Fluoride
Milton Water Department
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 | 0.575 ppm | 13 | 12 | ND - 1.10 ppm |
| 2015 | 0.673 ppm | 13 | 13 | 0.390 ppm - 0.880 ppm |
| 2016 | 0.610 ppm | 12 | 12 | 0.280 ppm - 0.790 ppm |
| 2017 | 0.596 ppm | 14 | 14 | 0.340 ppm - 0.740 ppm |
| 2018 | 0.639 ppm | 13 | 13 | 0.300 ppm - 0.781 ppm |
| 2019 | 0.356 ppm | 14 | 14 | 0.165 ppm - 0.863 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 |
|---|---|---|
| 2014-01-30 | S505670 | ND |
| 2014-02-27 | S505683 | 0.290 ppm |
| 2014-03-27 | S505631 | 0.270 ppm |
| 2014-04-30 | S505575 | 0.580 ppm |
| 2014-05-29 | S505568 | 0.450 ppm |
| 2014-07-31 | S505642 | 0.880 ppm |
| 2014-09-02 | S505641 | 1.04 ppm |
| 2014-09-25 | S505647 | 0.670 ppm |
| 2014-10-29 | S507435 | 0.630 ppm |
| 2014-11-25 | S507440 | 1.10 ppm |
| 2014-12-10 | S588981 | 0.500 ppm |
| 2014-12-10 | S588980 | 0.500 ppm |
| 2014-12-11 | S507444 | 0.570 ppm |
| 2015-01-27 | S507448 | 0.880 ppm |
| 2015-03-02 | S505610 | 0.850 ppm |
| 2015-03-31 | S514386 | 0.710 ppm |
| 2015-04-28 | S514394 | 0.690 ppm |
| 2015-05-05 | S514398 | 0.840 ppm |
| 2015-05-29 | S505699 | 0.760 ppm |
| 2015-06-18 | S505593 | 0.710 ppm |
| 2015-07-16 | S514402 | 0.750 ppm |
| 2015-08-13 | S514406 | 0.400 ppm |
| 2015-09-29 | S514411 | 0.390 ppm |
| 2015-10-22 | S629190 | 0.610 ppm |
| 2015-11-24 | S629220 | 0.450 ppm |
| 2015-12-16 | S629224 | 0.710 ppm |
| 2016-01-13 | S629228 | 0.580 ppm |
| 2016-02-25 | S505598 | 0.550 ppm |
| 2016-03-16 | S514415 | 0.590 ppm |
| 2016-04-21 | S505602 | 0.760 ppm |
| 2016-05-25 | S505705 | 0.670 ppm |
| 2016-06-23 | S505709 | 0.680 ppm |
| 2016-07-20 | S505584 | 0.280 ppm |
| 2016-08-25 | S505588 | 0.620 ppm |
| 2016-09-14 | S629194 | 0.520 ppm |
| 2016-10-19 | S514371 | 0.790 ppm |
| 2016-11-17 | S514375 | 0.660 ppm |
| 2016-12-20 | S514379 | 0.620 ppm |
| 2017-01-19 | S620714 | 0.660 ppm |
| 2017-02-15 | S620726 | 0.700 ppm |
| 2017-03-15 | S620718 | 0.740 ppm |
| 2017-04-18 | S690489 | 0.690 ppm |
| 2017-05-24 | S690459 | 0.430 ppm |
| 2017-06-14 | S690494 | 0.340 ppm |
| 2017-07-13 | S690464 | 0.580 ppm |
| 2017-08-15 | S690504 | 0.690 ppm |
| 2017-09-13 | S690468 | 0.630 ppm |
| 2017-09-15 | S750406 | 0.590 ppm |
| 2017-10-24 | S690509 | 0.720 ppm |
| 2017-11-13 | S750421 | 0.450 ppm |
| 2017-11-21 | S690513 | 0.570 ppm |
| 2017-12-13 | S690518 | 0.560 ppm |
| 2018-01-23 | S690474 | 0.630 ppm |
| 2018-02-14 | S690479 | 0.300 ppm |
| 2018-03-14 | S690483 | 0.500 ppm |
| 2018-04-25 | S690488 | 0.591 ppm |
| 2018-05-16 | S751883 | 0.653 ppm |
| 2018-06-20 | S751887 | 0.723 ppm |
| 2018-07-11 | S751891 | 0.706 ppm |
| 2018-08-28 | S751865 | 0.765 ppm |
| 2018-09-18 | S751869 | 0.599 ppm |
| 2018-10-17 | S751873 | 0.781 ppm |
| 2018-11-14 | S751877 | 0.740 ppm |
| 2018-11-19 | S808783 | 0.662 ppm |
| 2018-12-13 | S690521 | 0.660 ppm |
| 2019-01-17 | S351053 | 0.863 ppm |
| 2019-02-13 | S751902 | 0.331 ppm |
| 2019-02-20 | S866519 | 0.355 ppm |
| 2019-03-21 | S741126 | 0.467 ppm |
| 2019-03-26 | S690526 | 0.633 ppm |
| 2019-04-24 | S690531 | 0.694 ppm |
| 2019-05-29 | S741105 | 0.165 ppm |
| 2019-06-19 | S741110 | 0.215 ppm |
| 2019-07-29 | S857283 | 0.200 ppm |
| 2019-08-27 | S857288 | 0.253 ppm |
| 2019-09-30 | S895782 | 0.222 ppm |
| 2019-10-17 | S895788 | 0.237 ppm |
| 2019-11-19 | S895752 | 0.187 ppm |
| 2019-12-23 | S895757 | 0.170 ppm |