EWG's Tap Water Database — 2019 UPDATE



City of Duncanville

Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. 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
20130.450 ppm330.360 ppm - 0.550 ppm
20140.419 ppm330.346 ppm - 0.556 ppm
20150.561 ppm330.530 ppm - 0.604 ppm
20160.511 ppm330.496 ppm - 0.534 ppm
20170.658 ppm330.439 ppm - 0.863 ppm

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.

EPA Maximum Contaminant
Level (MCL) 10 ppm

The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.

ppm = parts per million

All test results

Date Lab ID Result
2012-02-2112025900030.450 ppm
2012-02-2112025900020.430 ppm
2012-02-2112025900010.430 ppm
2013-02-1313024810030.440 ppm
2013-02-1313024810020.550 ppm
2013-02-1313024810010.360 ppm
2014-10-27Q14539980010.346 ppm
2014-10-27Q14539980030.356 ppm
2014-10-27Q14539980020.556 ppm
2015-06-16Q15222120030.548 ppm
2015-06-16Q15222120020.604 ppm
2015-06-16Q15222120010.530 ppm
2016-04-06Q16136340020.502 ppm
2016-04-06Q16136340010.534 ppm
2016-04-06Q16136340070.496 ppm
2017-01-11Q17015520040.863 ppm
2017-01-11Q17015520030.673 ppm
2017-12-08Q17648150010.439 ppm