EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

Averydale Mutual Water Company

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
20140.827 ppm330.550 ppm - 1.30 ppm
20151.40 ppm111.40 ppm
20170.943 ppm440.460 ppm - 1.50 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
2014-07-153761-001-13570.550 ppm
2014-07-153761-003-13341.30 ppm
2014-07-153761-006-14150.630 ppm
2015-02-173761-004-14141.40 ppm
2017-07-183761-001-12470.460 ppm
2017-07-183761-003-12151.50 ppm
2017-07-183761-004-12251.10 ppm
2017-07-183761-006-12530.710 ppm