What Fluoride is, and why it's regulated
What the EPA limit means
4000 µg/L
Maximum Contaminant Level — the enforceable ceiling a supplier must stay under.
4000 µg/L
Health goal (MCLG) — the level with no known health effect. It is a goal, not a legal limit, and is often zero for carcinogens.
SYR4
Where these measurements come from. Hover the tag for the EPA programme and years.
Where Fluoride was found
The water suppliers reporting the highest levels, worst first. For lead and copper that is the 90th-percentile result the action level is written against; for Six-Year Review data, the 95th percentile of each system's samples.
| Supplier | City | State | Level vs EPA limit |
|---|---|---|---|
| St. Joe Water Department | St. Joe | IN | 270110 µg/L 6753% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Curtiss Waterworks | Curtiss | WI | 151270 µg/L 3782% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Keshena | Keshena | WI | 51311.5 µg/L 1283% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Dennehotso Ntua | Dennehotso | AZ | 34696.5 µg/L 867% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Garden Valley Ranchettes Homeowners | Garden Valley | ID | 18900 µg/L 472% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Alpine Acres Water District | Patterson | NY | 12000 µg/L 300% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Cyrus | Cyrus | MN | 11550 µg/L 289% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Carthage Water Department | Carthage | IN | 10590 µg/L 265% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Csa 70 w-4 Pioneertown | San Bernardino | CA | 9460 µg/L 237% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Elk Ridge Town | Orem | UT | 9460 µg/L 237% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Us Army Fort Irwin | Fort Irwin | CA | 9000 µg/L 225% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Ute Heights Community Ws | Nathrop | CO | 8925 µg/L 223% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Chuckawalla Valley State Prison | Blythe | CA | 8900 µg/L 223% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Shuler Point Water System | Clifton | TX | 8767.5 µg/L 219% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Jubilee Mwc | Lucerne Valley | CA | 8575 µg/L 214% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Juniper Riviera Cwd | — | CA | 8100 µg/L 203% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Asoleado Mwc | Carmel Valley | CA | 7740 µg/L 194% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Csa 51 | Desert Center | CA | 7675 µg/L 192% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| City of Wellman | Wellman | TX | 7621.5 µg/L 191% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Qvwd-West & East Combined Water System | Tehachapi | CA | 7470 µg/L 187% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Jbsa Randolph | San Antonio | TX | 7308 µg/L 183% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Spv Water Company | Valencia | CA | 7160 µg/L 179% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| Meadow Estates Mutual | Boonville | CA | 6920 µg/L 173% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| City of Opdyke West | Levelland | TX | 6847.5 µg/L 171% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
| San Simon Dwid | San Simon | AZ | 6410 µg/L 160% of the EPA limit, at the 95th percentile of samples — 4000 µg/L |
Frequently asked questions about Fluoride
What is Fluoride in drinking water?
Fluoride occurs naturally and is added to prevent tooth decay; too much causes dental and skeletal fluorosis.
What is the EPA limit for Fluoride?
The EPA's Maximum Contaminant Level for Fluoride is 4000 µg/L, and its health goal (MCLG) is 4000 µg/L. A result above the limit means the supplier must act; the goal is the level at which no health effects are expected.
How common is Fluoride in US tap water?
Of the 33,849 water suppliers with results on file, 25,909 detected Fluoride — 76.5% of those tested.