EWG's Tap Water Database — 2019 UPDATE



Water District 1 of Johnson County

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
20121.15 ppm660.760 ppm - 1.80 ppm
20130.864 ppm10100.200 ppm - 1.90 ppm
20140.386 ppm94ND - 1.40 ppm
20150.973 ppm65ND - 1.60 ppm
20162.17 ppm661.20 ppm - 3.30 ppm
20171.32 ppm660.290 ppm - 2.30 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
2012-03-06576121WS1.80 ppm
2012-03-06576120WS1.20 ppm
2012-05-22579207BT0.990 ppm
2012-05-22579206BT1.40 ppm
2012-05-29579491WS0.770 ppm
2012-05-29579493BT0.760 ppm
2013-03-05592968WS0.710 ppm
2013-03-05592969WS0.570 ppm
2013-05-01MAY2013-IOC-TP10.200 ppm
2013-05-01MAY2013-IOC-TP31.30 ppm
2013-05-01MAY2013-IOC-TP20.200 ppm
2013-05-14596073WS0.890 ppm
2013-06-04596868BT1.50 ppm
2013-06-04596869BT1.90 ppm
2013-07-08598142BT0.670 ppm
2013-07-08JUL2013-IOC-TP10.700 ppm
2014-03-04702601.40 ppm
2014-03-04702470.870 ppm
2014-05-131134430.200 ppm
2014-05-20MAY2014-IOC(2)-T1.000 ppm
2015-05-043225850.240 ppm
2015-05-043225861.30 ppm
2015-05-203355871.60 ppm
2015-05-203355851.60 ppm
2015-05-203355861.10 ppm
2016-05-175480243.30 ppm
2016-05-175480223.30 ppm
2016-05-175480231.20 ppm
2016-05-175480251.20 ppm
2016-06-205667341.90 ppm
2016-06-205667382.10 ppm
2017-02-147085521.000 ppm
2017-02-147085511.000 ppm
2017-02-147085501.60 ppm
2017-05-167620061.70 ppm
2017-05-167620022.30 ppm
2017-07-187993750.290 ppm