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EWG's Tap Water Database — 2019 UPDATE

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Fluoride

Los Angeles County WW District 4 & 34-Lancaster

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.

 

53

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.335 ppm440.329 ppm - 0.341 ppm
20130.339 ppm20200.152 ppm - 0.656 ppm
20140.367 ppm330.186 ppm - 0.526 ppm
20150.338 ppm330.314 ppm - 0.365 ppm
20160.341 ppm17170.151 ppm - 0.672 ppm
20170.352 ppm660.150 ppm - 0.480 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
2012-01-245442-053-09030.336 ppm
2012-01-245442-054-09370.341 ppm
2012-04-125442-054-10150.329 ppm
2012-11-145442-037-11570.334 ppm
2013-03-115442-062-11300.244 ppm
2013-03-115442-011-09310.312 ppm
2013-03-115442-016-11400.401 ppm
2013-03-115442-023-10450.425 ppm
2013-03-115442-028-12050.519 ppm
2013-03-125442-036-11060.231 ppm
2013-03-135442-035-11590.194 ppm
2013-03-135442-035-08520.359 ppm
2013-03-195442-026-09250.463 ppm
2013-03-195442-002-11350.329 ppm
2013-04-035442-063-08350.384 ppm
2013-04-095442-070-09450.241 ppm
2013-05-215442-040-09080.196 ppm
2013-06-045442-041-09100.371 ppm
2013-06-045442-048-09340.403 ppm
2013-06-125442-095-08590.292 ppm
2013-07-165442-045-10500.444 ppm
2013-07-175442-067-10500.656 ppm
2013-07-235442-071-10470.167 ppm
2013-07-245442-069-10020.152 ppm
2014-03-265442-055-10340.389 ppm
2014-06-265442-093-08500.526 ppm
2014-08-255442-094-10050.186 ppm
2015-01-285442-053-09150.314 ppm
2015-04-135442-054-09400.365 ppm
2015-08-185442-037-09300.336 ppm
2016-01-195442-035-09500.279 ppm
2016-01-195442-040-09450.233 ppm
2016-01-255442-062-09300.316 ppm
2016-01-255442-048-09400.461 ppm
2016-01-255442-028-08400.453 ppm
2016-02-095442-016-10280.534 ppm
2016-02-095442-068-10250.151 ppm
2016-02-095442-070-11100.247 ppm
2016-02-095442-069-10100.179 ppm
2016-02-105442-071-11250.349 ppm
2016-03-095442-023-10410.380 ppm
2016-03-285442-067-08560.672 ppm
2016-03-285442-011-11380.365 ppm
2016-04-205442-041-09340.357 ppm
2016-04-205442-026-10160.381 ppm
2016-06-085442-036-09450.228 ppm
2016-06-275442-095-10500.216 ppm
2017-11-219590-063-10100.390 ppm
2017-11-219590-055-09400.350 ppm
2017-11-219590-045-09350.390 ppm
2017-12-279590-063-10100.350 ppm
2017-12-279590-094-09100.150 ppm
2017-12-279590-093-11150.480 ppm