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EWG's Tap Water Database — 2021 UPDATE

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Nitrate

Regional Water Authority

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.

MORE ABOUT THIS CONTAMINANT

 

65

Samples

0

Samples exceeding legal limit (MCL)

55

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20141.28 ppm10100.0470 ppm - 3.40 ppm
20151.15 ppm11110.111 ppm - 3.15 ppm
20160.972 ppm119ND - 3.24 ppm
20171.09 ppm11110.0520 ppm - 2.81 ppm
20181.17 ppm11110.114 ppm - 2.97 ppm
20191.33 ppm11110.0200 ppm - 3.72 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
2014-02-25NOX 2003916000.360 ppm
2014-02-25NOX 2003915990.0470 ppm
2014-02-25NOX 2003916530.695 ppm
2014-02-25NOX 2003916200.197 ppm
2014-02-25NOX 2003916192.77 ppm
2014-02-25NOX 2003916183.09 ppm
2014-02-25NOX 2003916171.03 ppm
2014-02-25NOX 2003916163.40 ppm
2014-05-13NOX 2003958550.453 ppm
2014-05-13NOX 2003958600.714 ppm
2015-01-08NOX 2004104330.930 ppm
2015-02-10NOX 2004118592.43 ppm
2015-02-10NOX 2004118620.772 ppm
2015-02-10NOX 2004118600.273 ppm
2015-02-10NOX 2004118450.111 ppm
2015-02-10NOX 2004118463.15 ppm
2015-02-10NOX 2004118630.304 ppm
2015-02-10NOX 2004118760.829 ppm
2015-03-18NOX 2004137132.90 ppm
2015-05-05NOX 2004161680.594 ppm
2015-05-05NOX 2004161750.339 ppm
2016-02-09NOX 2004334150.101 ppm
2016-02-09NOX 200433425ND
2016-02-09NOX 2004333980.198 ppm
2016-02-09NOX 2004333970.0270 ppm
2016-02-09NOX 2004334790.836 ppm
2016-02-09NOX 2004334132.64 ppm
2016-02-09NOX 2004334120.854 ppm
2016-02-09NOX 2004334142.31 ppm
2016-02-09NOX 2004334113.24 ppm
2016-05-12NOX 2004395130.490 ppm
2016-05-12NOX 200439515ND
2017-03-21NOX 2004627392.81 ppm
2017-03-21NOX 2004627770.482 ppm
2017-03-21NOX 2004627430.144 ppm
2017-03-21NOX 2004627570.203 ppm
2017-03-21NOX 2004627560.0520 ppm
2017-03-21NOX 2004627412.79 ppm
2017-03-21NOX 2004627400.741 ppm
2017-03-21NOX 2004627422.67 ppm
2017-03-21NOX 2004627930.667 ppm
2017-06-20NOX 2004698120.840 ppm
2017-06-20NOX 2004698270.632 ppm
2018-03-14NOX 2004898672.47 ppm
2018-03-14NOX 2004898702.70 ppm
2018-03-14NOX 2004898681.04 ppm
2018-03-14NOX 2004898840.114 ppm
2018-03-14NOX 2004898850.270 ppm
2018-03-14NOX 2004898710.388 ppm
2018-03-14NOX 2004899130.414 ppm
2018-03-14NOX 2004899140.947 ppm
2018-03-15NOX 2004900612.97 ppm
2018-11-29NOX 2005140970.872 ppm
2018-11-29NOX 2005141120.732 ppm
2019-03-18NOX 2005248951.17 ppm
2019-03-19NOX 2005250572.58 ppm
2019-03-19NOX 2005250603.72 ppm
2019-03-19NOX 2005250581.44 ppm
2019-03-19NOX 2005250593.10 ppm
2019-03-19NOX 2005250770.0200 ppm
2019-03-19NOX 2005250780.0510 ppm
2019-03-19NOX 2005250610.316 ppm
2019-03-19NOX 2005250970.491 ppm
2019-03-19NOX 2005250980.791 ppm
2019-05-08NOX 2005312970.986 ppm