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EWG's Tap Water Database — 2019 UPDATE

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Fluoride

Massachusetts Water Resources Authority (MWRA)

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.

 

48

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.472 ppm86ND - 0.980 ppm
20130.491 ppm87ND - 1.02 ppm
20140.489 ppm87ND - 1.01 ppm
20150.405 ppm84ND - 0.962 ppm
20160.335 ppm84ND - 0.718 ppm
20170.348 ppm84ND - 0.712 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
2012-01-090.980 ppm
2012-01-10ND
2012-04-02ND
2012-04-020.857 ppm
2012-07-090.922 ppm
2012-07-100.0341 ppm
2012-10-010.942 ppm
2012-10-020.0375 ppm
2013-01-070.965 ppm
2013-01-080.0225 ppm
2013-04-011.02 ppm
2013-04-020.0507 ppm
2013-07-09ND
2013-07-090.856 ppm
2013-10-080.0843 ppm
2013-10-080.931 ppm
2014-01-061.01 ppm
2014-01-070.0451 ppm
2014-04-070.0530 ppm
2014-04-070.869 ppm
2014-07-070.925 ppm
2014-07-080.0207 ppm
2014-10-060.992 ppm
2014-10-07ND
2015-01-050.962 ppm
2015-01-06ND
2015-04-060.914 ppm
2015-04-07ND
2015-07-070.668 ppm
2015-07-07ND
2015-10-06ND
2015-10-060.692 ppm
2016-01-05ND
2016-01-050.625 ppm
2016-04-05ND
2016-04-050.682 ppm
2016-07-05ND
2016-07-050.653 ppm
2016-10-040.718 ppm
2016-10-04ND
2017-01-030.693 ppm
2017-01-03ND
2017-04-040.674 ppm
2017-04-04ND
2017-07-11ND
2017-07-110.708 ppm
2017-10-03ND
2017-10-030.712 ppm