EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

Coke County Water Supply Corporation

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
20120.0200 ppm110.0200 ppm
20130.356 ppm110.356 ppm
20141.46 ppm111.46 ppm
20150.320 ppm110.320 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
2012-03-07AB831780.0200 ppm
2014-11-24Q14573230031.46 ppm
2015-03-30Q15115260010.320 ppm