EWG's Tap Water Database — 2019 UPDATE



City of Columbia

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
20120.244 ppm220.0580 ppm - 0.430 ppm
20130.250 ppm220.0500 ppm - 0.450 ppm
20140.230 ppm220.1000 ppm - 0.360 ppm
20150.237 ppm220.0840 ppm - 0.390 ppm
20160.345 ppm220.220 ppm - 0.470 ppm
20170.132 ppm32ND - 0.320 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
2012-02-06AD023070.0580 ppm
2012-02-06AD023080.430 ppm
2013-01-30AD190880.450 ppm
2013-01-30AD190890.0500 ppm
2014-01-15AD345350.1000 ppm
2014-01-15AD345360.360 ppm
2015-01-15AD503480.0840 ppm
2015-01-15AD503470.390 ppm
2016-01-13AD691920.470 ppm
2016-01-13AD691910.220 ppm
2017-01-17AD883560.0770 ppm
2017-03-07AD907170.320 ppm