Fluoride
Wilmington 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.
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 | 0.649 ppm | 21 | 21 | 0.458 ppm - 0.988 ppm |
| 2015 | 0.632 ppm | 18 | 18 | 0.425 ppm - 0.810 ppm |
| 2016 | 0.725 ppm | 15 | 15 | 0.524 ppm - 1.37 ppm |
| 2017 | 0.756 ppm | 26 | 26 | 0.000822 ppm - 0.954 ppm |
| 2018 | 0.874 ppm | 21 | 20 | ND - 1.20 ppm |
| 2019 | 0.908 ppm | 24 | 24 | 0.649 ppm - 1.40 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 |
|---|---|---|
| 2014-01-15 | L4901341-1 | 0.507 ppm |
| 2014-01-15 | L4901341-2 | 0.731 ppm |
| 2014-02-19 | L4948344-1 | 0.566 ppm |
| 2014-03-14 | L4976286-1 | 0.613 ppm |
| 2014-04-15 | L5015334-1 | 0.596 ppm |
| 2014-04-15 | L5015334-2 | 0.595 ppm |
| 2014-05-15 | L5060576-1 | 0.740 ppm |
| 2014-05-15 | L5060576-2 | 0.566 ppm |
| 2014-06-16 | L5110756-1 | 0.635 ppm |
| 2014-06-16 | L5110756-2 | 0.710 ppm |
| 2014-07-15 | L5162588-1 | 0.988 ppm |
| 2014-07-15 | L5162588-2 | 0.580 ppm |
| 2014-08-15 | L5207030-1 | 0.552 ppm |
| 2014-08-15 | L5207030-2 | 0.483 ppm |
| 2014-09-10 | L5241692-1 | 0.458 ppm |
| 2014-09-10 | L5241692-2 | 0.807 ppm |
| 2014-10-15 | L5287642-1 | 0.764 ppm |
| 2014-11-14 | L5323793-1 | 0.479 ppm |
| 2014-12-15 | L5359295-1 | 0.540 ppm |
| 2014-12-22 | S553973 | 0.790 ppm |
| 2014-12-22 | S553974 | 0.920 ppm |
| 2015-01-15 | L5409548-1 | 0.528 ppm |
| 2015-02-13 | L5453485-1 | 0.425 ppm |
| 2015-02-13 | L5453485-2 | 0.483 ppm |
| 2015-03-16 | L5495176-1 | 0.717 ppm |
| 2015-04-15 | L5536824-1 | 0.565 ppm |
| 2015-04-15 | L5536824-2 | 0.466 ppm |
| 2015-05-15 | L5591174-1 | 0.602 ppm |
| 2015-05-15 | L5591174-2 | 0.713 ppm |
| 2015-06-15 | L5645574-1 | 0.810 ppm |
| 2015-06-15 | L5645574-2 | 0.697 ppm |
| 2015-07-15 | L5709634-1 | 0.716 ppm |
| 2015-07-15 | L5709634-2 | 0.648 ppm |
| 2015-08-14 | L5763826-1 | 0.673 ppm |
| 2015-09-15 | L5816026-1 | 0.673 ppm |
| 2015-10-15 | L5865923-1 | 0.674 ppm |
| 2015-11-16 | L5912491-1 | 0.705 ppm |
| 2015-12-18 | L5964979-1 | 0.672 ppm |
| 2015-12-30 | S659017 | 0.610 ppm |
| 2016-01-15 | L6018767-1 | 0.546 ppm |
| 2016-02-16 | L6073152-1 | 0.524 ppm |
| 2016-03-15 | L6123181-1 | 0.578 ppm |
| 2016-04-15 | L6183086-1 | 0.545 ppm |
| 2016-05-13 | L6248028-1 | 0.760 ppm |
| 2016-07-15 | L6374535-1 | 0.656 ppm |
| 2016-08-15 | L6421565-1 FL | 0.770 ppm |
| 2016-09-15 | L6489770-1 | 0.782 ppm |
| 2016-10-14 | L6510888-1 | 0.831 ppm |
| 2016-11-15 | L6550752-1 | 0.654 ppm |
| 2016-11-30 | L6581348-1 | 0.788 ppm |
| 2016-12-08 | S719707 | 0.770 ppm |
| 2016-12-08 | S719708 | 0.600 ppm |
| 2016-12-15 | L6593079-1 | 0.700 ppm |
| 2016-12-15 | L6593079-2 | 1.37 ppm |
| 2017-01-13 | L6637334-1 | 0.812 ppm |
| 2017-01-13 | L6637334-2 | 0.000822 ppm |
| 2017-02-15 | L6684762-1 | 0.749 ppm |
| 2017-02-15 | L6684762-2 | 0.718 ppm |
| 2017-03-15 | L6734174-1 | 0.911 ppm |
| 2017-03-16 | L6734174-2 | 0.661 ppm |
| 2017-04-13 | L6763081-1 | 0.810 ppm |
| 2017-04-13 | L6763081-2 | 0.811 ppm |
| 2017-05-15 | L6809740-1 | 0.795 ppm |
| 2017-05-15 | L6809740-2 | 0.693 ppm |
| 2017-06-15 | L6859458-1 | 0.954 ppm |
| 2017-06-15 | L6859458-2 | 0.823 ppm |
| 2017-07-14 | L6904364-1 | 0.932 ppm |
| 2017-07-14 | L6904364-2 | 0.885 ppm |
| 2017-08-15 | L6936928-1 | 0.948 ppm |
| 2017-08-15 | L6936928-2 | 0.700 ppm |
| 2017-09-15 | L6952034-1 | 0.768 ppm |
| 2017-09-15 | L6952035-1 | 0.686 ppm |
| 2017-10-13 | L6961066-1 | 0.684 ppm |
| 2017-10-13 | L6961066-2 | 0.616 ppm |
| 2017-11-15 | L6972529-1 | 0.722 ppm |
| 2017-11-15 | L6972529-2 | 0.740 ppm |
| 2017-12-15 | L6984026-1 | 0.860 ppm |
| 2017-12-15 | L6984026-2 | 0.720 ppm |
| 2017-12-27 | S782296 | 0.700 ppm |
| 2017-12-27 | S782297 | 0.950 ppm |
| 2018-01-16 | L6992482-1 | 1.10 ppm |
| 2018-01-16 | L6992482-2 | 1.20 ppm |
| 2018-02-15 | L7001651-1 FL | 1.10 ppm |
| 2018-02-15 | L7001651-2 FL | ND |
| 2018-03-15 | L7010022-1 FL | 0.900 ppm |
| 2018-04-16 | L7017320-1 | 0.950 ppm |
| 2018-05-15 | L7024991-1 | 0.740 ppm |
| 2018-06-15 | L7041390-1 | 0.690 ppm |
| 2018-07-16 | L7050855-1 | 0.890 ppm |
| 2018-08-15 | L7061678-1 | 0.720 ppm |
| 2018-09-14 | L7072412-1 FL | 1.10 ppm |
| 2018-10-15 | L7078453-1 | 0.780 ppm |
| 2018-10-15 | L7078453-2 | 0.800 ppm |
| 2018-11-15 | L7085906-1 | 0.810 ppm |
| 2018-11-15 | L7085906-1 FL | 0.800 ppm |
| 2018-11-15 | L7085906-2 | 1.20 ppm |
| 2018-11-15 | L7085906-2 | 1.20 ppm |
| 2018-12-14 | L7091238-1 | 0.830 ppm |
| 2018-12-14 | L7091238-2 | 0.900 ppm |
| 2018-12-31 | S855897 | 0.645 ppm |
| 2018-12-31 | S855898 | 0.992 ppm |
| 2019-01-15 | L7099911-1 | 0.750 ppm |
| 2019-01-15 | L7099911-2 | 1.000 ppm |
| 2019-04-22 | S881031 | 0.777 ppm |
| 2019-04-22 | S881034 | 0.826 ppm |
| 2019-05-15 | L7123136-1 | 1.30 ppm |
| 2019-05-15 | L7123136-2 | 1.40 ppm |
| 2019-05-15 | S881037 | 0.736 ppm |
| 2019-05-15 | S881040 | 0.671 ppm |
| 2019-06-17 | L7135427-1 | 1.20 ppm |
| 2019-06-17 | L7135427-2 | 1.20 ppm |
| 2019-06-17 | S881035 | 0.850 ppm |
| 2019-06-17 | S881038 | 0.848 ppm |
| 2019-07-22 | S881033 | 1.00 ppm |
| 2019-07-22 | S881036 | 1.03 ppm |
| 2019-08-15 | S881039 | 0.812 ppm |
| 2019-08-15 | S881042 | 0.827 ppm |
| 2019-09-11 | S907483 | 0.943 ppm |
| 2019-09-11 | S907484 | 0.887 ppm |
| 2019-10-15 | 1196173 | 1.000 ppm |
| 2019-10-15 | 1196174 | 0.900 ppm |
| 2019-11-18 | S925489 | 0.673 ppm |
| 2019-11-18 | S925490 | 0.846 ppm |
| 2019-12-16 | S925478 | 0.649 ppm |
| 2019-12-16 | S925481 | 0.678 ppm |