EWG's Tap Water Database



Brinkley Waterworks

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
20101.06 ppm12120.820 ppm - 1.63 ppm
20111.07 ppm12120.940 ppm - 1.15 ppm
20120.951 ppm13130.750 ppm - 1.39 ppm
20130.866 ppm10100.720 ppm - 0.990 ppm
20140.678 ppm990.420 ppm - 1.17 ppm
20150.766 ppm12120.670 ppm - 0.840 ppm

ppm = parts per million.

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 4 ppm

The enforceable federal standard that defines the highest level of a contaminant allowed in drinking water.

ppm = parts per million.

EPA Maximum Contaminant
Level Goal (MCLG)4 ppm

A non-enforceable federal health guideline. For cancer-causing chemicals, these health goals are typically set to zero.

ppm = parts per million.

All test results

Date Lab ID Result
2010-01-041001100331.11 ppm
2010-02-021004200310.820 ppm
2010-03-021006700310.880 ppm
2010-04-011010200211.12 ppm
2010-05-061013000101.63 ppm
2010-06-011015800081.10 ppm
2010-07-071019300160.980 ppm
2010-08-031022100321.000 ppm
2010-09-021025000031.06 ppm
2010-10-051028400140.980 ppm
2010-11-011031200180.990 ppm
2010-12-011034700031.02 ppm
2011-01-041101200131.14 ppm
2011-02-041104600221.10 ppm
2011-03-041107300171.02 ppm
2011-04-051110100261.12 ppm
2011-05-041112900231.11 ppm
2011-06-011116500021.05 ppm
2011-07-111119900420.940 ppm
2011-08-111122700371.01 ppm
2011-09-011125000061.04 ppm
2011-10-031128300021.15 ppm
2011-11-031131800091.04 ppm
2011-12-061134600271.08 ppm
2012-01-031201000440.920 ppm
2012-02-011204500081.39 ppm
2012-03-011207300010.980 ppm
2012-04-031210000240.980 ppm
2012-05-031213500010.920 ppm
2012-06-051216300200.920 ppm
2012-07-021219100150.870 ppm
2012-08-011222100260.950 ppm
2012-09-051225400300.750 ppm
2012-09-101225500030.790 ppm
2012-10-011228200140.960 ppm
2012-11-011231400021.000 ppm
2012-12-031234500250.930 ppm
2013-01-021301400040.940 ppm
2013-02-051304200290.950 ppm
2013-04-011309800120.920 ppm
2013-05-021312700220.990 ppm
2013-06-031316100250.860 ppm
2013-07-011319000090.830 ppm
2013-08-141323200280.740 ppm
2013-10-011328100270.720 ppm
2013-11-011331000170.780 ppm
2013-12-031334400200.930 ppm
2014-01-031400800140.700 ppm
2014-02-031404100100.540 ppm
2014-03-061407600140.730 ppm
2014-04-011409700110.500 ppm
2014-05-011413200101.17 ppm
2014-06-021416000010.540 ppm
2014-07-011418800100.420 ppm
2014-08-071422400080.710 ppm
2014-12-01Y1434200130.790 ppm
2015-01-05Y1501300350.770 ppm
2015-02-02Y1504000160.710 ppm
2015-03-02Y1506900300.720 ppm
2015-04-08Y1511100190.750 ppm
2015-05-05Y1513400300.740 ppm
2015-06-03Y1516100160.820 ppm
2015-07-01Y1519500070.780 ppm
2015-08-03Y1521800260.790 ppm
2015-08-25Y1523800130.670 ppm
2015-09-01Y1525100240.770 ppm
2015-10-02Y1528500220.840 ppm
2015-12-02Y1534800010.830 ppm