Fluoride
Ellsworth 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 | 0.267 ppm | 27 | 27 | 0.0960 ppm - 0.580 ppm |
| 2015 | 0.675 ppm | 24 | 24 | 0.360 ppm - 1.27 ppm |
| 2016 | 0.586 ppm | 26 | 26 | 0.320 ppm - 0.888 ppm |
| 2017 | 0.596 ppm | 27 | 27 | 0.0900 ppm - 0.830 ppm |
| 2018 | 0.649 ppm | 24 | 24 | 0.155 ppm - 1.18 ppm |
| 2019 | 0.788 ppm | 24 | 24 | 0.554 ppm - 1.36 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 |
|---|---|---|
| 2014-01-13 | 116516001 | 0.1000 ppm |
| 2014-01-13 | 116516001 | 0.360 ppm |
| 2014-02-07 | 119660001 | 0.115 ppm |
| 2014-02-07 | 119660001 | 0.230 ppm |
| 2014-03-20 | 124442001 | 0.185 ppm |
| 2014-03-20 | 124442001 | 0.300 ppm |
| 2014-04-08 | 127170001 | 0.125 ppm |
| 2014-04-08 | 127170001 | 0.230 ppm |
| 2014-05-22 | 135582001 | 0.119 ppm |
| 2014-05-22 | 135582001 | 0.390 ppm |
| 2014-06-17 | 140546001 | 0.117 ppm |
| 2014-06-17 | 140546001 | 0.250 ppm |
| 2014-07-10 | 144736001 | 0.1000 ppm |
| 2014-07-10 | 144736001 | 0.108 ppm |
| 2014-08-07 | 809092 | 0.140 ppm |
| 2014-08-22 | 153863001 | 0.110 ppm |
| 2014-08-22 | 153863001 | 0.129 ppm |
| 2014-08-27 | 813678 | 0.0960 ppm |
| 2014-08-27 | 813675 | 0.0990 ppm |
| 2014-09-22 | 159569001 | 0.411 ppm |
| 2014-09-22 | 159569001 | 0.440 ppm |
| 2014-10-22 | 165413001 | 0.430 ppm |
| 2014-10-22 | 165413001 | 0.475 ppm |
| 2014-11-19 | 169700001 | 0.483 ppm |
| 2014-11-19 | 169700001 | 0.580 ppm |
| 2014-12-22 | 173803001 | 0.527 ppm |
| 2014-12-22 | 173803001 | 0.550 ppm |
| 2015-01-15 | 176784001 | 0.497 ppm |
| 2015-01-15 | 176784001 | 0.640 ppm |
| 2015-02-04 | 178603001 | 0.392 ppm |
| 2015-02-04 | 178603001 | 0.470 ppm |
| 2015-03-03 | 182251001 | 0.537 ppm |
| 2015-03-03 | 182251001 | 0.570 ppm |
| 2015-04-14 | 188456001 | 0.509 ppm |
| 2015-04-14 | 188456001 | 0.750 ppm |
| 2015-05-05 | 192194001 | 0.720 ppm |
| 2015-05-05 | 192194001 | 0.795 ppm |
| 2015-06-02 | 197720001 | 0.440 ppm |
| 2015-06-02 | 197720001 | 0.663 ppm |
| 2015-07-07 | 204749001 | 0.360 ppm |
| 2015-07-07 | 204749001 | 0.472 ppm |
| 2015-08-18 | 212753001 | 0.620 ppm |
| 2015-08-18 | 212753001 | 0.893 ppm |
| 2015-09-09 | 216784001 | 0.600 ppm |
| 2015-09-09 | 216784001 | 0.868 ppm |
| 2015-10-15 | 224204001 | 1.03 ppm |
| 2015-10-15 | 224204001 | 1.27 ppm |
| 2015-11-05 | 227296001 | 0.895 ppm |
| 2015-11-05 | 227296001 | 0.940 ppm |
| 2015-12-09 | 233244001 | 0.580 ppm |
| 2015-12-09 | 233244001 | 0.700 ppm |
| 2016-01-14 | 236026001 | 0.570 ppm |
| 2016-01-14 | 236026001 | 0.634 ppm |
| 2016-02-02 | 238383001 | 0.490 ppm |
| 2016-02-02 | 238383001 | 0.525 ppm |
| 2016-03-01 | 243291001 | 0.538 ppm |
| 2016-03-01 | 243291001 | 0.640 ppm |
| 2016-04-19 | 250209001 | 0.510 ppm |
| 2016-04-19 | 250209001 | 0.610 ppm |
| 2016-05-05 | 252867001 | 0.541 ppm |
| 2016-05-05 | 252867001 | 0.650 ppm |
| 2016-06-09 | 259612001 | 0.490 ppm |
| 2016-06-09 | 259612001 | 0.871 ppm |
| 2016-06-22 | 262566001 | 0.590 ppm |
| 2016-06-22 | 262566001 | 0.888 ppm |
| 2016-07-20 | 267871001 | 0.320 ppm |
| 2016-07-20 | 267871001 | 0.498 ppm |
| 2016-08-05 | 270521001 | 0.500 ppm |
| 2016-08-05 | 270521001 | 0.560 ppm |
| 2016-09-06 | 276298001 | 0.655 ppm |
| 2016-09-06 | 276298001 | 0.660 ppm |
| 2016-10-04 | 282531001 | 0.580 ppm |
| 2016-10-04 | 282531001 | 0.635 ppm |
| 2016-11-15 | 289643001 | 0.700 ppm |
| 2016-11-15 | 289643001 | 0.718 ppm |
| 2016-12-01 | 290969001 | 0.412 ppm |
| 2016-12-01 | 290969001 | 0.460 ppm |
| 2017-01-05 | 295738001 | 0.496 ppm |
| 2017-01-05 | 295738001 | 0.570 ppm |
| 2017-02-02 | 299426001 | 0.650 ppm |
| 2017-02-02 | 299426001 | 0.683 ppm |
| 2017-03-07 | 303439001 | 0.678 ppm |
| 2017-03-07 | 303439001 | 0.700 ppm |
| 2017-03-14 | 977576 | 0.140 ppm |
| 2017-04-04 | 308396001 | 0.630 ppm |
| 2017-04-04 | 308396001 | 0.685 ppm |
| 2017-05-01 | 313465001 | 0.492 ppm |
| 2017-05-01 | 313465001 | 0.500 ppm |
| 2017-05-30 | 994073 | 0.0900 ppm |
| 2017-05-30 | 994070 | 0.0940 ppm |
| 2017-06-06 | 320532001 | 0.689 ppm |
| 2017-06-06 | 320532001 | 0.770 ppm |
| 2017-07-10 | 327941001 | 0.390 ppm |
| 2017-07-10 | 327941001 | 0.601 ppm |
| 2017-08-04 | 333409001 | 0.714 ppm |
| 2017-08-04 | 333409001 | 0.750 ppm |
| 2017-09-07 | 340759001 | 0.700 ppm |
| 2017-09-07 | 340759001 | 0.747 ppm |
| 2017-10-04 | 347372001 | 0.671 ppm |
| 2017-10-04 | 347372001 | 0.680 ppm |
| 2017-11-07 | 353516001 | 0.690 ppm |
| 2017-11-07 | 353516001 | 0.751 ppm |
| 2017-12-07 | 358304001 | 0.689 ppm |
| 2017-12-07 | 358304001 | 0.830 ppm |
| 2018-01-11 | 362610001 | 0.720 ppm |
| 2018-01-11 | 362610001 | 0.756 ppm |
| 2018-02-06 | 366089001 | 0.714 ppm |
| 2018-02-06 | 366089001 | 0.720 ppm |
| 2018-03-13 | 371408001 | 0.470 ppm |
| 2018-03-13 | 371408001 | 0.680 ppm |
| 2018-04-11 | 376318001 | 0.680 ppm |
| 2018-04-11 | 376318001 | 0.695 ppm |
| 2018-05-08 | 381516001 | 0.430 ppm |
| 2018-05-08 | 381516001 | 0.462 ppm |
| 2018-06-05 | 387211001 | 0.754 ppm |
| 2018-06-05 | 387211001 | 0.820 ppm |
| 2018-07-18 | 395864001 | 0.530 ppm |
| 2018-07-18 | 395864001 | 0.659 ppm |
| 2018-08-23 | 403243001 | 0.660 ppm |
| 2018-08-23 | 403243001 | 0.707 ppm |
| 2018-09-14 | 407802001 | 0.390 ppm |
| 2018-09-14 | 407802001 | 0.639 ppm |
| 2018-10-23 | 416310001 | 0.155 ppm |
| 2018-10-23 | 416310001 | 0.400 ppm |
| 2018-11-19 | 420880001 | 1.11 ppm |
| 2018-11-19 | 420880001 | 1.18 ppm |
| 2018-12-11 | 424239001 | 0.589 ppm |
| 2018-12-11 | 424239001 | 0.650 ppm |
| 2019-01-02 | 426020001 | 0.658 ppm |
| 2019-01-02 | 426020001 | 0.690 ppm |
| 2019-02-19 | 432597001 | 0.779 ppm |
| 2019-02-19 | 432597001 | 0.850 ppm |
| 2019-03-14 | 435578001 | 0.742 ppm |
| 2019-03-14 | 435578001 | 0.780 ppm |
| 2019-04-30 | 443513001 | 0.739 ppm |
| 2019-04-30 | 443513001 | 0.770 ppm |
| 2019-05-09 | 445287001 | 0.802 ppm |
| 2019-05-09 | 445287001 | 0.990 ppm |
| 2019-06-20 | 453349001 | 0.720 ppm |
| 2019-06-20 | 453349001 | 0.733 ppm |
| 2019-07-09 | 457032001 | 0.743 ppm |
| 2019-07-09 | 457032001 | 0.820 ppm |
| 2019-08-13 | 464022001 | 0.554 ppm |
| 2019-08-13 | 464022001 | 0.740 ppm |
| 2019-09-17 | 471422001 | 0.960 ppm |
| 2019-09-17 | 471422001 | 1.36 ppm |
| 2019-10-10 | 475917001 | 0.780 ppm |
| 2019-10-10 | 475917001 | 0.876 ppm |
| 2019-11-19 | 482845001 | 0.560 ppm |
| 2019-11-19 | 482845001 | 0.633 ppm |
| 2019-12-18 | 487267001 | 0.810 ppm |
| 2019-12-18 | 487267001 | 0.820 ppm |