EWG's Tap Water Database — 2019 UPDATE



City of Surprise - Mountain Vista

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
20121.02 ppm16160.590 ppm - 1.53 ppm
20130.945 ppm16160.610 ppm - 1.50 ppm
20141.04 ppm15150.620 ppm - 1.61 ppm
20151.01 ppm15150.620 ppm - 1.52 ppm
20161.04 ppm17170.750 ppm - 1.49 ppm
20170.993 ppm1615ND - 1.53 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
2012-01-262012012-04I0.910 ppm
2012-01-262012012-03I1.51 ppm
2012-01-262012012-02I0.890 ppm
2012-01-262012012-01I0.600 ppm
2012-04-252042001-010.590 ppm
2012-04-252042000-011.51 ppm
2012-04-252041999-011.19 ppm
2012-04-252041994-011.09 ppm
2012-08-152081291-01I0.600 ppm
2012-08-152081287-01I1.53 ppm
2012-08-162081359-01I1.000 ppm
2012-09-042090143-01I0.920 ppm
2012-11-142111028-011.52 ppm
2012-11-142111027-010.610 ppm
2012-11-142111026-010.980 ppm
2012-11-142111024-010.840 ppm
2013-01-233011767-04I1.08 ppm
2013-01-233011767-03I1.09 ppm
2013-01-233011767-020I0.720 ppm
2013-01-233011767-01I0.620 ppm
2013-04-243041985-010.950 ppm
2013-04-243041986-010.910 ppm
2013-04-243041989-010.610 ppm
2013-04-243041987-011.03 ppm
2013-07-163071369-010.950 ppm
2013-07-163071367-01I1.48 ppm
2013-07-163071366-01I0.710 ppm
2013-07-163071362-01I0.640 ppm
2013-10-173101633-01I0.630 ppm
2013-10-173101632-01I1.18 ppm
2013-10-173101631-01I1.50 ppm
2013-10-173101630-01I1.02 ppm
2014-01-224011817-02I0.900 ppm
2014-01-224011817-01I0.620 ppm
2014-01-224011817-03I1.48 ppm
2014-01-224011817-04I1.10 ppm
2014-04-224041931-01I1.12 ppm
2014-04-224041930-01I1.39 ppm
2014-04-224041927-01I0.640 ppm
2014-07-304072667-011.11 ppm
2014-07-304072665-011.56 ppm
2014-07-304072658-010.890 ppm
2014-07-304072656-010.660 ppm
2014-10-284102394-011.61 ppm
2014-10-284102393-010.780 ppm
2014-10-284102387-01I0.990 ppm
2014-10-294102474-01I0.690 ppm
2015-01-215011694-04I1.06 ppm
2015-01-215011694-03I1.47 ppm
2015-01-215011694-02I0.900 ppm
2015-01-215011694-01I0.620 ppm
2015-04-205041746-01I0.740 ppm
2015-04-205041743-010.630 ppm
2015-04-205041742-01I0.980 ppm
2015-04-205041741-01I1.52 ppm
2015-07-285072565-01I0.770 ppm
2015-07-285072564-01I1.05 ppm
2015-07-29507268-011.08 ppm
2015-07-295072676-01I1.52 ppm
2015-10-125101379-01I0.780 ppm
2015-10-125101373-01I0.860 ppm
2015-10-125101369-01I1.10 ppm
2016-01-256012035-04TT1.10 ppm
2016-01-256012035-03TT1.37 ppm
2016-01-256012035-03I1.37 ppm
2016-01-256012035-02TT0.750 ppm
2016-01-256012035-01TT0.800 ppm
2016-04-266042222-01I1.000 ppm
2016-04-266042223-01I1.02 ppm
2016-04-266042227-01I0.760 ppm
2016-04-266042226-01I1.03 ppm
2016-07-266072329-011.05 ppm
2016-07-266072325-010.760 ppm
2016-07-266072323-010.980 ppm
2016-07-266072321-01I1.48 ppm
2016-10-246102137-011.11 ppm
2016-10-246102135-011.49 ppm
2016-10-246102133-01I0.840 ppm
2016-10-246102131-01I0.760 ppm
2017-01-307012591-02C0.880 ppm
2017-01-307012591-010.470 ppm
2017-01-307012591-03C1.51 ppm
2017-01-307012591-04C1.05 ppm
2017-04-207041996-01IOC0.600 ppm
2017-04-207041995-01IOC1.24 ppm
2017-04-207041987-01IOC1.52 ppm
2017-07-197071806-01IOC0.610 ppm
2017-07-197071805-01IOC0.830 ppm
2017-07-197071804-01IOC1.48 ppm
2017-07-197071802-01IOC1.53 ppm
2017-10-117101207-01 IOC0.590 ppm
2017-10-117101207-04 IOC0.910 ppm
2017-10-117101207-03 IOC1.47 ppm
2017-10-117101207-02 IOC1.20 ppm