EWG's Tap Water Database — 2019 UPDATE



Choice Water Supply Corporation

Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20130.0413 ppm220.0290 ppm - 0.0535 ppm
20140.0415 ppm220.0315 ppm - 0.0515 ppm
20150.00875 ppm21ND - 0.0175 ppm
20160.0468 ppm220.0445 ppm - 0.0490 ppm
20170.0484 ppm220.0163 ppm - 0.0805 ppm

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.

EPA Maximum Contaminant
Level (MCL) 10 ppm

The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.

ppm = parts per million

All test results

Date Lab ID Result
2013-08-13Q13053880060.0290 ppm
2013-08-13Q13053880030.0535 ppm
2014-02-10Q14039370010.0315 ppm
2014-09-02Q14409660030.0515 ppm
2015-07-30Q15297160070.0175 ppm
2016-09-13Q16371450080.0445 ppm
2016-09-13Q16371450070.0490 ppm
2017-11-03Q17568230040.0163 ppm
2017-11-03Q17568230030.0805 ppm