Inorganic chemicals
Fluoride in U.S. tap water
1,249 public water systems across 44 U.S. states report Fluoride in their annual Consumer Confidence Report. 7 sit at or above the federal limit.
What it is
A mineral often added to drinking water to help prevent tooth decay.
Why it's regulated
Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.
At or above the federal limit (7)
| Water system | Measured | vs. limit |
|---|---|---|
| Pittsburgh, PA 2024 annual report | 101 mg/L | 25.3× the limit |
| Pixley Public Util Dist — Pixley, Ca, CA 2023 annual report | 0.11–16 mg/L | 4.0× the limit |
| Mcfarland, City of — Mcfarland, Ca, CA 2023 annual report | 0.2–10 mg/L | 2.5× the limit |
| Yonkers, NY 2024 annual report | 5 mg/L | 1.3× the limit |
| Frisco, TX 2024 annual report | 4 mg/L | 1.0× the limit |
| San Bernardino Valley Wd — San Bernardino, Ca, CA 2023 annual report | 4 mg/L | 1.0× the limit |
| St Petersburg, FL 2024 annual report | 4 mg/L | 1.0× the limit |
Approaching the limit (5)
| Water system | Measured | vs. limit |
|---|---|---|
| Goodyear, AZ 2024 annual report | 3.46 mg/L | 0.9× the limit |
| Kinneloa Irrigation Dist. — Pasadena, Ca, CA 2021 annual report | 0.86–3.4 mg/L | 0.8× the limit |
| San Antonio, TX 2023 annual report | 0.15–3.31 mg/L | 0.8× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2023 annual report | 3.3 mg/L | 0.8× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2022 annual report | 3.2 mg/L | 0.8× the limit |
Within the federal limit (1236)
Showing 50 of 1236. The full list is in the JSON API.
Frequently asked
+What is Fluoride?
A mineral often added to drinking water to help prevent tooth decay. Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.
+What is the federal limit for Fluoride in drinking water?
The federal MCL for Fluoride is 4 mg/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have Fluoride over the federal limit?
7 of the 1249 public water systems on The Water Map report Fluoride at or above its federal limit, spanning 44 U.S. states. The full list is on this page.
+How can I check if Fluoride is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Fluoride.