Fluoride

Hawthorne Water Department

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

182

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	0.669 ppm	31	31	0.300 ppm - 0.959 ppm
2015	0.609 ppm	30	30	0.348 ppm - 0.859 ppm
2016	0.605 ppm	30	30	0.368 ppm - 0.808 ppm
2017	0.628 ppm	31	31	0.337 ppm - 0.785 ppm
2018	0.722 ppm	30	30	0.546 ppm - 0.831 ppm
2019	0.664 ppm	30	30	0.498 ppm - 0.807 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
2014-01-08	5810-006-1044	0.690 ppm
2014-01-08	5810-801-0928	0.670 ppm
2014-01-08	5810-802-1034	0.810 ppm
2014-02-04	5810-006-1130	0.540 ppm
2014-02-04	5810-800-1145	0.650 ppm
2014-03-11	5810-006-0905	0.660 ppm
2014-03-11	5810-801-0950	0.710 ppm
2014-03-11	5810-802-1115	0.480 ppm
2014-04-09	5810-006-1105	0.850 ppm
2014-04-09	5810-800-1045	0.310 ppm
2014-05-07	5810-006-1038	0.800 ppm
2014-05-07	5810-801-0930	0.720 ppm
2014-05-07	5810-802-1026	0.520 ppm
2014-06-11	5810-006-1004	0.800 ppm
2014-06-11	5810-800-0854	0.540 ppm
2014-07-02	5810-004-0950	0.300 ppm
2014-07-02	5810-006-0940	0.810 ppm
2014-07-02	5810-801-1055	0.730 ppm
2014-07-02	5810-802-1130	0.420 ppm
2014-08-05	5701-006-0900	0.959 ppm
2014-08-05	5701-800-0920	0.889 ppm
2014-09-09	5701-006-0910	0.842 ppm
2014-09-09	5701-801-0945	0.767 ppm
2014-09-09	5701-802-1125	0.624 ppm
2014-10-08	5701-006-0950	0.693 ppm
2014-10-08	5701-800-1000	0.613 ppm
2014-11-04	5701-006-0845	0.654 ppm
2014-11-04	5701-801-1145	0.746 ppm
2014-11-04	5701-802-1115	0.490 ppm
2014-12-10	5701-006-0750	0.836 ppm
2014-12-10	5701-800-0825	0.619 ppm
2015-01-08	5701-006-1550	0.744 ppm
2015-01-08	5701-801-1316	0.617 ppm
2015-01-08	5701-802-1405	0.438 ppm
2015-02-04	5701-006-1120	0.859 ppm
2015-02-04	5701-800-1240	0.548 ppm
2015-03-10	5701-006-0755	0.802 ppm
2015-03-10	5701-801-0936	0.613 ppm
2015-03-10	5701-802-1120	0.483 ppm
2015-04-08	5701-006-0815	0.783 ppm
2015-04-08	5701-800-0815	0.573 ppm
2015-05-05	5701-006-1350	0.503 ppm
2015-05-05	5701-801-1405	0.667 ppm
2015-05-05	5701-802-1440	0.479 ppm
2015-06-02	5701-006-1110	0.619 ppm
2015-06-02	5701-800-0918	0.504 ppm
2015-07-13	5701-006-0830	0.642 ppm
2015-07-13	5701-801-0902	0.588 ppm
2015-07-13	5701-802-0950	0.734 ppm
2015-08-04	5701-006-1140	0.791 ppm
2015-08-04	5701-800-0950	0.769 ppm
2015-09-16	5701-006-1005	0.538 ppm
2015-09-16	5701-801-1024	0.473 ppm
2015-09-16	5701-802-1146	0.348 ppm
2015-10-06	5701-006-0830	0.555 ppm
2015-10-06	5701-800-0926	0.423 ppm
2015-11-10	5701-006-0830	0.668 ppm
2015-11-10	5701-801-0845	0.649 ppm
2015-11-10	5701-802-0920	0.701 ppm
2015-12-08	5701-006-0810	0.605 ppm
2015-12-08	5701-800-0914	0.564 ppm
2016-01-04	5701-006-1018	0.563 ppm
2016-01-04	5701-801-1032	0.466 ppm
2016-01-04	5701-802-1114	0.368 ppm
2016-02-02	5701-006-1145	0.374 ppm
2016-02-02	5701-800-0952	0.509 ppm
2016-03-02	5701-006-0815	0.603 ppm
2016-03-02	5701-801-0925	0.608 ppm
2016-03-02	5701-802-1015	0.598 ppm
2016-04-05	5701-006-1314	0.383 ppm
2016-04-05	5701-800-1113	0.503 ppm
2016-05-03	5701-006-1125	0.582 ppm
2016-05-03	5701-801-0949	0.743 ppm
2016-05-03	5701-802-1119	0.708 ppm
2016-06-07	5701-006-1530	0.728 ppm
2016-06-07	5701-800-0925	0.672 ppm
2016-07-06	5701-006-0856	0.677 ppm
2016-07-06	5701-801-0916	0.688 ppm
2016-07-06	5701-802-1037	0.712 ppm
2016-08-03	5701-006-0835	0.671 ppm
2016-08-03	5701-800-0957	0.526 ppm
2016-09-20	5701-006-1011	0.644 ppm
2016-09-20	5701-801-1047	0.650 ppm
2016-09-20	5701-802-1301	0.449 ppm
2016-10-13	5701-006-0825	0.729 ppm
2016-10-13	5701-800-0940	0.500 ppm
2016-11-02	5701-006-0918	0.711 ppm
2016-11-02	5701-801-0943	0.694 ppm
2016-11-02	5701-802-1021	0.688 ppm
2016-12-06	5701-006-0800	0.808 ppm
2016-12-06	5701-800-1042	0.592 ppm
2017-01-24	5701-006-1202	0.785 ppm
2017-01-24	5701-801-0957	0.680 ppm
2017-01-24	5701-802-1141	0.748 ppm
2017-02-14	5701-006-0920	0.681 ppm
2017-02-14	5701-800-0956	0.687 ppm
2017-03-07	5701-006-0810	0.676 ppm
2017-03-07	5701-801-0930	0.683 ppm
2017-03-07	5701-802-1108	0.678 ppm
2017-04-21	5701-006-1535	0.662 ppm
2017-04-21	5701-800-0916	0.656 ppm
2017-05-08	5701-006-0820	0.652 ppm
2017-05-08	5701-801-0902	0.642 ppm
2017-05-08	5701-802-0951	0.647 ppm
2017-06-06	5701-006-1540	0.706 ppm
2017-06-06	5701-800-0858	0.546 ppm
2017-07-11	5701-006-0815	0.638 ppm
2017-07-11	5701-801-0926	0.623 ppm
2017-07-11	5701-802-1110	0.442 ppm
2017-07-18	5810-004-1330	0.340 ppm
2017-08-08	5701-006-0830	0.676 ppm
2017-08-08	5701-800-0858	0.689 ppm
2017-09-06	5701-006-0756	0.627 ppm
2017-09-06	5701-801-0844	0.603 ppm
2017-09-06	5701-802-1000	0.573 ppm
2017-10-11	5701-006-1135	0.665 ppm
2017-10-11	5701-800-1000	0.337 ppm
2017-11-14	5701-006-0850	0.736 ppm
2017-11-14	5701-801-0955	0.640 ppm
2017-11-14	5701-802-1235	0.448 ppm
2017-12-05	5701-006-0807	0.689 ppm
2017-12-05	5701-800-0915	0.611 ppm
2018-01-09	5701-006-0826	0.715 ppm
2018-01-09	5701-801-0941	0.685 ppm
2018-01-09	5701-802-1107	0.710 ppm
2018-02-13	5701-006-1457	0.738 ppm
2018-02-13	5701-800-0954	0.652 ppm
2018-03-07	5701-006-0835	0.692 ppm
2018-03-07	5701-801-0934	0.689 ppm
2018-03-07	5701-802-1034	0.714 ppm
2018-04-10	5701-006-0818	0.814 ppm
2018-04-10	5701-800-0911	0.700 ppm
2018-05-02	5701-006-0905	0.731 ppm
2018-05-02	5701-801-1402	0.715 ppm
2018-05-02	5701-802-1448	0.750 ppm
2018-06-06	5701-006-0745	0.789 ppm
2018-06-06	5701-800-0845	0.717 ppm
2018-07-05	5701-006-0820	0.749 ppm
2018-07-05	5701-801-0910	0.675 ppm
2018-07-05	5701-802-1005	0.694 ppm
2018-08-14	5701-006-1305	0.682 ppm
2018-08-14	5701-800-0955	0.582 ppm
2018-09-04	5701-006-1550	0.793 ppm
2018-09-04	5701-801-1040	0.698 ppm
2018-09-04	5701-802-1225	0.698 ppm
2018-10-10	5701-006-0900	0.831 ppm
2018-10-10	5701-800-0930	0.733 ppm
2018-11-07	5701-006-0910	0.826 ppm
2018-11-07	5701-801-0950	0.815 ppm
2018-11-07	5701-802-1045	0.801 ppm
2018-12-04	5701-006-0925	0.546 ppm
2018-12-04	5701-800-0945	0.721 ppm
2019-01-08	5701-006-0945	0.564 ppm
2019-01-08	5701-801-1025	0.752 ppm
2019-01-08	5701-802-1215	0.626 ppm
2019-02-12	5701-006-1545	0.795 ppm
2019-02-12	5701-800-0930	0.789 ppm
2019-03-12	5701-006-0840	0.649 ppm
2019-03-12	5701-801-1200	0.745 ppm
2019-03-12	5701-802-1125	0.512 ppm
2019-04-02	5810-006-0840	0.620 ppm
2019-04-02	5810-800-0950	0.520 ppm
2019-05-07	5701-006-0615	0.716 ppm
2019-05-07	5701-801-0655	0.701 ppm
2019-05-07	5701-802-0810	0.684 ppm
2019-06-04	5701-006-0905	0.726 ppm
2019-06-04	5701-800-0950	0.710 ppm
2019-07-02	5701-801-0905	0.707 ppm
2019-07-02	5701-802-1035	0.525 ppm
2019-07-16	5701-006-0739	0.807 ppm
2019-08-07	5701-006-0910	0.660 ppm
2019-08-07	5701-800-0935	0.668 ppm
2019-09-03	5701-006-0825	0.631 ppm
2019-09-03	5701-801-1010	0.625 ppm
2019-09-03	5701-802-1200	0.498 ppm
2019-10-08	5701-006-0920	0.666 ppm
2019-10-08	5701-800-0937	0.650 ppm
2019-11-12	5701-006-0925	0.593 ppm
2019-11-12	5701-801-1010	0.705 ppm
2019-11-12	5701-802-1155	0.650 ppm
2019-12-03	5701-006-0850	0.798 ppm
2019-12-03	5701-800-1010	0.642 ppm