Fluoride
Arlington 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 | 0.690 ppm | 26 | 24 | ND - 1.000 ppm |
| 2015 | 0.717 ppm | 24 | 24 | 0.477 ppm - 0.900 ppm |
| 2016 | 0.769 ppm | 24 | 24 | 0.581 ppm - 0.900 ppm |
| 2017 | 0.574 ppm | 26 | 26 | 0.0970 ppm - 1.10 ppm |
| 2018 | 0.628 ppm | 26 | 26 | 0.257 ppm - 0.800 ppm |
| 2019 | 0.693 ppm | 24 | 24 | 0.582 ppm - 0.858 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 |
|---|---|---|
| 2014-01-17 | 116578001 | 0.938 ppm |
| 2014-01-17 | 116578001 | 1.000 ppm |
| 2014-02-24 | 120879001 | 0.863 ppm |
| 2014-02-24 | 120879001 | 1.000 ppm |
| 2014-03-20 | 124384001 | 0.744 ppm |
| 2014-03-20 | 124384001 | 0.800 ppm |
| 2014-04-18 | 128283001 | 0.762 ppm |
| 2014-04-18 | 128283001 | 0.900 ppm |
| 2014-05-23 | 134702001 | 0.600 ppm |
| 2014-05-23 | 134702001 | 0.653 ppm |
| 2014-06-20 | 471099 | ND |
| 2014-06-20 | 471107 | ND |
| 2014-06-26 | 141859001 | 0.500 ppm |
| 2014-06-26 | 141859001 | 0.619 ppm |
| 2014-07-25 | 147620001 | 0.600 ppm |
| 2014-07-25 | 147620001 | 0.711 ppm |
| 2014-08-22 | 153074001 | 0.800 ppm |
| 2014-08-22 | 153074001 | 0.832 ppm |
| 2014-09-29 | 160422001 | 0.700 ppm |
| 2014-09-29 | 160422001 | 0.790 ppm |
| 2014-10-24 | 165459001 | 0.731 ppm |
| 2014-10-24 | 165459001 | 0.800 ppm |
| 2014-11-14 | 168522001 | 0.700 ppm |
| 2014-11-14 | 168522001 | 0.700 ppm |
| 2014-12-05 | 171313001 | 0.595 ppm |
| 2014-12-05 | 171313001 | 0.600 ppm |
| 2015-01-23 | 176920001 | 0.653 ppm |
| 2015-01-23 | 176920001 | 0.700 ppm |
| 2015-02-20 | 180501001 | 0.628 ppm |
| 2015-02-20 | 180501001 | 0.700 ppm |
| 2015-03-20 | 184460001 | 0.660 ppm |
| 2015-03-20 | 184460001 | 0.900 ppm |
| 2015-04-24 | 189764001 | 0.621 ppm |
| 2015-04-24 | 189764001 | 0.800 ppm |
| 2015-05-15 | 193824001 | 0.477 ppm |
| 2015-05-15 | 193824001 | 0.600 ppm |
| 2015-06-26 | 202273001 | 0.774 ppm |
| 2015-06-26 | 202273001 | 0.800 ppm |
| 2015-07-24 | 207831001 | 0.500 ppm |
| 2015-07-24 | 207831001 | 0.625 ppm |
| 2015-08-22 | 213753001 | 0.600 ppm |
| 2015-08-22 | 213753001 | 0.765 ppm |
| 2015-09-25 | 220211001 | 0.700 ppm |
| 2015-09-25 | 220211001 | 0.872 ppm |
| 2015-10-29 | 226182001 | 0.700 ppm |
| 2015-10-29 | 226182001 | 0.867 ppm |
| 2015-11-19 | 229701001 | 0.800 ppm |
| 2015-11-19 | 229701001 | 0.813 ppm |
| 2015-12-16 | 233315001 | 0.800 ppm |
| 2015-12-16 | 233315001 | 0.864 ppm |
| 2016-01-21 | 236729001 | 0.581 ppm |
| 2016-01-21 | 236729001 | 0.700 ppm |
| 2016-02-18 | 240409001 | 0.661 ppm |
| 2016-02-18 | 240409001 | 0.800 ppm |
| 2016-03-28 | 245918001 | 0.638 ppm |
| 2016-03-28 | 245918001 | 0.800 ppm |
| 2016-04-27 | 251118001 | 0.670 ppm |
| 2016-04-27 | 251118001 | 0.800 ppm |
| 2016-05-19 | 255775001 | 0.700 ppm |
| 2016-05-19 | 255775001 | 0.700 ppm |
| 2016-06-22 | 262289001 | 0.646 ppm |
| 2016-06-22 | 262289001 | 0.700 ppm |
| 2016-07-19 | 267194001 | 0.661 ppm |
| 2016-07-19 | 267194001 | 0.700 ppm |
| 2016-08-26 | 274411001 | 0.770 ppm |
| 2016-08-26 | 274411001 | 0.900 ppm |
| 2016-09-27 | 280763001 | 0.889 ppm |
| 2016-09-27 | 280763001 | 0.900 ppm |
| 2016-10-21 | 285293001 | 0.876 ppm |
| 2016-10-21 | 285293001 | 0.900 ppm |
| 2016-11-28 | 290347001 | 0.806 ppm |
| 2016-11-28 | 290347001 | 0.900 ppm |
| 2016-12-29 | 294454001 | 0.852 ppm |
| 2016-12-29 | 294454001 | 0.900 ppm |
| 2017-01-30 | 297906001 | 0.878 ppm |
| 2017-01-30 | 297906001 | 0.900 ppm |
| 2017-02-10 | 299542001 | 0.726 ppm |
| 2017-02-10 | 299542001 | 0.900 ppm |
| 2017-03-24 | 306050001 | 0.908 ppm |
| 2017-03-24 | 306050001 | 1.10 ppm |
| 2017-04-28 | 312470001 | 0.448 ppm |
| 2017-04-28 | 312470001 | 0.500 ppm |
| 2017-05-19 | 316987001 | 0.385 ppm |
| 2017-05-19 | 316987001 | 0.500 ppm |
| 2017-06-23 | 324269001 | 0.406 ppm |
| 2017-06-23 | 324269001 | 0.600 ppm |
| 2017-07-24 | 330939001 | 0.400 ppm |
| 2017-07-24 | 330939001 | 0.466 ppm |
| 2017-08-03 | 334914001 | 0.497 ppm |
| 2017-08-03 | 334914001 | 0.500 ppm |
| 2017-08-16 | 907215 | 0.0970 ppm |
| 2017-08-16 | 907224 | 0.220 ppm |
| 2017-09-06 | 340497001 | 0.496 ppm |
| 2017-09-06 | 340497001 | 0.600 ppm |
| 2017-10-02 | 346402001 | 0.600 ppm |
| 2017-10-02 | 346402001 | 0.637 ppm |
| 2017-11-09 | 353691001 | 0.527 ppm |
| 2017-11-09 | 353691001 | 0.700 ppm |
| 2017-12-04 | 357445001 | 0.329 ppm |
| 2017-12-04 | 357445001 | 0.600 ppm |
| 2018-01-02 | 360912001 | 0.257 ppm |
| 2018-01-02 | 360912001 | 0.600 ppm |
| 2018-02-08 | 366178001 | 0.349 ppm |
| 2018-02-08 | 366178001 | 0.800 ppm |
| 2018-03-05 | 369636001 | 0.286 ppm |
| 2018-03-05 | 369636001 | 0.750 ppm |
| 2018-03-09 | 370313001 | 0.344 ppm |
| 2018-03-09 | 370313001 | 0.460 ppm |
| 2018-04-02 | 373738001 | 0.776 ppm |
| 2018-04-02 | 373738001 | 0.800 ppm |
| 2018-05-01 | 379419001 | 0.695 ppm |
| 2018-05-01 | 379419001 | 0.700 ppm |
| 2018-06-11 | 387368001 | 0.680 ppm |
| 2018-06-11 | 387368001 | 0.784 ppm |
| 2018-07-02 | 391766001 | 0.670 ppm |
| 2018-07-02 | 391766001 | 0.714 ppm |
| 2018-08-06 | 398600001 | 0.757 ppm |
| 2018-08-06 | 398600001 | 0.760 ppm |
| 2018-09-04 | 404544001 | 0.657 ppm |
| 2018-09-04 | 404544001 | 0.700 ppm |
| 2018-10-01 | 411235001 | 0.600 ppm |
| 2018-10-01 | 411235001 | 0.674 ppm |
| 2018-11-05 | 417569001 | 0.557 ppm |
| 2018-11-05 | 417569001 | 0.640 ppm |
| 2018-12-03 | 421904001 | 0.582 ppm |
| 2018-12-03 | 421904001 | 0.740 ppm |
| 2019-01-03 | 425970001 | 0.639 ppm |
| 2019-01-03 | 425970001 | 0.710 ppm |
| 2019-02-14 | 431417001 | 0.582 ppm |
| 2019-02-14 | 431417001 | 0.620 ppm |
| 2019-03-01 | 433233001 | 0.659 ppm |
| 2019-03-01 | 433233001 | 0.670 ppm |
| 2019-04-01 | 437739001 | 0.684 ppm |
| 2019-04-01 | 437739001 | 0.690 ppm |
| 2019-05-01 | 443176001 | 0.700 ppm |
| 2019-05-01 | 443176001 | 0.701 ppm |
| 2019-06-04 | 449435001 | 0.660 ppm |
| 2019-06-04 | 449435001 | 0.680 ppm |
| 2019-07-01 | 454742001 | 0.650 ppm |
| 2019-07-01 | 454742001 | 0.669 ppm |
| 2019-08-01 | 460830001 | 0.670 ppm |
| 2019-08-01 | 460830001 | 0.710 ppm |
| 2019-09-03 | 466956001 | 0.690 ppm |
| 2019-09-03 | 466956001 | 0.702 ppm |
| 2019-10-04 | 474471001 | 0.730 ppm |
| 2019-10-04 | 474471001 | 0.858 ppm |
| 2019-11-01 | 479107001 | 0.750 ppm |
| 2019-11-01 | 479107001 | 0.823 ppm |
| 2019-12-02 | 483602001 | 0.679 ppm |
| 2019-12-02 | 483602001 | 0.700 ppm |