Fluoride
Denver Water Board
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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2013 | N/A | 0 | 0 | N/A |
2014 | 0.563 ppm | 32 | 32 | 0.120 ppm - 0.790 ppm |
2015 | 0.556 ppm | 8 | 8 | 0.230 ppm - 0.680 ppm |
2016 | 0.724 ppm | 34 | 34 | 0.220 ppm - 1.08 ppm |
2017 | 0.691 ppm | 40 | 40 | 0.130 ppm - 0.990 ppm |
2018 | 0.558 ppm | 36 | 35 | ND - 0.760 ppm |
2019 | 0.536 ppm | 30 | 30 | 0.130 ppm - 0.760 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 | Result |
---|---|
2014-04-08 | 0.690 ppm |
2014-04-15 | 0.130 ppm |
2014-04-22 | 0.630 ppm |
2014-05-13 | 0.610 ppm |
2014-05-13 | 0.620 ppm |
2014-05-27 | 0.610 ppm |
2014-05-27 | 0.560 ppm |
2014-05-27 | 0.630 ppm |
2014-05-27 | 0.580 ppm |
2014-06-17 | 0.510 ppm |
2014-06-17 | 0.600 ppm |
2014-06-17 | 0.440 ppm |
2014-07-22 | 0.670 ppm |
2014-07-22 | 0.540 ppm |
2014-07-22 | 0.720 ppm |
2014-08-12 | 0.600 ppm |
2014-08-12 | 0.570 ppm |
2014-08-12 | 0.120 ppm |
2014-08-12 | 0.620 ppm |
2014-08-12 | 0.640 ppm |
2014-08-18 | 0.560 ppm |
2014-09-16 | 0.610 ppm |
2014-09-16 | 0.550 ppm |
2014-09-16 | 0.620 ppm |
2014-10-21 | 0.500 ppm |
2014-10-21 | 0.630 ppm |
2014-11-12 | 0.140 ppm |
2014-11-12 | 0.700 ppm |
2014-11-20 | 0.590 ppm |
2014-11-20 | 0.660 ppm |
2014-12-02 | 0.570 ppm |
2014-12-02 | 0.790 ppm |
2015-01-06 | 0.540 ppm |
2015-01-06 | 0.670 ppm |
2015-02-10 | 0.560 ppm |
2015-02-10 | 0.590 ppm |
2015-02-18 | 0.600 ppm |
2015-02-18 | 0.580 ppm |
2015-03-24 | 0.680 ppm |
2015-03-24 | 0.230 ppm |
2016-01-05 | 0.220 ppm |
2016-01-05 | 0.530 ppm |
2016-01-05 | 0.860 ppm |
2016-02-24 | 0.850 ppm |
2016-02-24 | 0.660 ppm |
2016-02-25 | 0.880 ppm |
2016-03-22 | 0.740 ppm |
2016-03-22 | 1.03 ppm |
2016-03-22 | 0.540 ppm |
2016-04-26 | 0.570 ppm |
2016-04-26 | 1.01 ppm |
2016-04-26 | 0.820 ppm |
2016-05-17 | 0.780 ppm |
2016-05-17 | 1.08 ppm |
2016-05-17 | 0.670 ppm |
2016-06-14 | 0.510 ppm |
2016-06-14 | 0.550 ppm |
2016-06-14 | 0.600 ppm |
2016-07-12 | 0.690 ppm |
2016-07-12 | 0.640 ppm |
2016-07-12 | 0.640 ppm |
2016-08-16 | 0.850 ppm |
2016-08-16 | 0.760 ppm |
2016-08-16 | 0.790 ppm |
2016-08-23 | 0.790 ppm |
2016-08-23 | 0.710 ppm |
2016-08-23 | 0.770 ppm |
2016-09-13 | 0.780 ppm |
2016-09-13 | 0.740 ppm |
2016-09-13 | 0.710 ppm |
2016-10-25 | 0.670 ppm |
2016-10-25 | 0.770 ppm |
2016-11-22 | 0.760 ppm |
2016-11-22 | 0.650 ppm |
2017-01-17 | 0.770 ppm |
2017-01-17 | 0.720 ppm |
2017-02-14 | 0.750 ppm |
2017-02-14 | 0.790 ppm |
2017-02-21 | 0.690 ppm |
2017-03-07 | 0.750 ppm |
2017-03-07 | 0.720 ppm |
2017-03-13 | 0.990 ppm |
2017-03-14 | 0.850 ppm |
2017-04-25 | 0.890 ppm |
2017-04-25 | 0.760 ppm |
2017-05-15 | 0.780 ppm |
2017-05-16 | 0.700 ppm |
2017-05-16 | 0.580 ppm |
2017-05-16 | 0.600 ppm |
2017-06-20 | 0.520 ppm |
2017-06-20 | 0.620 ppm |
2017-06-20 | 0.640 ppm |
2017-06-27 | 0.630 ppm |
2017-06-27 | 0.760 ppm |
2017-06-28 | 0.130 ppm |
2017-07-18 | 0.700 ppm |
2017-07-18 | 0.770 ppm |
2017-07-18 | 0.740 ppm |
2017-08-22 | 0.710 ppm |
2017-08-22 | 0.590 ppm |
2017-08-22 | 0.720 ppm |
2017-08-29 | 0.650 ppm |
2017-08-29 | 0.700 ppm |
2017-09-19 | 0.860 ppm |
2017-09-19 | 0.480 ppm |
2017-09-19 | 0.580 ppm |
2017-10-17 | 0.810 ppm |
2017-10-17 | 0.700 ppm |
2017-10-17 | 0.480 ppm |
2017-11-15 | 0.800 ppm |
2017-11-15 | 0.620 ppm |
2017-11-15 | 0.720 ppm |
2017-11-28 | 0.630 ppm |
2017-11-28 | 0.720 ppm |
2018-01-29 | 0.760 ppm |
2018-02-13 | 0.580 ppm |
2018-02-13 | 0.550 ppm |
2018-03-05 | 0.650 ppm |
2018-03-13 | 0.570 ppm |
2018-03-20 | 0.660 ppm |
2018-03-20 | 0.620 ppm |
2018-04-17 | 0.720 ppm |
2018-04-17 | 0.530 ppm |
2018-04-24 | 0.720 ppm |
2018-05-15 | 0.550 ppm |
2018-05-15 | 0.740 ppm |
2018-05-15 | 0.510 ppm |
2018-06-19 | 0.510 ppm |
2018-06-19 | 0.660 ppm |
2018-06-19 | 0.160 ppm |
2018-07-02 | 0.620 ppm |
2018-07-02 | 0.630 ppm |
2018-07-02 | 0.560 ppm |
2018-08-07 | 0.510 ppm |
2018-08-07 | 0.590 ppm |
2018-08-07 | 0.510 ppm |
2018-09-04 | 0.660 ppm |
2018-09-04 | 0.680 ppm |
2018-09-04 | 0.310 ppm |
2018-09-17 | 0.600 ppm |
2018-09-18 | 0.580 ppm |
2018-09-18 | 0.650 ppm |
2018-09-19 | 0.620 ppm |
2018-10-02 | 0.560 ppm |
2018-10-02 | 0.580 ppm |
2018-10-23 | ND |
2018-11-06 | 0.630 ppm |
2018-11-06 | 0.110 ppm |
2018-12-04 | 0.600 ppm |
2018-12-04 | 0.590 ppm |
2019-01-08 | 0.600 ppm |
2019-01-08 | 0.560 ppm |
2019-02-05 | 0.580 ppm |
2019-02-05 | 0.570 ppm |
2019-03-05 | 0.630 ppm |
2019-03-05 | 0.510 ppm |
2019-04-02 | 0.630 ppm |
2019-04-02 | 0.460 ppm |
2019-05-07 | 0.680 ppm |
2019-05-07 | 0.760 ppm |
2019-05-07 | 0.560 ppm |
2019-06-04 | 0.520 ppm |
2019-06-04 | 0.700 ppm |
2019-06-04 | 0.460 ppm |
2019-07-02 | 0.610 ppm |
2019-07-02 | 0.680 ppm |
2019-07-02 | 0.700 ppm |
2019-08-06 | 0.570 ppm |
2019-08-06 | 0.600 ppm |
2019-08-06 | 0.330 ppm |
2019-09-10 | 0.560 ppm |
2019-09-10 | 0.600 ppm |
2019-09-10 | 0.230 ppm |
2019-10-08 | 0.480 ppm |
2019-10-08 | 0.470 ppm |
2019-10-08 | 0.170 ppm |
2019-11-05 | 0.630 ppm |
2019-11-05 | 0.130 ppm |
2019-12-03 | 0.500 ppm |
2019-12-03 | 0.610 ppm |