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EWG's Tap Water Database — 2021 UPDATE

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Nitrate and nitrite

Maryville

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
20140.180 ppm110.180 ppm
20150.0510 ppm110.0510 ppm
20160.310 ppm110.310 ppm
20170.0440 ppm110.0440 ppm
20180.110 ppm110.110 ppm
20190.360 ppm110.360 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
2014-11-17AC385270.180 ppm
2015-03-09AC437170.0510 ppm
2016-03-07AC677940.310 ppm
2017-03-13AC923050.0440 ppm
2018-03-12AD166370.110 ppm
2019-03-13AD406620.360 ppm