EWG's Tap Water Database — 2019 UPDATE



Lee County WSC

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
20120.130 ppm110.130 ppm
20130.396 ppm440.180 ppm - 0.700 ppm
20140.280 ppm220.160 ppm - 0.400 ppm
20150.110 ppm110.110 ppm
20160.543 ppm440.240 ppm - 0.740 ppm
20170.537 ppm330.160 ppm - 1.05 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
2012-01-11AB774060.130 ppm
2013-01-3113020400050.700 ppm
2013-01-3113020400040.180 ppm
2013-10-14Q13088540280.182 ppm
2013-10-14Q13088540160.520 ppm
2014-02-25AC443760.400 ppm
2014-02-25AC443750.160 ppm
2015-03-04AC827820.110 ppm
2016-01-27AD202720.680 ppm
2016-01-27AD202710.240 ppm
2016-04-12AD327050.740 ppm
2016-04-12AD327020.510 ppm
2017-01-30AD674110.400 ppm
2017-05-04AD826030.160 ppm
2017-07-24AD902451.05 ppm