EWG's Tap Water Database — 2021 UPDATE



Jenkins Water System

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 exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20140.440 ppm220.300 ppm - 0.580 ppm
20150.905 ppm220.840 ppm - 0.970 ppm
20160.715 ppm220.700 ppm - 0.730 ppm
20170.540 ppm220.450 ppm - 0.630 ppm
20190.770 ppm220.650 ppm - 0.890 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
2014-03-062014031920010.580 ppm
2014-04-032014048360010.300 ppm
2015-03-122015029920010.840 ppm
2015-04-092015043010010.970 ppm
2016-03-022016030310010.730 ppm
2016-04-062016047890010.700 ppm
2017-03-082017032640010.630 ppm
2017-04-052017049110010.450 ppm
2019-03-05190063140.890 ppm
2019-05-07190129360.650 ppm