Menu

EWG's Tap Water Database — 2019 UPDATE

Donate

Fluoride

Hilo

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.

 

25

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND40ND
20130.0550 ppm41ND - 0.220 ppm
20140.0500 ppm41ND - 0.200 ppm
20150.110 ppm42ND - 0.240 ppm
20160.0575 ppm41ND - 0.230 ppm
20170.0360 ppm51ND - 0.180 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
2012-01-10P0112062ND
2012-01-10P0112063ND
2012-01-10P0112064ND
2012-01-10P0112065ND
2013-03-05C13-03-00290.220 ppm
2013-03-05C13-03-0028ND
2013-03-05C13-03-0027ND
2013-03-05C13-03-0026ND
2014-01-22C14-01-0014ND
2014-01-22C14-01-0015ND
2014-01-22C14-01-00160.200 ppm
2014-01-22C14-01-0017ND
2015-02-04C15-02-00330.240 ppm
2015-02-04C15-02-0032ND
2015-02-04C15-02-00310.200 ppm
2015-02-04C15-02-0030ND
2016-03-22ND
2016-03-22ND
2016-03-220.230 ppm
2016-03-22ND
2017-03-14ND
2017-03-14ND
2017-03-14ND
2017-03-14ND
2017-05-090.180 ppm