EWG's Tap Water Database — 2021 UPDATE



Sardis Water Association

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
20140.593 ppm43ND - 1.03 ppm
20150.960 ppm22220.610 ppm - 1.50 ppm
20160.914 ppm24240.550 ppm - 1.06 ppm
20170.818 ppm23230.490 ppm - 0.980 ppm
20181.05 ppm21210.730 ppm - 1.86 ppm
20190.870 ppm22220.480 ppm - 2.56 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
2014-04-021409300191.03 ppm
2014-12-30Y1501300020.310 ppm
2014-12-30Y1501300011.03 ppm
2015-01-27Y1503300160.930 ppm
2015-01-27Y1503300150.850 ppm
2015-02-25Y1506100170.610 ppm
2015-02-25Y1506100181.02 ppm
2015-03-25Y1508900131.000 ppm
2015-03-25Y1508900140.670 ppm
2015-04-23Y1511400251.11 ppm
2015-05-13Y1513400351.07 ppm
2015-05-13Y1513400341.000 ppm
2015-06-10Y1516700030.840 ppm
2015-06-10Y1516700021.000 ppm
2015-07-14Y1520200150.950 ppm
2015-07-14Y1520200160.970 ppm
2015-08-12Y1522600671.50 ppm
2015-08-12Y1522600751.02 ppm
2015-09-15Y1525800360.850 ppm
2015-09-15Y1525800370.940 ppm
2015-10-12Y1528900720.930 ppm
2015-10-12Y1528900730.970 ppm
2015-11-11Y1532000260.860 ppm
2015-12-16Y1535200401.01 ppm
2015-12-22Y1535700111.03 ppm
2016-01-05Y1600800400.830 ppm
2016-01-05Y1600800310.960 ppm
2016-02-11Y1604700370.990 ppm
2016-02-11Y1604700380.900 ppm
2016-03-15Y1608100160.970 ppm
2016-03-18Y1608100150.920 ppm
2016-04-14Y1610600560.840 ppm
2016-04-14Y1610600570.940 ppm
2016-05-12Y1614400170.980 ppm
2016-05-12Y1614400180.980 ppm
2016-06-08Y1617900061.000 ppm
2016-06-08Y1617900071.000 ppm
2016-07-12Y1620000050.910 ppm
2016-07-12Y1620000060.960 ppm
2016-08-12Y1623500320.960 ppm
2016-08-12Y1623500330.940 ppm
2016-09-13Y1626400020.950 ppm
2016-09-13Y1626400031.000 ppm
2016-10-11Y1628800251.06 ppm
2016-10-11Y1628800261.03 ppm
2016-11-22Y1632800070.620 ppm
2016-11-22Y1632800100.830 ppm
2016-12-14Y1635000260.820 ppm
2016-12-14Y1635000270.550 ppm
2017-01-11Y1701100150.590 ppm
2017-01-11Y1701100160.810 ppm
2017-02-13Y1704600300.950 ppm
2017-02-13Y1704600310.730 ppm
2017-03-15Y1707900340.900 ppm
2017-03-15Y1707900350.960 ppm
2017-04-04Y1709600060.490 ppm
2017-04-12Y1710700310.930 ppm
2017-05-15Y1713800010.780 ppm
2017-05-31Y1715600080.960 ppm
2017-05-31Y1715600090.880 ppm
2017-06-13Y1717000080.980 ppm
2017-06-13Y1717000090.660 ppm
2017-07-11Y1719800160.670 ppm
2017-07-11Y1719800170.900 ppm
2017-08-08Y1722600270.760 ppm
2017-08-08Y1722600280.700 ppm
2017-09-07Y1725400390.800 ppm
2017-10-09Y1728900010.830 ppm
2017-11-06Y1731700270.820 ppm
2017-11-28Y1733800140.940 ppm
2017-12-06Y1734500510.960 ppm
2017-12-06Y1734500520.820 ppm
2018-01-15Y1801800521.05 ppm
2018-01-15Y1801800530.970 ppm
2018-02-15Y1805300191.86 ppm
2018-02-15Y1805300181.84 ppm
2018-03-13Y1807800100.990 ppm
2018-04-17Y1811300110.900 ppm
2018-05-08Y1813400210.980 ppm
2018-05-08Y1813400220.840 ppm
2018-06-15Y1816900311.48 ppm
2018-06-15Y1816900291.07 ppm
2018-07-11Y1819700300.900 ppm
2018-07-11Y1819700290.940 ppm
2018-08-13Y1823200130.940 ppm
2018-08-13Y1823200141.13 ppm
2018-09-13Y1826100270.840 ppm
2018-09-13Y1826100260.920 ppm
2018-10-08Y1828900150.820 ppm
2018-11-12Y1832400070.840 ppm
2018-11-12Y1832400080.730 ppm
2018-12-21Y1836000450.920 ppm
2018-12-21Y1836000461.03 ppm
2019-01-11Y1901400520.920 ppm
2019-01-11Y1901400530.940 ppm
2019-02-14Y1905000570.480 ppm
2019-02-14Y1905000560.930 ppm
2019-03-15Y1907700420.950 ppm
2019-03-15Y1907700430.540 ppm
2019-04-10Y1910500190.860 ppm
2019-05-20Y1915300130.790 ppm
2019-05-20Y1915300140.550 ppm
2019-06-25Y1918200082.56 ppm
2019-06-25Y1918200071.32 ppm
2019-07-12Y1919600450.740 ppm
2019-07-12Y1919600440.710 ppm
2019-08-13Y1923200120.610 ppm
2019-08-13Y1923200110.920 ppm
2019-09-10Y1925300310.540 ppm
2019-09-10Y1925300320.900 ppm
2019-10-01Y1928700130.660 ppm
2019-10-11Y1928800650.600 ppm
2019-10-11Y1928800640.920 ppm
2019-11-14Y1932200450.840 ppm
2019-12-03Y1934300220.870 ppm