EWG's Tap Water Database — 2021 UPDATE


Nitrate and nitrite

La Jara Water Users Association

Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. 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
20140.320 ppm110.320 ppm
20150.290 ppm110.290 ppm
20160.410 ppm110.410 ppm
20170.160 ppm110.160 ppm
20180.110 ppm110.110 ppm
20190.150 ppm110.150 ppm

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.

EPA Maximum Contaminant
Level (MCL) 10 ppm

ppm = parts per million

All test results

Date Lab ID Result
2014-05-1320140160360.320 ppm
2015-05-1920150151670.290 ppm
2016-05-1720160142680.410 ppm
2017-06-0620170169670.160 ppm
2018-09-1820180270030.110 ppm
2019-03-1220190063640.150 ppm