Nitrate and nitrite
Washington
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.
52
Samples
0
Samples exceeding legal limit (MCL)
6
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 | 0.0434 ppm | 9 | 8 | ND - 0.150 ppm |
| 2015 | 0.0521 ppm | 9 | 7 | ND - 0.170 ppm |
| 2016 | 0.0733 ppm | 7 | 7 | 0.0170 ppm - 0.160 ppm |
| 2017 | 0.0738 ppm | 9 | 8 | ND - 0.190 ppm |
| 2018 | 0.0787 ppm | 9 | 9 | 0.0200 ppm - 0.180 ppm |
| 2019 | 0.0677 ppm | 9 | 8 | ND - 0.210 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 |
|---|---|---|
| 2014-01-28 | AC17144 | 0.0430 ppm |
| 2014-01-28 | AC17145 | 0.0120 ppm |
| 2014-01-28 | AC17146 | 0.0280 ppm |
| 2014-01-28 | AC17147 | 0.150 ppm |
| 2014-01-28 | AC17148 | 0.0390 ppm |
| 2014-01-28 | AC17149 | 0.0180 ppm |
| 2014-01-28 | AC17150 | ND |
| 2014-01-28 | AC17151 | 0.0360 ppm |
| 2014-01-28 | AC17143 | 0.0650 ppm |
| 2015-09-03 | AC57924 | 0.0290 ppm |
| 2015-09-03 | AC57928 | 0.0600 ppm |
| 2015-09-03 | AC57923 | ND |
| 2015-09-03 | AC57925 | 0.120 ppm |
| 2015-09-03 | AC57922 | 0.0260 ppm |
| 2015-09-03 | AC57921 | 0.170 ppm |
| 2015-09-03 | AC57926 | 0.0210 ppm |
| 2015-09-03 | AC57927 | ND |
| 2015-09-03 | AC57929 | 0.0430 ppm |
| 2016-08-16 | AC82136 | 0.0550 ppm |
| 2016-08-16 | AC82142 | 0.0450 ppm |
| 2016-08-16 | AC82139 | 0.140 ppm |
| 2016-08-16 | AC82138 | 0.160 ppm |
| 2016-08-16 | AC82134 | 0.0170 ppm |
| 2016-08-16 | AC82135 | 0.0670 ppm |
| 2016-08-16 | AC82140 | 0.0290 ppm |
| 2017-08-22 | AD03774 | 0.190 ppm |
| 2017-08-22 | AD03773 | 0.140 ppm |
| 2017-08-22 | AD03770 | 0.130 ppm |
| 2017-08-22 | AD03769 | 0.0290 ppm |
| 2017-08-22 | AD03768 | 0.0350 ppm |
| 2017-08-22 | AD03766 | 0.0200 ppm |
| 2017-08-22 | AD03771 | ND |
| 2017-08-22 | AD03772 | 0.0750 ppm |
| 2017-08-22 | AD03767 | 0.0450 ppm |
| 2018-08-21 | AD30898 | 0.0720 ppm |
| 2018-08-21 | AD30899 | 0.0500 ppm |
| 2018-08-21 | AD30897 | 0.0420 ppm |
| 2018-08-21 | AD30896 | 0.0720 ppm |
| 2018-08-21 | AD30895 | 0.0200 ppm |
| 2018-08-21 | AD30894 | 0.130 ppm |
| 2018-08-21 | AD30893 | 0.180 ppm |
| 2018-08-21 | AD30892 | 0.110 ppm |
| 2018-08-21 | AD30891 | 0.0320 ppm |
| 2019-08-27 | AD53705 | 0.0290 ppm |
| 2019-08-27 | AD53706 | 0.120 ppm |
| 2019-08-27 | AD53707 | 0.0760 ppm |
| 2019-08-27 | AD53708 | ND |
| 2019-08-27 | AD53709 | 0.210 ppm |
| 2019-08-27 | AD53710 | 0.0880 ppm |
| 2019-08-27 | AD53711 | 0.0120 ppm |
| 2019-08-27 | AD53712 | 0.0300 ppm |
| 2019-08-27 | AD53713 | 0.0440 ppm |