Nitrate and nitrite

City of Yakima Water Division

Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.

MORE ABOUT THIS CONTAMINANT

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	0.280 ppm	4	4	0.0600 ppm - 0.570 ppm
2015	0.294 ppm	5	4	ND - 0.540 ppm
2016	0.226 ppm	5	3	ND - 0.600 ppm
2017	0.328 ppm	5	5	0.0600 ppm - 0.590 ppm
2018	0.230 ppm	6	4	ND - 0.590 ppm
2019	0.184 ppm	5	4	ND - 0.490 ppm

ppm = parts per million

State and national drinking water standards and health guidelines

EWG Health Guideline 0.14 ppm

The health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.

EPA Maximum Contaminant
Level (MCL) 10 ppm

ppm = parts per million

All test results

Date	Lab ID	Result
2014-05-19	10055	0.250 ppm
2014-05-19	10054	0.570 ppm
2014-05-20	10226	0.240 ppm
2014-07-02	15582	0.0600 ppm
2015-03-25	06825	ND
2015-06-02	14785	0.540 ppm
2015-06-18	17275	0.270 ppm
2015-06-23	17602	0.220 ppm
2015-12-01	36088	0.440 ppm
2016-03-07		0.280 ppm
2016-04-20		ND
2016-05-09		0.250 ppm
2016-05-11		0.600 ppm
2016-05-18		ND
2017-02-27		0.0600 ppm
2017-03-28		0.280 ppm
2017-05-09		0.590 ppm
2017-05-09		0.230 ppm
2017-07-11		0.480 ppm
2018-03-12		ND
2018-03-26		0.260 ppm
2018-03-26		ND
2018-05-14		0.590 ppm
2018-05-14		0.250 ppm
2018-07-18		0.280 ppm
2019-03-18		ND
2019-05-08		0.0600 ppm
2019-05-29		0.280 ppm
2019-06-01		0.0900 ppm
2019-07-15		0.490 ppm