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EWG's Tap Water Database — 2021 UPDATE

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Nitrate and nitrite

Oxbow Mining Waterworks

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.

 

6

Samples

0

Samples exceeding legal limit (MCL)

3

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.143 ppm110.143 ppm
20150.438 ppm110.438 ppm
2016ND10ND
20170.140 ppm110.140 ppm
20180.112 ppm110.112 ppm
20190.269 ppm110.269 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 Result
2014-04-010.143 ppm
2015-05-120.438 ppm
2016-04-26ND
2017-03-200.140 ppm
2018-02-130.112 ppm
2019-02-260.269 ppm