Fluoride
Town of Gilbert
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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.620 ppm | 1 | 1 | 0.620 ppm |
| 2015 | 0.510 ppm | 1 | 1 | 0.510 ppm |
| 2016 | 0.579 ppm | 10 | 10 | 0.280 ppm - 0.940 ppm |
| 2017 | 0.650 ppm | 1 | 1 | 0.650 ppm |
| 2018 | 0.696 ppm | 17 | 17 | 0.370 ppm - 0.960 ppm |
| 2019 | 0.685 ppm | 17 | 17 | 0.360 ppm - 0.940 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 |
|---|---|---|
| 2014-01-27 | 201401270086I | 0.620 ppm |
| 2015-01-28 | 201501280356I | 0.510 ppm |
| 2016-01-12 | 201601120223I | 0.560 ppm |
| 2016-01-19 | 201601190321I | 0.690 ppm |
| 2016-01-26 | 201601260298I | 0.940 ppm |
| 2016-02-08 | 201602080053I | 0.280 ppm |
| 2016-02-08 | 201602080042I | 0.470 ppm |
| 2016-03-02 | 201603020441I | 0.500 ppm |
| 2016-03-23 | 201603230453I | 0.560 ppm |
| 2016-04-07 | 201604070686I | 0.690 ppm |
| 2016-04-19 | 201604190185I | 0.470 ppm |
| 2016-05-31 | 201605310460I | 0.630 ppm |
| 2017-01-04 | 2017010408151 | 0.650 ppm |
| 2018-01-16 | 201801160489 I | 0.370 ppm |
| 2018-01-16 | 201801160478 I | 0.750 ppm |
| 2018-01-16 | 201801160477 I | 0.580 ppm |
| 2018-01-24 | 201801240891 I | 0.780 ppm |
| 2018-01-24 | 201801240738 I | 0.500 ppm |
| 2018-01-24 | 201801240730 I | 0.860 ppm |
| 2018-01-29 | 201801290255 I | 0.780 ppm |
| 2018-01-29 | 201801290249 I | 0.610 ppm |
| 2018-01-29 | 201801290172 I | 0.710 ppm |
| 2018-02-26 | 201802260220 I | 0.960 ppm |
| 2018-02-27 | 201802270449 I | 0.460 ppm |
| 2018-03-20 | 201803200269 I | 0.620 ppm |
| 2018-03-20 | 201803200261 I | 0.770 ppm |
| 2018-03-21 | 201803210471 I | 0.680 ppm |
| 2018-05-17 | 201805170725 I | 0.720 ppm |
| 2018-05-29 | 201805290454 I | 0.750 ppm |
| 2018-06-13 | 201806131020 I | 0.940 ppm |
| 2019-01-09 | 2019010903741 | 0.710 ppm |
| 2019-01-09 | 2019010903421 | 0.720 ppm |
| 2019-01-09 | 2019010903471 | 0.940 ppm |
| 2019-01-09 | 2019010903551 | 0.790 ppm |
| 2019-01-09 | 2019010903691 | 0.920 ppm |
| 2019-01-09 | 2019010903791 | 0.720 ppm |
| 2019-01-09 | 201901090384I | 0.360 ppm |
| 2019-01-09 | 201901090393I | 0.790 ppm |
| 2019-01-09 | 201901090396I | 0.570 ppm |
| 2019-01-15 | 2019011502201 | 0.630 ppm |
| 2019-02-06 | 2019020602301 | 0.830 ppm |
| 2019-02-06 | 2019020602271 | 0.500 ppm |
| 2019-02-06 | 2019020602161 | 0.710 ppm |
| 2019-03-25 | 201903250230I | 0.600 ppm |
| 2019-03-25 | 2019032501821 | 0.720 ppm |
| 2019-04-16 | 2019041604191 | 0.650 ppm |
| 2019-04-29 | 2019042902961 | 0.490 ppm |