EWG's Tap Water Database — 2019 UPDATE


Nitrate and nitrite

City of Duncanville

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
20120.437 ppm330.430 ppm - 0.450 ppm
20140.419 ppm330.346 ppm - 0.556 ppm
20150.593 ppm330.550 ppm - 0.630 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
2012-02-2112025900010.430 ppm
2012-02-2112025900020.430 ppm
2012-02-2112025900030.450 ppm
2014-10-27Q14539980010.346 ppm
2014-10-27Q14539980020.556 ppm
2014-10-27Q14539980030.356 ppm
2015-06-16Q15222120010.550 ppm
2015-06-16Q15222120020.630 ppm
2015-06-16Q15222120030.600 ppm