EWG's Tap Water Database — 2019 UPDATE



Osage City, City of

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
20120.265 ppm220.230 ppm - 0.300 ppm
20130.145 ppm21ND - 0.290 ppm
20150.340 ppm220.260 ppm - 0.420 ppm
20160.615 ppm220.590 ppm - 0.640 ppm
20170.535 ppm220.500 ppm - 0.570 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
2012-05-15578866WS0.300 ppm
2012-06-06579811BT0.230 ppm
2013-06-04596851BT0.290 ppm
2015-05-063285730.260 ppm
2015-05-183341050.420 ppm
2016-05-025362640.640 ppm
2016-05-165463910.590 ppm
2017-05-117596100.570 ppm
2017-05-167619800.500 ppm