Nitrate and nitrite

Bethesda WSC

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
2013	N/A	0	0	N/A
2014	0.327 ppm	5	5	0.0660 ppm - 1.13 ppm
2015	0.358 ppm	16	15	ND - 1.01 ppm
2016	N/A	0	0	N/A
2017	N/A	0	0	N/A
2018	0.162 ppm	1	1	0.162 ppm
2019	0.520 ppm	2	2	0.290 ppm - 0.749 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
2014-10-07	Q1451274003	1.13 ppm
2014-11-19	Q1456730004	0.142 ppm
2014-11-19	Q1456730003	0.0660 ppm
2014-11-19	Q1456730002	0.0935 ppm
2014-11-19	Q1456730001	0.202 ppm
2015-02-03	Q1504044004	0.104 ppm
2015-04-22	Q1515039014	0.826 ppm
2015-04-22	Q1515039020	0.128 ppm
2015-04-22	Q1515039019	0.0720 ppm
2015-04-22	Q1515039018	0.120 ppm
2015-04-22	Q1515039017	0.124 ppm
2015-04-22	Q1515039016	0.771 ppm
2015-04-22	Q1515039013	ND
2015-04-22	Q1515039012	0.824 ppm
2015-04-22	Q1515039011	0.0885 ppm
2015-04-22	Q1515039010	0.584 ppm
2015-04-22	Q1515039009	1.01 ppm
2015-06-17	Q1522819001	0.0355 ppm
2015-08-04	Q1530163003	0.0550 ppm
2015-08-04	Q1530163001	0.502 ppm
2015-08-04	Q1530163002	0.480 ppm
2018-02-21	Q1807322003	0.162 ppm
2019-01-15	Q1901990017	0.290 ppm
2019-09-26	Q1969539001	0.749 ppm