Fluoride
Fond Du Lac Waterworks
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems. Read More.
Fluoride has been promoted as a chemical that reduces dental cavities. Yet it is now well-established that fluoride primarily exerts its protective effects through topical mechanisms, such as sodium fluoride in toothpaste and mouthwash. In contrast, long-term ingestion of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth. EPA's maximum legal limit is set at 4 parts per million (ppm) to prevent skeletal fluorosis, a condition where bones become brittle and more susceptible to fractures, although these effects may occur at lower doses.
Even fluoride levels of 0.7 ppm, the amount of fluoride in drinking water recommended by the U.S. Public Health Service, can result in too much fluoride for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water. The National Toxicology Program is investigating the potential for low doses of fluoride to alter thyroid function and childhood brain development.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.610 ppm | 26 | 26 | 0.394 ppm - 0.835 ppm |
| 2015 | 0.559 ppm | 24 | 24 | 0.362 ppm - 0.740 ppm |
| 2016 | 0.559 ppm | 25 | 25 | 0.391 ppm - 0.732 ppm |
| 2017 | 0.504 ppm | 10 | 10 | 0.420 ppm - 0.550 ppm |
| 2018 | 0.535 ppm | 4 | 4 | 0.480 ppm - 0.580 ppm |
| 2019 | 0.463 ppm | 4 | 4 | 0.372 ppm - 0.560 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EPA Maximum Contaminant
Level (MCL) 4 ppm
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-01-14 | 116375001 | 0.600 ppm |
| 2014-01-14 | 116375001 | 0.540 ppm |
| 2014-02-14 | 119773001 | 0.700 ppm |
| 2014-02-14 | 119773001 | 0.726 ppm |
| 2014-02-18 | 771011 | 0.580 ppm |
| 2014-02-18 | 771008 | 0.630 ppm |
| 2014-03-17 | 123555001 | 0.606 ppm |
| 2014-03-17 | 123555001 | 0.620 ppm |
| 2014-04-18 | 128282001 | 0.788 ppm |
| 2014-04-18 | 128282001 | 0.810 ppm |
| 2014-05-14 | 133080001 | 0.600 ppm |
| 2014-05-14 | 133080001 | 0.622 ppm |
| 2014-06-18 | 140719001 | 0.750 ppm |
| 2014-06-18 | 140719001 | 0.835 ppm |
| 2014-07-16 | 146246001 | 0.594 ppm |
| 2014-07-16 | 146246001 | 0.600 ppm |
| 2014-08-18 | 151847001 | 0.542 ppm |
| 2014-08-18 | 151847001 | 0.660 ppm |
| 2014-09-17 | 158091001 | 0.540 ppm |
| 2014-09-17 | 158091001 | 0.564 ppm |
| 2014-10-14 | 163723001 | 0.500 ppm |
| 2014-10-14 | 163723001 | 0.416 ppm |
| 2014-11-13 | 168444001 | 0.530 ppm |
| 2014-11-13 | 168444001 | 0.607 ppm |
| 2014-12-09 | 171984001 | 0.394 ppm |
| 2014-12-09 | 171984001 | 0.500 ppm |
| 2015-01-14 | 175839001 | 0.583 ppm |
| 2015-01-14 | 175839001 | 0.560 ppm |
| 2015-02-16 | 180140001 | 0.402 ppm |
| 2015-02-16 | 180140001 | 0.440 ppm |
| 2015-03-17 | 184077001 | 0.540 ppm |
| 2015-03-17 | 184077001 | 0.588 ppm |
| 2015-04-16 | 188407001 | 0.590 ppm |
| 2015-04-16 | 188407001 | 0.606 ppm |
| 2015-05-14 | 193825001 | 0.560 ppm |
| 2015-05-14 | 193825001 | 0.596 ppm |
| 2015-06-17 | 200649001 | 0.460 ppm |
| 2015-06-17 | 200649001 | 0.450 ppm |
| 2015-07-24 | 207845001 | 0.540 ppm |
| 2015-07-24 | 207845001 | 0.608 ppm |
| 2015-08-11 | 211294001 | 0.730 ppm |
| 2015-08-11 | 211294001 | 0.659 ppm |
| 2015-09-16 | 218176001 | 0.740 ppm |
| 2015-09-16 | 218176001 | 0.737 ppm |
| 2015-10-16 | 224203001 | 0.660 ppm |
| 2015-10-16 | 224203001 | 0.572 ppm |
| 2015-11-18 | 229547001 | 0.487 ppm |
| 2015-11-18 | 229547001 | 0.440 ppm |
| 2015-12-10 | 232303001 | 0.510 ppm |
| 2015-12-10 | 232303001 | 0.362 ppm |
| 2016-01-14 | 901495 | 0.400 ppm |
| 2016-01-15 | 236025001 | 0.503 ppm |
| 2016-01-15 | 236025001 | 0.570 ppm |
| 2016-02-17 | 240353001 | 0.432 ppm |
| 2016-02-17 | 240353001 | 0.490 ppm |
| 2016-03-16 | 244668001 | 0.474 ppm |
| 2016-03-16 | 244668001 | 0.520 ppm |
| 2016-04-15 | 248974001 | 0.464 ppm |
| 2016-04-15 | 248974001 | 0.520 ppm |
| 2016-05-18 | 255645001 | 0.558 ppm |
| 2016-05-18 | 255645001 | 0.630 ppm |
| 2016-06-13 | 260136001 | 0.569 ppm |
| 2016-06-13 | 260136001 | 0.570 ppm |
| 2016-07-22 | 267903001 | 0.715 ppm |
| 2016-07-22 | 267903001 | 0.620 ppm |
| 2016-08-22 | 273568001 | 0.732 ppm |
| 2016-08-22 | 273568001 | 0.730 ppm |
| 2016-09-15 | 278029001 | 0.717 ppm |
| 2016-09-15 | 278029001 | 0.730 ppm |
| 2016-10-17 | 284832001 | 0.560 ppm |
| 2016-10-17 | 284832001 | 0.391 ppm |
| 2016-11-17 | 289783001 | 0.521 ppm |
| 2016-11-17 | 289783001 | 0.500 ppm |
| 2016-12-01 | 290967001 | 0.530 ppm |
| 2016-12-01 | 290967001 | 0.540 ppm |
| 2017-01-23 | 297536001 | 0.490 ppm |
| 2017-01-23 | 297536001 | 0.533 ppm |
| 2017-02-14 | 973635 | 0.420 ppm |
| 2017-02-15 | 300482001 | 0.550 ppm |
| 2017-02-15 | 300482001 | 0.508 ppm |
| 2017-03-06 | 976160 | 0.540 ppm |
| 2017-03-20 | 305246001 | 0.510 ppm |
| 2017-03-20 | 305246001 | 0.511 ppm |
| 2017-04-21 | 311278001 | 0.510 ppm |
| 2017-04-21 | 311278001 | 0.463 ppm |
| 2018-06-28 | 391726001 | 0.521 ppm |
| 2018-06-28 | 391726001 | 0.580 ppm |
| 2018-07-24 | 397004001 | 0.480 ppm |
| 2018-07-24 | 397004001 | 0.560 ppm |
| 2019-07-18 | 458664001 | 0.372 ppm |
| 2019-07-18 | 458663001 | 0.448 ppm |
| 2019-07-18 | 458664001 | 0.470 ppm |
| 2019-07-18 | 458663001 | 0.560 ppm |