EWG's Tap Water Database — 2019 UPDATE



City of Wichita Falls

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
20120.765 ppm220.680 ppm - 0.850 ppm
20130.610 ppm220.560 ppm - 0.660 ppm
20140.544 ppm440.470 ppm - 0.706 ppm
20150.547 ppm440.466 ppm - 0.640 ppm
20160.646 ppm220.586 ppm - 0.706 ppm
20170.658 ppm220.641 ppm - 0.674 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
2012-03-2712039440010.680 ppm
2012-05-1612056090010.850 ppm
2013-03-261303A430020.660 ppm
2013-03-261303A430010.560 ppm
2014-05-13Q14158160030.706 ppm
2014-08-14Q14367960160.470 ppm
2014-11-12AC717900.500 ppm
2014-11-12AC717910.500 ppm
2015-02-09Q15050190090.514 ppm
2015-02-09Q15050190080.466 ppm
2015-05-11Q15171930030.568 ppm
2015-09-22Q15370190040.640 ppm
2016-02-01Q16041900050.586 ppm
2016-02-01Q16041900040.706 ppm
2017-03-06Q17092270040.641 ppm
2017-08-07Q17330930080.674 ppm