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EWG's Tap Water Database — 2019 UPDATE

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Nitrate

Issaquah Water System

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.

 

24

Samples

0

Samples exceeding legal limit (MCL)

18

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.308 ppm43ND - 0.510 ppm
20130.318 ppm43ND - 0.500 ppm
20140.320 ppm43ND - 0.510 ppm
20150.313 ppm43ND - 0.490 ppm
20160.315 ppm43ND - 0.540 ppm
20170.393 ppm43ND - 0.640 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
2012-05-07166290.430 ppm
2012-05-07166320.290 ppm
2012-05-0716633ND
2012-05-07166260.510 ppm
2013-05-20202260.500 ppm
2013-05-20202270.420 ppm
2013-05-20202280.350 ppm
2013-05-2020229ND
2014-05-19216030.510 ppm
2014-05-19216040.430 ppm
2014-05-19216050.340 ppm
2014-05-1921606ND
2015-05-29242100.430 ppm
2015-05-2924212ND
2015-05-29242110.330 ppm
2015-05-29242090.490 ppm
2016-07-250.490 ppm
2016-07-250.540 ppm
2016-07-25ND
2016-07-250.230 ppm
2017-08-150.310 ppm
2017-08-150.620 ppm
2017-08-150.640 ppm
2017-08-15ND