EWG's Tap Water Database — 2021 UPDATE


Nitrate and nitrite

Smiths Crossing Water Association

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
20140.684 ppm550.610 ppm - 0.900 ppm
20150.602 ppm550.490 ppm - 0.680 ppm
20160.500 ppm53ND - 0.950 ppm
20170.938 ppm550.740 ppm - 1.08 ppm
20181.17 ppm550.990 ppm - 1.30 ppm
20190.638 ppm54ND - 0.800 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
2014-05-14140515-019NI0.670 ppm
2014-05-14140515-018NI0.620 ppm
2014-05-14140515-017NI0.610 ppm
2014-05-14140515-016NI0.620 ppm
2014-05-14140515-008NI0.900 ppm
2015-05-13150514-039NI0.680 ppm
2015-05-13150514-038NI0.670 ppm
2015-05-13150514-037NI0.490 ppm
2015-05-13150514-036NI0.680 ppm
2015-05-13150514-035NI0.490 ppm
2016-05-24160525-024NI0.780 ppm
2016-05-24160525-023NI0.770 ppm
2016-05-24160525-015NI0.950 ppm
2017-03-28170329-053NI1.08 ppm
2017-03-28170329-052NI1.06 ppm
2017-03-28170329-051NI0.760 ppm
2017-03-28170329-049NI1.05 ppm
2017-03-28170329-046NI0.740 ppm
2018-04-03180404-017NI1.29 ppm
2018-04-03180404-016NI1.30 ppm
2018-04-03180404-015NI0.990 ppm
2018-04-03180404-014NI0.990 ppm
2018-04-03180404-013NI1.27 ppm
2019-04-09190410-011NI0.800 ppm
2019-04-09190410-014NI0.790 ppm
2019-04-09190410-013NI0.800 ppm
2019-04-09190410-012NI0.800 ppm