. Violations occur when natural fluoride levels exceed the MCL, which is more common in arid regions with certain geological formations.

Health Risks

At levels above the MCL (4 mg/L), fluoride can cause skeletal fluorosis, leading to pain and tenderness of bones and joints. At levels above 2 mg/L (the secondary standard), it can cause dental fluorosis, particularly in developing teeth of young children.

What Should I Do?

Reverse osmosis, activated alumina, and distillation filters effectively reduce fluoride levels. Standard carbon filters do not remove fluoride. If your water naturally exceeds 2 mg/L, use alternative water sources for children under 8.