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EWG's Tap Water Database — 2021 UPDATE

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Nitrate

Washington Suburban Sanitary Commission

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.

MORE ABOUT THIS CONTAMINANT

 

144

Samples

0

Samples exceeding legal limit (MCL)

144

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20141.47 ppm24240.631 ppm - 2.30 ppm
20151.20 ppm24240.390 ppm - 2.15 ppm
20161.09 ppm24240.276 ppm - 2.25 ppm
20171.09 ppm24240.483 ppm - 1.58 ppm
20181.57 ppm24240.891 ppm - 2.46 ppm
20191.49 ppm24240.672 ppm - 2.35 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
2014-01-14140114_01_AC14811.74 ppm
2014-01-14140114_02_AC14750.793 ppm
2014-02-11140211_01_AC17722.17 ppm
2014-02-11140211_02_AC17651.44 ppm
2014-03-11140311_01_AC20472.30 ppm
2014-03-11140311_02_AC20391.70 ppm
2014-04-08140408_01_AC23791.89 ppm
2014-04-08140408_02_AC23721.90 ppm
2014-05-13140513_01_AC27931.78 ppm
2014-05-13140513_02_AC27851.58 ppm
2014-06-10140610_01_AC30951.95 ppm
2014-06-10140610_02_AC30871.39 ppm
2014-07-08140708_01_AC33951.92 ppm
2014-07-08140708_02_AC33831.35 ppm
2014-08-12140812_01_AC37741.42 ppm
2014-09-09140909_01_AC40661.20 ppm
2014-09-09140909_02_AC40590.631 ppm
2014-10-14141014_01_AC44981.42 ppm
2014-10-14141014_02_AC44980.759 ppm
2014-10-14141014_02_AC44890.759 ppm
2014-11-11141111_01_AC48461.53 ppm
2014-11-11141111_02_AC48350.755 ppm
2014-12-09141209_01_AC50921.92 ppm
2014-12-09141209_02_AC50840.864 ppm
2015-01-13150113_01_AC54161.63 ppm
2015-01-13150113_02_AC54080.978 ppm
2015-02-10150210_01_AC57262.15 ppm
2015-02-10150210_02_AC57181.22 ppm
2015-03-10AC600111.22 ppm
2015-03-10AC599371.48 ppm
2015-04-14AC638951.07 ppm
2015-04-14AC638221.61 ppm
2015-05-12AC669871.19 ppm
2015-05-12AC669021.30 ppm
2015-06-09AC700751.65 ppm
2015-06-09AC700001.25 ppm
2015-07-14AC740361.38 ppm
2015-07-14AC739101.13 ppm
2015-08-11AC777741.05 ppm
2015-08-11AC776740.776 ppm
2015-09-08AC814520.480 ppm
2015-09-08AC813730.390 ppm
2015-10-13AC856851.66 ppm
2015-10-13AC856070.687 ppm
2015-11-10AC894201.52 ppm
2015-11-10AC893640.680 ppm
2015-12-08AC924511.56 ppm
2015-12-08AC923740.756 ppm
2016-01-12AC959281.31 ppm
2016-01-12AC958500.879 ppm
2016-02-09AC989822.00 ppm
2016-02-09AC989021.02 ppm
2016-03-08AD020212.25 ppm
2016-03-08AD019421.47 ppm
2016-04-12AD060531.54 ppm
2016-04-12AD059681.59 ppm
2016-05-10AD098261.06 ppm
2016-05-10AD097461.44 ppm
2016-06-14AD140661.29 ppm
2016-06-14AD139841.20 ppm
2016-07-12AD171491.04 ppm
2016-07-12AD170481.08 ppm
2016-08-09AD203010.656 ppm
2016-08-11AD209030.954 ppm
2016-09-13AD249060.276 ppm
2016-09-13AD248340.294 ppm
2016-10-11AD281581.14 ppm
2016-10-11AD280980.615 ppm
2016-11-08AD315490.694 ppm
2016-11-08AD315750.575 ppm
2016-12-13AD355441.09 ppm
2016-12-13AD354740.624 ppm
2017-01-10AD384451.58 ppm
2017-01-10AD383720.835 ppm
2017-02-14AD422461.42 ppm
2017-02-14AD421771.27 ppm
2017-03-14AD456921.05 ppm
2017-03-14AD455751.38 ppm
2017-04-11AD494491.54 ppm
2017-04-11AD493791.35 ppm
2017-05-09AD527380.811 ppm
2017-05-09AD526661.24 ppm
2017-06-13AD566041.09 ppm
2017-06-13AD565061.22 ppm
2017-07-11AD596011.57 ppm
2017-07-11AD595780.978 ppm
2017-08-08AD629561.26 ppm
2017-08-08AD628800.566 ppm
2017-09-12AD675371.09 ppm
2017-09-12AD674440.537 ppm
2017-10-10AD707280.711 ppm
2017-10-10AD707050.483 ppm
2017-11-14AD747271.26 ppm
2017-11-14AD747040.704 ppm
2017-12-05AD767971.44 ppm
2017-12-05AD767740.755 ppm
2018-01-09AD803361.83 ppm
2018-01-09AD802660.891 ppm
2018-02-13AD848552.46 ppm
2018-02-13AD848311.60 ppm
2018-03-13AD880371.75 ppm
2018-03-13AD880131.78 ppm
2018-04-10AD913961.31 ppm
2018-04-10AD913751.63 ppm
2018-05-08AD949631.16 ppm
2018-05-08AD949361.75 ppm
2018-06-12AD989521.80 ppm
2018-06-12AD988811.37 ppm
2018-07-10AE022151.35 ppm
2018-07-10AE021941.44 ppm
2018-08-14AE063221.70 ppm
2018-08-14AE062961.21 ppm
2018-09-11AE096241.19 ppm
2018-09-11AE095991.21 ppm
2018-10-09AE129741.98 ppm
2018-10-09AE130251.24 ppm
2018-11-13AE171291.62 ppm
2018-11-13AE170991.38 ppm
2018-12-11AE203222.45 ppm
2018-12-11AE203021.58 ppm
2019-01-08AE232752.06 ppm
2019-01-08AE232381.83 ppm
2019-02-12AE272461.96 ppm
2019-02-12AE271652.35 ppm
2019-03-12AE302091.67 ppm
2019-03-12AE301712.32 ppm
2019-04-09AE333701.93 ppm
2019-04-09AE333471.84 ppm
2019-05-14AE379191.10 ppm
2019-05-14AE378851.94 ppm
2019-06-11AE415501.94 ppm
2019-06-11AE415061.77 ppm
2019-07-09AE447610.672 ppm
2019-07-09AE447811.57 ppm
2019-08-13AE490491.30 ppm
2019-08-13AE489840.935 ppm
2019-09-10AE521661.17 ppm
2019-09-10AE521280.933 ppm
2019-10-01AE54479-METALS0.967 ppm
2019-10-01AE54476-METALS0.748 ppm
2019-11-05AE58313-METALS1.54 ppm
2019-11-19AE59864-METALS0.982 ppm
2019-12-03AE61206-METALS1.37 ppm
2019-12-03AE61294-METALS0.825 ppm