EWG's Tap Water Database — 2019 UPDATE



Heber Springs Water System

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
20120.794 ppm13130.580 ppm - 0.940 ppm
20130.741 ppm13130.620 ppm - 0.850 ppm
20140.755 ppm13130.640 ppm - 0.920 ppm
20150.805 ppm13130.710 ppm - 0.970 ppm
20160.776 ppm13130.670 ppm - 0.890 ppm
20170.747 ppm13130.660 ppm - 0.820 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
2012-01-031201000190.770 ppm
2012-02-021204500030.940 ppm
2012-03-011207300140.800 ppm
2012-04-021210000250.850 ppm
2012-05-021212800130.830 ppm
2012-06-041216300260.880 ppm
2012-07-021219100170.770 ppm
2012-08-021222100270.580 ppm
2012-09-041225400270.600 ppm
2012-10-031228200230.710 ppm
2012-10-311230600040.910 ppm
2012-11-051231400340.860 ppm
2012-12-031234500240.820 ppm
2013-01-071301400480.720 ppm
2013-02-041304200150.810 ppm
2013-03-041307000280.850 ppm
2013-04-011310600100.660 ppm
2013-05-011312700160.680 ppm
2013-06-031316100160.810 ppm
2013-07-011319000080.750 ppm
2013-08-191322500170.750 ppm
2013-09-031325300150.800 ppm
2013-10-021328100320.750 ppm
2013-10-021327600070.720 ppm
2013-11-041331700010.620 ppm
2013-12-021333800200.710 ppm
2014-01-061401600100.760 ppm
2014-02-031404100180.640 ppm
2014-03-031406900010.830 ppm
2014-04-021410400120.650 ppm
2014-05-011413200040.840 ppm
2014-06-041416700060.720 ppm
2014-07-031419500070.670 ppm
2014-08-051422400020.700 ppm
2014-09-081425800380.800 ppm
2014-10-01Y1427900030.710 ppm
2014-11-03Y1431100330.860 ppm
2014-11-04Y1431000440.710 ppm
2014-12-01Y1434200220.920 ppm
2015-01-05Y1501300340.730 ppm
2015-02-02Y1504000260.820 ppm
2015-03-03Y1506900110.970 ppm
2015-04-01Y1510300240.750 ppm
2015-05-04Y1513400290.790 ppm
2015-06-01Y1515500610.710 ppm
2015-07-01Y1519500090.830 ppm
2015-08-05Y1522600440.800 ppm
2015-09-02Y1525800090.850 ppm
2015-10-02Y1528500040.810 ppm
2015-10-22Y1529500030.820 ppm
2015-11-02Y1531300090.840 ppm
2015-12-02Y1534100190.740 ppm
2016-01-06Y1601200050.810 ppm
2016-02-02Y1604000230.840 ppm
2016-03-01Y1606800050.830 ppm
2016-04-01Y1610400090.890 ppm
2016-05-05Y1613000190.800 ppm
2016-06-02Y1616500030.730 ppm
2016-07-05Y1619300140.710 ppm
2016-08-02Y1622100220.700 ppm
2016-09-02Y1625600070.710 ppm
2016-10-06Y1628800910.800 ppm
2016-10-17Y1629400070.770 ppm
2016-11-03Y1631400250.670 ppm
2016-12-01Y1634200150.830 ppm
2017-01-03Y1701000240.720 ppm
2017-02-14Y1704800220.740 ppm
2017-03-01Y1707200340.810 ppm
2017-04-03Y1710000330.700 ppm
2017-05-01Y1712800210.820 ppm
2017-06-01Y1716300140.820 ppm
2017-07-05Y1719100370.690 ppm
2017-08-01Y1722600090.720 ppm
2017-09-06Y1726100040.660 ppm
2017-10-03Y1728200370.720 ppm
2017-10-24Y1729900010.810 ppm
2017-11-01Y1731000210.730 ppm
2017-12-04Y1734500570.770 ppm