EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

Wilk-amite W/a #1-south

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
20120.330 ppm110.330 ppm
20130.345 ppm220.340 ppm - 0.350 ppm
20140.360 ppm220.360 ppm
20150.425 ppm220.390 ppm - 0.460 ppm
20160.440 ppm220.410 ppm - 0.470 ppm
20170.405 ppm220.380 ppm - 0.430 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
2012-01-18120119-025NI0.330 ppm
2013-01-30130131-018NI0.340 ppm
2013-11-12131114-017NI0.350 ppm
2014-01-21140122-087NI0.360 ppm
2014-01-21140122-085NI0.360 ppm
2015-11-30151201-004NI0.460 ppm
2015-11-30151201-002NI0.390 ppm
2016-03-16160317-038NI0.410 ppm
2016-03-16160317-005NI0.470 ppm
2017-03-22170323-037NI0.430 ppm
2017-03-22170323-032NI0.380 ppm