EWG's Tap Water Database — 2019 UPDATE



South-Central Service Area

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
20120.290 ppm220.260 ppm - 0.320 ppm
20130.199 ppm220.0840 ppm - 0.313 ppm
20140.321 ppm220.320 ppm - 0.321 ppm
20150.368 ppm220.366 ppm - 0.369 ppm
20160.240 ppm220.227 ppm - 0.253 ppm
20170.211 ppm220.210 ppm - 0.212 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 Result
2012-09-040.260 ppm
2012-09-040.320 ppm
2013-08-060.313 ppm
2013-08-060.0840 ppm
2014-07-210.320 ppm
2014-07-210.321 ppm
2015-08-040.366 ppm
2015-08-040.369 ppm
2016-09-140.253 ppm
2016-09-140.227 ppm
2017-08-250.210 ppm
2017-08-250.212 ppm