EWG's Tap Water Database — 2021 UPDATE


Nitrate and nitrite

Kwethluk New Piped Water System

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
20150.125 ppm330.103 ppm - 0.138 ppm
20160.266 ppm220.147 ppm - 0.385 ppm
20190.216 ppm110.216 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
2015-06-08IN*A1506157-01B0.134 ppm
2015-09-02IN*A1509043-01B0.138 ppm
2015-10-14IN*A1510210-01B0.103 ppm
2016-03-08IN*A1603154-01A0.385 ppm
2016-05-12IN*A1605312-01A0.147 ppm
2019-03-28ARS3-19-00927-000.216 ppm