EWG's Tap Water Database — 2021 UPDATE



Global Water - Santa Cruz Water Company

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
20141.57 ppm12120.980 ppm - 1.90 ppm
20151.64 ppm14141.10 ppm - 1.90 ppm
20161.82 ppm12121.30 ppm - 2.10 ppm
20171.83 ppm1211ND - 2.20 ppm
20181.35 ppm17170.600 ppm - 2.20 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
2014-01-06550-17068-11.30 ppm
2014-02-03550-18834-1I1.30 ppm
2014-03-06550-20760-1I0.980 ppm
2014-04-02550-22240-11.40 ppm
2014-05-05550-24014-11.60 ppm
2014-06-02550-25442-11.70 ppm
2014-07-07550-27410-2I1.80 ppm
2014-08-04550-29108-1I1.70 ppm
2014-09-04550-31024-4I1.90 ppm
2014-10-06550-32711-11.50 ppm
2014-11-03550-34370-1I1.80 ppm
2014-12-01550-35944-1I1.90 ppm
2015-01-05550-37804-11.40 ppm
2015-01-12550-38232-1I1.40 ppm
2015-02-02550-39355-41.30 ppm
2015-03-11550-41436-1I1.40 ppm
2015-04-06550-42710-11.80 ppm
2015-05-04550-44184-11.90 ppm
2015-06-02550-45659-11.90 ppm
2015-07-06550-47300-1I1.80 ppm
2015-08-25550-50079-41.80 ppm
2015-09-17550-51388-1I1.90 ppm
2015-10-21550-53091-11.80 ppm
2015-10-21550-53084-11.80 ppm
2015-11-19550-54683-11.70 ppm
2015-12-03550-55224-1I1.10 ppm
2016-01-06550-56699-11.30 ppm
2016-02-04550-58359-1I1.30 ppm
2016-03-02550-59644-1I1.70 ppm
2016-04-19550-62104-1I2.00 ppm
2016-05-11550-63303-11.80 ppm
2016-06-15550-64925-1I2.00 ppm
2016-07-21550-66735-1I2.00 ppm
2016-08-22550-68428-12.00 ppm
2016-09-08550-69235-1I2.00 ppm
2016-10-18550-71376-12.00 ppm
2016-11-03550-72325-12.10 ppm
2016-12-20550-74712-1I1.60 ppm
2017-01-12550-75775-1I1.70 ppm
2017-02-16550-77760-11.80 ppm
2017-03-09550-78968-1I1.60 ppm
2017-05-16550-82890-1IOC2.00 ppm
2017-06-15550-84530-12.10 ppm
2017-07-13550-85947-12.20 ppm
2017-08-10550-87790-1 IOC2.10 ppm
2017-09-13550-89708-12.20 ppm
2017-10-19550-91759-12.10 ppm
2017-11-16550-93318-12.20 ppm
2017-12-14550-94792-11.90 ppm
2018-01-11550-96131-11.60 ppm
2018-02-08550-97680-1IOC1.80 ppm
2018-03-01550-98738-1 IOC1.90 ppm
2018-04-18550-101447-12.10 ppm
2018-05-10550-102718-12.20 ppm
2018-06-21550-104789-1 IOC2.10 ppm
2018-07-23550-106542-1 IOC1.90 ppm
2018-08-02550-107136-2 IOC0.690 ppm
2018-08-02550-107136-1 IOC1.80 ppm
2018-09-06550-109241-2 IOC0.720 ppm
2018-09-06550-109241-1 IOC1.10 ppm
2018-10-04550-110930-20.710 ppm
2018-10-04550-110930-10.720 ppm
2018-11-01550-112704-2 IOC0.720 ppm
2018-11-01550-112704-1 IOC1.10 ppm
2018-12-06550-114480-20.600 ppm
2018-12-06550-114480-11.20 ppm
2019-01-10550-116176-20.760 ppm
2019-01-10550-116176-11.10 ppm
2019-02-07550-117598-2 IOC0.600 ppm
2019-02-07550-117598-1 IOC1.20 ppm
2019-03-07550-119067-2 IOC0.600 ppm
2019-03-07550-119067-1 IOC1.40 ppm
2019-04-04550-120507-2 IOC0.590 ppm
2019-04-04550-120507-1 IOC1.50 ppm
2019-05-02550-122138-1 IOC1.70 ppm
2019-05-02550-122128-2 IOC0.820 ppm
2019-06-06550-123978-2 IOC0.580 ppm
2019-06-06550-123978-1 IOC1.80 ppm
2019-07-11550-125912-2 IOC0.770 ppm
2019-07-11550-125912-1 IOC1.90 ppm
2019-08-01550-127100-2 IOC0.720 ppm
2019-08-01550-127100-1 IOC1.30 ppm
2019-09-05550-129140-2 IOC0.690 ppm
2019-09-05550-129140-1 IOC1.60 ppm
2019-10-03550-130764-2 IOC0.750 ppm
2019-10-03550-130764-1 IOC1.60 ppm
2019-11-07550-132911-2 IOC0.720 ppm
2019-11-07550-132911-1 IOC1.20 ppm
2019-12-05550-134356-11.10 ppm
2019-12-05550-134356-20.800 ppm