Fluoride
Portland Water District - Greater Portland
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 | 0.674 ppm | 13 | 13 | 0.550 ppm - 0.760 ppm |
2015 | 0.672 ppm | 13 | 13 | 0.640 ppm - 0.710 ppm |
2016 | 0.699 ppm | 13 | 13 | 0.630 ppm - 0.770 ppm |
2017 | 0.662 ppm | 13 | 13 | 0.500 ppm - 0.720 ppm |
2018 | 0.642 ppm | 13 | 13 | 0.480 ppm - 0.720 ppm |
2019 | 0.663 ppm | 13 | 13 | 0.530 ppm - 0.730 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 | 0.720 ppm | |
2014-02-03 | 0.600 ppm | |
2014-03-03 | 0.730 ppm | |
2014-04-07 | 0.610 ppm | |
2014-05-05 | 0.620 ppm | |
2014-06-02 | 0.700 ppm | |
2014-06-04 | 0.550 ppm | |
2014-07-07 | 0.750 ppm | |
2014-08-04 | 0.740 ppm | |
2014-09-02 | 0.600 ppm | |
2014-10-06 | 0.760 ppm | |
2014-11-03 | 0.740 ppm | |
2014-12-01 | 0.640 ppm | |
2015-01-05 | W-150105-0022 | 0.690 ppm |
2015-02-02 | W-150202-0020 | 0.640 ppm |
2015-03-02 | W-150302-0019 | 0.670 ppm |
2015-04-06 | W-150406-0018 | 0.640 ppm |
2015-05-04 | W-150504-0020 | 0.650 ppm |
2015-06-01 | W-150601-0018 | 0.660 ppm |
2015-06-02 | 144058.01-TE6 | 0.640 ppm |
2015-07-06 | W-150706-0018 | 0.660 ppm |
2015-08-03 | W-150803-0020 | 0.690 ppm |
2015-09-08 | W-150908-0029 | 0.680 ppm |
2015-10-05 | W-151005-0018 | 0.710 ppm |
2015-11-02 | W-151102-0017 | 0.710 ppm |
2015-12-07 | W-151207-0017 | 0.700 ppm |
2016-01-04 | W-160104-0019 | 0.690 ppm |
2016-02-01 | W-160201-0017 | 0.690 ppm |
2016-03-07 | W-160307-0017 | 0.680 ppm |
2016-04-04 | W-160404-0019 | 0.710 ppm |
2016-05-02 | W-160502-0017 | 0.710 ppm |
2016-06-06 | W-160606-0017 | 0.690 ppm |
2016-06-07 | 156908.01-TE6 | 0.630 ppm |
2016-07-05 | W-160705-0034 | 0.700 ppm |
2016-08-01 | W-160801-0019 | 0.750 ppm |
2016-09-06 | W-160906-0031 | 0.770 ppm |
2016-10-03 | W-161003-0016 | 0.690 ppm |
2016-11-07 | W-161107-0016 | 0.660 ppm |
2016-12-05 | W-161205-0018 | 0.720 ppm |
2017-01-03 | W-170103-0033 | 0.720 ppm |
2017-02-06 | W-170206-0016 | 0.690 ppm |
2017-03-06 | W-170306-0016 | 0.700 ppm |
2017-04-03 | W-170403-0018 | 0.690 ppm |
2017-05-01 | W-170501-0016 | 0.680 ppm |
2017-06-05 | W-170605-0016 | 0.670 ppm |
2017-06-28 | 170385.01-TE6 | 0.500 ppm |
2017-07-05 | W-170705-0036 | 0.680 ppm |
2017-08-07 | W-170807-0017 | 0.640 ppm |
2017-09-05 | W-170905-0036 | 0.630 ppm |
2017-10-02 | W-171002-0014 | 0.660 ppm |
2017-11-06 | W-171106-0014 | 0.660 ppm |
2017-12-04 | W-171204-0016 | 0.680 ppm |
2018-01-02 | W-180102-0032 | 0.720 ppm |
2018-02-06 | W-180206-0033 | 0.680 ppm |
2018-03-05 | W-180305-0021 | 0.670 ppm |
2018-04-02 | W-180402-0019 | 0.690 ppm |
2018-05-07 | W-180507-0020 | 0.650 ppm |
2018-06-04 | W-180604-0020 | 0.660 ppm |
2018-07-02 | W-180702-0022 | 0.620 ppm |
2018-07-10 | 1807-01040-001 | 0.480 ppm |
2018-08-06 | W-180806-0021 | 0.600 ppm |
2018-09-04 | W-180904-0033 | 0.600 ppm |
2018-10-01 | W-181001-0021 | 0.630 ppm |
2018-11-05 | W-181105-0021 | 0.630 ppm |
2018-12-03 | W-181203-0020 | 0.720 ppm |
2019-01-07 | W-190107-0020 | 0.710 ppm |
2019-02-04 | W-190204-0018 | 0.710 ppm |
2019-03-04 | W-190304-0020 | 0.620 ppm |
2019-04-01 | W-190401-0018 | 0.660 ppm |
2019-05-06 | W-190506-0018 | 0.650 ppm |
2019-06-03 | W-190603-0020 | 0.610 ppm |
2019-06-04 | 1906-00591-001 | 0.530 ppm |
2019-07-01 | W-190701-0018 | 0.620 ppm |
2019-08-05 | W-190805-0018 | 0.710 ppm |
2019-09-03 | W-190903-0034 | 0.690 ppm |
2019-10-07 | W-191007-0018 | 0.660 ppm |
2019-11-04 | W-191104-0020 | 0.720 ppm |
2019-12-02 | W-191202-0018 | 0.730 ppm |