EWG's Tap Water Database — 2021 UPDATE



Purcellville, Town of

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
20140.853 ppm1614ND - 1.69 ppm
20150.768 ppm14140.550 ppm - 1.09 ppm
20160.639 ppm14140.540 ppm - 0.750 ppm
20170.566 ppm1615ND - 0.810 ppm
20180.630 ppm220.540 ppm - 0.720 ppm
20190.197 ppm31ND - 0.590 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
2014-01-15E1312083480.880 ppm
2014-02-26E1312083311.69 ppm
2014-02-26E1312083460.890 ppm
2014-03-18E1312083470.830 ppm
2014-04-10E1403041760.600 ppm
2014-05-20E1403041780.920 ppm
2014-06-10E1403041770.560 ppm
2014-06-26E1403041791.46 ppm
2014-07-08E1406066980.840 ppm
2014-08-21E1406066991.19 ppm
2014-09-10E1406066970.970 ppm
2014-10-21E1409043361.27 ppm
2014-11-18E1409043370.720 ppm
2014-12-16E1409043380.830 ppm
2015-01-20VA010-DCLS0.790 ppm
2015-02-18VA010-DCLS0.860 ppm
2015-03-26VA010-DCLS1.09 ppm
2015-03-26VA010-DCLS0.870 ppm
2015-04-15VA010-DCLS0.840 ppm
2015-05-21VA010-DCLS0.780 ppm
2015-05-21VA010-DCLS0.780 ppm
2015-06-10VA010-DCLS0.580 ppm
2015-07-23VA010-DCLS0.740 ppm
2015-08-18VA010-DCLS0.550 ppm
2015-09-09VA010-DCLS0.850 ppm
2015-10-19VA010-DCLS0.740 ppm
2015-11-17VA010-DCLS0.700 ppm
2015-12-15VA010-DCLS0.580 ppm
2016-01-20E1512059720.610 ppm
2016-02-24E1512059700.620 ppm
2016-03-22E1512059710.700 ppm
2016-04-20E1603057490.670 ppm
2016-05-11E1603057480.620 ppm
2016-06-13E1603057470.680 ppm
2016-06-15E1603057620.750 ppm
2016-07-12E1607003450.540 ppm
2016-08-23E1607003430.560 ppm
2016-09-13E1607003440.630 ppm
2016-10-05E1608054670.540 ppm
2016-11-02E1608054600.680 ppm
2016-11-07E1608054690.690 ppm
2016-12-06E1608054680.650 ppm
2017-01-12E1612013310.760 ppm
2017-02-07E1612013340.720 ppm
2017-02-14E1612013290.630 ppm
2017-03-08E1612013300.680 ppm
2017-04-18E1703004330.550 ppm
2017-05-16E1703004320.560 ppm
2017-05-23E1703004380.570 ppm
2017-05-23E1703004420.810 ppm
2017-06-13E1703004340.500 ppm
2017-07-18E1705040420.570 ppm
2017-08-15E1705040410.620 ppm
2017-09-13E1705040400.600 ppm
2017-10-17E1709019690.580 ppm
2017-11-16E1709019680.470 ppm
2017-12-04E1709019700.430 ppm
2018-02-27E1801003400.720 ppm
2018-05-23E1803038570.540 ppm
2019-05-29E1903048510.590 ppm