Fluoride
City of Durango
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 | 0.947 ppm | 2 | 2 | 0.947 ppm |
2015 | 0.692 ppm | 13 | 13 | 0.610 ppm - 0.790 ppm |
2016 | 0.684 ppm | 4 | 4 | 0.640 ppm - 0.750 ppm |
2017 | 0.663 ppm | 1 | 1 | 0.663 ppm |
2018 | 0.668 ppm | 3 | 3 | 0.648 ppm - 0.700 ppm |
2019 | 0.645 ppm | 7 | 7 | 0.623 ppm - 0.707 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 |
---|---|
2014-05-14 | 0.947 ppm |
2014-05-14 | 0.947 ppm |
2015-06-18 | 0.710 ppm |
2015-06-18 | 0.710 ppm |
2015-08-19 | 0.790 ppm |
2015-08-26 | 0.620 ppm |
2015-09-02 | 0.700 ppm |
2015-09-09 | 0.760 ppm |
2015-09-16 | 0.700 ppm |
2015-09-23 | 0.650 ppm |
2015-09-30 | 0.640 ppm |
2015-10-07 | 0.680 ppm |
2015-10-15 | 0.610 ppm |
2015-10-28 | 0.680 ppm |
2015-11-18 | 0.740 ppm |
2016-01-06 | 0.750 ppm |
2016-03-17 | 0.640 ppm |
2016-04-02 | 0.660 ppm |
2016-06-14 | 0.686 ppm |
2017-06-13 | 0.663 ppm |
2018-06-11 | 0.700 ppm |
2018-06-11 | 0.655 ppm |
2018-12-03 | 0.648 ppm |
2019-02-01 | 0.631 ppm |
2019-03-03 | 0.660 ppm |
2019-04-01 | 0.629 ppm |
2019-06-01 | 0.637 ppm |
2019-07-01 | 0.626 ppm |
2019-10-01 | 0.707 ppm |
2019-11-03 | 0.623 ppm |