Fluoride
Two Rivers 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 | 0.773 ppm | 25 | 25 | 0.700 ppm - 0.940 ppm |
| 2015 | 0.731 ppm | 24 | 24 | 0.642 ppm - 1.03 ppm |
| 2016 | 0.668 ppm | 24 | 24 | 0.590 ppm - 0.780 ppm |
| 2017 | 0.702 ppm | 24 | 24 | 0.625 ppm - 0.820 ppm |
| 2018 | 0.698 ppm | 26 | 26 | 0.510 ppm - 0.880 ppm |
| 2019 | 0.682 ppm | 25 | 25 | 0.577 ppm - 0.780 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 |
|---|---|---|
| 2014-01-06 | 115052001 | 0.758 ppm |
| 2014-01-06 | 115052001 | 0.790 ppm |
| 2014-02-05 | 118839001 | 0.742 ppm |
| 2014-02-05 | 118839001 | 0.780 ppm |
| 2014-03-05 | 122248001 | 0.774 ppm |
| 2014-03-05 | 122248001 | 0.800 ppm |
| 2014-04-02 | 125956001 | 0.785 ppm |
| 2014-04-02 | 125956001 | 0.800 ppm |
| 2014-04-23 | 782152 | 0.730 ppm |
| 2014-05-06 | 131161001 | 0.786 ppm |
| 2014-05-06 | 131161001 | 0.940 ppm |
| 2014-06-03 | 136842001 | 0.734 ppm |
| 2014-06-03 | 136842001 | 0.770 ppm |
| 2014-07-07 | 144113001 | 0.720 ppm |
| 2014-07-07 | 144113001 | 0.760 ppm |
| 2014-08-05 | 149822001 | 0.799 ppm |
| 2014-08-05 | 149822001 | 0.800 ppm |
| 2014-09-02 | 154745001 | 0.724 ppm |
| 2014-09-02 | 154745001 | 0.830 ppm |
| 2014-10-07 | 162551001 | 0.700 ppm |
| 2014-10-07 | 162551001 | 0.731 ppm |
| 2014-11-04 | 167182001 | 0.760 ppm |
| 2014-11-04 | 167182001 | 0.808 ppm |
| 2014-12-02 | 171155001 | 0.722 ppm |
| 2014-12-02 | 171155001 | 0.790 ppm |
| 2015-01-14 | 175884001 | 0.715 ppm |
| 2015-01-14 | 175884001 | 0.820 ppm |
| 2015-02-04 | 178432001 | 0.642 ppm |
| 2015-02-04 | 178432001 | 0.650 ppm |
| 2015-03-03 | 182167001 | 0.716 ppm |
| 2015-03-03 | 182167001 | 0.770 ppm |
| 2015-04-07 | 187045001 | 0.693 ppm |
| 2015-04-07 | 187045001 | 0.800 ppm |
| 2015-05-12 | 193234001 | 0.678 ppm |
| 2015-05-12 | 193234001 | 0.800 ppm |
| 2015-06-02 | 197085001 | 0.698 ppm |
| 2015-06-02 | 197085001 | 0.750 ppm |
| 2015-07-14 | 205581001 | 0.698 ppm |
| 2015-07-14 | 205581001 | 0.710 ppm |
| 2015-08-05 | 210070001 | 0.690 ppm |
| 2015-08-05 | 210070001 | 0.740 ppm |
| 2015-09-01 | 214935001 | 0.665 ppm |
| 2015-09-01 | 214935001 | 0.770 ppm |
| 2015-10-06 | 222409001 | 0.650 ppm |
| 2015-10-06 | 222409001 | 0.677 ppm |
| 2015-11-03 | 226979001 | 0.740 ppm |
| 2015-11-03 | 226979001 | 0.777 ppm |
| 2015-12-08 | 232025001 | 0.653 ppm |
| 2015-12-08 | 232025001 | 1.03 ppm |
| 2016-01-05 | 234558001 | 0.615 ppm |
| 2016-01-05 | 234558001 | 0.710 ppm |
| 2016-02-03 | 238275001 | 0.627 ppm |
| 2016-02-03 | 238275001 | 0.780 ppm |
| 2016-03-01 | 242129001 | 0.618 ppm |
| 2016-03-01 | 242129001 | 0.740 ppm |
| 2016-04-06 | 247513001 | 0.590 ppm |
| 2016-04-06 | 247513001 | 0.590 ppm |
| 2016-05-03 | 252415001 | 0.615 ppm |
| 2016-05-03 | 252415001 | 0.690 ppm |
| 2016-06-14 | 260367001 | 0.686 ppm |
| 2016-06-14 | 260367001 | 0.690 ppm |
| 2016-07-05 | 264417001 | 0.695 ppm |
| 2016-07-05 | 264417001 | 0.760 ppm |
| 2016-08-03 | 270370001 | 0.610 ppm |
| 2016-08-03 | 270370001 | 0.618 ppm |
| 2016-09-07 | 276296001 | 0.666 ppm |
| 2016-09-07 | 276296001 | 0.700 ppm |
| 2016-10-05 | 282723001 | 0.695 ppm |
| 2016-10-05 | 282723001 | 0.710 ppm |
| 2016-11-01 | 286968001 | 0.644 ppm |
| 2016-11-01 | 286968001 | 0.680 ppm |
| 2016-12-07 | 292138001 | 0.637 ppm |
| 2016-12-07 | 292138001 | 0.670 ppm |
| 2017-01-03 | 295077001 | 0.641 ppm |
| 2017-01-03 | 295077001 | 0.750 ppm |
| 2017-02-01 | 298333001 | 0.629 ppm |
| 2017-02-01 | 298333001 | 0.710 ppm |
| 2017-03-07 | 302932001 | 0.692 ppm |
| 2017-03-07 | 302932001 | 0.780 ppm |
| 2017-04-04 | 308263001 | 0.676 ppm |
| 2017-04-04 | 308263001 | 0.770 ppm |
| 2017-05-02 | 313467001 | 0.625 ppm |
| 2017-05-02 | 313467001 | 0.660 ppm |
| 2017-06-07 | 320528001 | 0.680 ppm |
| 2017-06-07 | 320528001 | 0.730 ppm |
| 2017-07-11 | 328279001 | 0.657 ppm |
| 2017-07-11 | 328279001 | 0.700 ppm |
| 2017-08-02 | 333157001 | 0.697 ppm |
| 2017-08-02 | 333157001 | 0.750 ppm |
| 2017-09-06 | 340714001 | 0.750 ppm |
| 2017-09-06 | 340714001 | 0.820 ppm |
| 2017-10-03 | 346742001 | 0.634 ppm |
| 2017-10-03 | 346742001 | 0.670 ppm |
| 2017-11-01 | 352073001 | 0.710 ppm |
| 2017-11-01 | 352073001 | 0.760 ppm |
| 2017-12-06 | 358235001 | 0.660 ppm |
| 2017-12-06 | 358235001 | 0.699 ppm |
| 2018-01-03 | 361296001 | 0.754 ppm |
| 2018-01-03 | 361296001 | 0.830 ppm |
| 2018-01-29 | 1038872 | 0.770 ppm |
| 2018-02-06 | 366091001 | 0.729 ppm |
| 2018-02-06 | 366091001 | 0.780 ppm |
| 2018-03-06 | 369830001 | 0.679 ppm |
| 2018-03-06 | 369830001 | 0.690 ppm |
| 2018-04-03 | 374473001 | 0.510 ppm |
| 2018-04-03 | 374473001 | 0.726 ppm |
| 2018-05-01 | 379420001 | 0.630 ppm |
| 2018-05-01 | 379420001 | 0.654 ppm |
| 2018-06-06 | 386872001 | 0.640 ppm |
| 2018-06-06 | 386872001 | 0.698 ppm |
| 2018-06-26 | 1063877 | 0.570 ppm |
| 2018-07-10 | 393617001 | 0.689 ppm |
| 2018-07-10 | 393617001 | 0.880 ppm |
| 2018-08-08 | 399877001 | 0.604 ppm |
| 2018-08-08 | 399877001 | 0.680 ppm |
| 2018-09-04 | 405116001 | 0.636 ppm |
| 2018-09-04 | 405116001 | 0.660 ppm |
| 2018-10-02 | 412693001 | 0.688 ppm |
| 2018-10-02 | 412693001 | 0.750 ppm |
| 2018-11-07 | 418778001 | 0.675 ppm |
| 2018-11-07 | 418778001 | 0.720 ppm |
| 2018-12-12 | 424257001 | 0.692 ppm |
| 2018-12-12 | 424257001 | 0.810 ppm |
| 2019-01-02 | 425875001 | 0.577 ppm |
| 2019-01-02 | 425875001 | 0.630 ppm |
| 2019-02-05 | 430414001 | 0.608 ppm |
| 2019-02-05 | 430414001 | 0.780 ppm |
| 2019-03-05 | 434362001 | 0.610 ppm |
| 2019-03-05 | 434362001 | 0.627 ppm |
| 2019-03-20 | 1110658 | 0.620 ppm |
| 2019-04-03 | 438694001 | 0.652 ppm |
| 2019-04-03 | 438694001 | 0.760 ppm |
| 2019-05-08 | 445124001 | 0.660 ppm |
| 2019-05-08 | 445124001 | 0.710 ppm |
| 2019-06-05 | 450094001 | 0.669 ppm |
| 2019-06-05 | 450094001 | 0.720 ppm |
| 2019-07-02 | 455439001 | 0.634 ppm |
| 2019-07-02 | 455439001 | 0.690 ppm |
| 2019-08-07 | 462457001 | 0.661 ppm |
| 2019-08-07 | 462457001 | 0.730 ppm |
| 2019-09-04 | 467863001 | 0.686 ppm |
| 2019-09-04 | 467863001 | 0.730 ppm |
| 2019-10-01 | 473956001 | 0.670 ppm |
| 2019-10-01 | 473956001 | 0.717 ppm |
| 2019-11-06 | 480484001 | 0.725 ppm |
| 2019-11-06 | 480484001 | 0.750 ppm |
| 2019-12-04 | 484570001 | 0.713 ppm |
| 2019-12-04 | 484570001 | 0.720 ppm |