Fluoride

Miami Dade Water and Sewer Authority

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.

MORE ABOUT THIS CONTAMINANT

259

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	0.434 ppm	51	51	0.350 ppm - 0.590 ppm
2015	0.444 ppm	31	31	0.330 ppm - 0.610 ppm
2016	0.643 ppm	44	44	0.400 ppm - 0.820 ppm
2017	0.668 ppm	53	53	0.500 ppm - 0.850 ppm
2018	0.655 ppm	36	36	0.540 ppm - 0.810 ppm
2019	0.593 ppm	44	44	0.170 ppm - 0.810 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
2014-01-03	0.480 ppm
2014-01-03	0.500 ppm
2014-01-16	0.480 ppm
2014-01-16	0.440 ppm
2014-02-06	0.360 ppm
2014-02-06	0.370 ppm
2014-02-19	0.363 ppm
2014-02-21	0.410 ppm
2014-02-21	0.480 ppm
2014-03-12	0.350 ppm
2014-03-12	0.510 ppm
2014-03-12	0.350 ppm
2014-03-14	0.440 ppm
2014-03-14	0.450 ppm
2014-03-14	0.400 ppm
2014-04-10	0.400 ppm
2014-04-10	0.420 ppm
2014-04-11	0.470 ppm
2014-04-11	0.410 ppm
2014-05-09	0.490 ppm
2014-05-09	0.360 ppm
2014-05-15	0.410 ppm
2014-05-15	0.370 ppm
2014-06-19	0.440 ppm
2014-06-19	0.410 ppm
2014-06-20	0.500 ppm
2014-06-20	0.410 ppm
2014-07-11	0.410 ppm
2014-07-11	0.480 ppm
2014-07-17	0.460 ppm
2014-07-17	0.480 ppm
2014-08-14	0.410 ppm
2014-08-14	0.390 ppm
2014-08-15	0.480 ppm
2014-08-15	0.410 ppm
2014-09-05	0.440 ppm
2014-09-12	0.500 ppm
2014-09-16	0.380 ppm
2014-09-16	0.370 ppm
2014-10-03	0.510 ppm
2014-10-03	0.440 ppm
2014-10-16	0.590 ppm
2014-10-16	0.520 ppm
2014-11-07	0.540 ppm
2014-11-07	0.420 ppm
2014-11-13	0.400 ppm
2014-11-13	0.400 ppm
2014-12-12	0.410 ppm
2014-12-12	0.450 ppm
2014-12-23	0.350 ppm
2014-12-23	0.400 ppm
2015-01-05	0.460 ppm
2015-01-05	0.440 ppm
2015-01-20	0.450 ppm
2015-01-20	0.460 ppm
2015-02-06	0.340 ppm
2015-02-06	0.480 ppm
2015-02-19	0.450 ppm
2015-02-19	0.480 ppm
2015-03-12	0.420 ppm
2015-03-12	0.450 ppm
2015-03-17	0.410 ppm
2015-03-17	0.450 ppm
2015-04-08	0.360 ppm
2015-04-09	0.330 ppm
2015-04-16	0.460 ppm
2015-04-16	0.410 ppm
2015-05-07	0.340 ppm
2015-05-07	0.400 ppm
2015-05-08	0.400 ppm
2015-05-08	0.530 ppm
2015-06-05	0.410 ppm
2015-06-05	0.500 ppm
2015-06-11	0.560 ppm
2015-06-11	0.550 ppm
2015-07-06	0.540 ppm
2015-07-06	0.450 ppm
2015-07-08	0.390 ppm
2015-07-08	0.450 ppm
2015-08-06	0.610 ppm
2015-08-06	0.380 ppm
2015-08-11	0.400 ppm
2016-02-11	0.450 ppm
2016-02-11	0.470 ppm
2016-02-12	0.460 ppm
2016-02-12	0.400 ppm
2016-03-10	0.530 ppm
2016-03-10	0.570 ppm
2016-03-17	0.820 ppm
2016-03-17	0.730 ppm
2016-04-13	0.530 ppm
2016-04-13	0.530 ppm
2016-04-21	0.700 ppm
2016-04-21	0.500 ppm
2016-05-03	0.640 ppm
2016-05-03	0.790 ppm
2016-05-12	0.610 ppm
2016-05-12	0.450 ppm
2016-06-09	0.640 ppm
2016-06-09	0.600 ppm
2016-06-23	0.710 ppm
2016-06-23	0.710 ppm
2016-07-12	0.790 ppm
2016-07-12	0.710 ppm
2016-07-14	0.620 ppm
2016-07-14	0.560 ppm
2016-08-02	0.650 ppm
2016-08-02	0.670 ppm
2016-08-17	0.690 ppm
2016-08-17	0.720 ppm
2016-09-08	0.680 ppm
2016-09-08	0.620 ppm
2016-09-15	0.730 ppm
2016-09-15	0.720 ppm
2016-10-04	0.760 ppm
2016-10-04	0.700 ppm
2016-10-20	0.750 ppm
2016-10-20	0.730 ppm
2016-11-17	0.690 ppm
2016-11-17	0.700 ppm
2016-11-18	0.770 ppm
2016-11-18	0.630 ppm
2016-12-09	0.600 ppm
2016-12-09	0.630 ppm
2016-12-22	0.680 ppm
2016-12-22	0.660 ppm
2017-01-18	0.630 ppm
2017-01-19	0.790 ppm
2017-01-19	0.510 ppm
2017-01-19	0.660 ppm
2017-01-19	0.760 ppm
2017-01-25	0.810 ppm
2017-01-25	0.810 ppm
2017-02-02	0.680 ppm
2017-02-02	0.680 ppm
2017-02-10	0.530 ppm
2017-02-10	0.680 ppm
2017-02-16	0.790 ppm
2017-02-16	0.690 ppm
2017-02-22	0.630 ppm
2017-02-22	0.680 ppm
2017-03-09	0.550 ppm
2017-03-09	0.700 ppm
2017-03-16	0.750 ppm
2017-03-16	0.800 ppm
2017-04-07	0.500 ppm
2017-04-07	0.570 ppm
2017-04-13	0.680 ppm
2017-04-13	0.640 ppm
2017-05-05	0.610 ppm
2017-05-05	0.560 ppm
2017-05-18	0.820 ppm
2017-05-18	0.840 ppm
2017-06-16	0.520 ppm
2017-06-19	0.610 ppm
2017-06-19	0.790 ppm
2017-07-03	0.610 ppm
2017-07-03	0.580 ppm
2017-07-14	0.740 ppm
2017-07-14	0.690 ppm
2017-08-17	0.830 ppm
2017-08-17	0.850 ppm
2017-08-18	0.660 ppm
2017-08-18	0.670 ppm
2017-09-18	0.500 ppm
2017-09-18	0.520 ppm
2017-09-21	0.740 ppm
2017-09-21	0.720 ppm
2017-10-03	0.530 ppm
2017-10-03	0.580 ppm
2017-10-11	0.780 ppm
2017-10-11	0.750 ppm
2017-11-09	0.580 ppm
2017-11-09	0.620 ppm
2017-11-09	0.650 ppm
2017-12-04	0.590 ppm
2017-12-04	0.500 ppm
2017-12-14	0.720 ppm
2017-12-14	0.710 ppm
2018-01-02	0.570 ppm
2018-01-02	0.620 ppm
2018-01-10	0.690 ppm
2018-01-10	0.680 ppm
2018-02-09	0.620 ppm
2018-02-09	0.540 ppm
2018-02-15	0.690 ppm
2018-02-15	0.690 ppm
2018-04-05	0.690 ppm
2018-04-05	0.630 ppm
2018-04-05	0.660 ppm
2018-04-05	0.680 ppm
2018-05-07	0.610 ppm
2018-05-07	0.650 ppm
2018-05-17	0.750 ppm
2018-05-17	0.720 ppm
2018-06-08	0.600 ppm
2018-06-08	0.560 ppm
2018-06-14	0.670 ppm
2018-06-14	0.740 ppm
2018-07-11	0.630 ppm
2018-07-11	0.580 ppm
2018-07-19	0.680 ppm
2018-07-20	0.810 ppm
2018-08-07	0.650 ppm
2018-08-07	0.630 ppm
2018-08-16	0.750 ppm
2018-08-16	0.640 ppm
2018-11-14	0.590 ppm
2018-11-14	0.550 ppm
2018-11-14	0.790 ppm
2018-11-14	0.710 ppm
2018-12-04	0.630 ppm
2018-12-04	0.570 ppm
2018-12-13	0.710 ppm
2018-12-13	0.610 ppm
2019-01-02	0.640 ppm
2019-01-02	0.570 ppm
2019-01-17	0.700 ppm
2019-01-17	0.660 ppm
2019-02-11	0.640 ppm
2019-02-11	0.570 ppm
2019-02-14	0.660 ppm
2019-02-14	0.700 ppm
2019-03-14	0.740 ppm
2019-03-14	0.700 ppm
2019-03-15	0.170 ppm
2019-03-15	0.180 ppm
2019-04-01	0.520 ppm
2019-04-01	0.660 ppm
2019-04-11	0.260 ppm
2019-04-11	0.350 ppm
2019-05-02	0.520 ppm
2019-05-02	0.590 ppm
2019-05-09	0.650 ppm
2019-05-09	0.670 ppm
2019-06-13	0.710 ppm
2019-06-13	0.740 ppm
2019-06-14	0.550 ppm
2019-06-14	0.400 ppm
2019-08-02	0.520 ppm
2019-08-02	0.410 ppm
2019-08-15	0.760 ppm
2019-08-15	0.630 ppm
2019-09-09	0.520 ppm
2019-09-09	0.460 ppm
2019-09-19	0.700 ppm
2019-09-19	0.810 ppm
2019-10-09	0.730 ppm
2019-10-09	0.760 ppm
2019-10-10	0.530 ppm
2019-10-10	0.500 ppm
2019-11-13	0.720 ppm
2019-11-13	0.730 ppm
2019-11-20	0.590 ppm
2019-11-21	0.530 ppm
2019-12-09	0.600 ppm
2019-12-09	0.580 ppm
2019-12-12	0.720 ppm
2019-12-12	0.730 ppm