Nitrate and nitrite
Washington Suburban Sanitary Commission
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.
148
Samples
0
Samples exceeding legal limit (MCL)
146
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 | 1.47 ppm | 24 | 24 | 0.631 ppm - 2.30 ppm |
| 2015 | 1.17 ppm | 26 | 26 | 0.200 ppm - 2.15 ppm |
| 2016 | 1.10 ppm | 24 | 24 | 0.286 ppm - 2.26 ppm |
| 2017 | 1.06 ppm | 24 | 24 | 0.000845 ppm - 1.59 ppm |
| 2018 | 1.50 ppm | 26 | 25 | ND - 2.47 ppm |
| 2019 | 1.50 ppm | 24 | 24 | 0.682 ppm - 2.36 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 |
|---|---|---|
| 2014-01-14 | 140114_01_AC1481 | 1.74 ppm |
| 2014-01-14 | 140114_02_AC1475 | 0.793 ppm |
| 2014-02-11 | 140211_01_AC1772 | 2.17 ppm |
| 2014-02-11 | 140211_02_AC1765 | 1.44 ppm |
| 2014-03-11 | 140311_01_AC2047 | 2.30 ppm |
| 2014-03-11 | 140311_02_AC2039 | 1.70 ppm |
| 2014-04-08 | 140408_01_AC2379 | 1.89 ppm |
| 2014-04-08 | 140408_02_AC2372 | 1.90 ppm |
| 2014-05-13 | 140513_01_AC2793 | 1.78 ppm |
| 2014-05-13 | 140513_02_AC2785 | 1.58 ppm |
| 2014-06-10 | 140610_01_AC3095 | 1.95 ppm |
| 2014-06-10 | 140610_02_AC3087 | 1.39 ppm |
| 2014-07-08 | 140708_01_AC3395 | 1.92 ppm |
| 2014-07-08 | 140708_02_AC3383 | 1.35 ppm |
| 2014-08-12 | 140812_01_AC3774 | 1.42 ppm |
| 2014-09-09 | 140909_01_AC4066 | 1.20 ppm |
| 2014-09-09 | 140909_02_AC4059 | 0.631 ppm |
| 2014-10-14 | 141014_01_AC4498 | 1.42 ppm |
| 2014-10-14 | 141014_02_AC4498 | 0.759 ppm |
| 2014-10-14 | 141014_02_AC4489 | 0.759 ppm |
| 2014-11-11 | 141111_01_AC4846 | 1.53 ppm |
| 2014-11-11 | 141111_02_AC4835 | 0.755 ppm |
| 2014-12-09 | 141209_01_AC5092 | 1.92 ppm |
| 2014-12-09 | 141209_02_AC5084 | 0.864 ppm |
| 2015-01-13 | 150113_01_AC5416 | 1.63 ppm |
| 2015-01-13 | 150113_02_AC5408 | 0.978 ppm |
| 2015-02-10 | 150210_01_AC5726 | 2.15 ppm |
| 2015-02-10 | 150210_02_AC5718 | 1.22 ppm |
| 2015-03-10 | AC60011 | 1.23 ppm |
| 2015-03-10 | AC59937 | 1.49 ppm |
| 2015-04-14 | AC63895 | 1.08 ppm |
| 2015-04-14 | AC63822 | 1.66 ppm |
| 2015-05-12 | AC66987 | 1.20 ppm |
| 2015-05-12 | AC66902 | 1.35 ppm |
| 2015-06-09 | AC70075 | 1.66 ppm |
| 2015-06-09 | AC70000 | 1.26 ppm |
| 2015-07-14 | AC74036 | 1.39 ppm |
| 2015-07-14 | AC73910 | 1.14 ppm |
| 2015-07-21 | E16000223001 | 0.200 ppm |
| 2015-08-11 | AC77774 | 1.06 ppm |
| 2015-08-11 | AC77674 | 0.826 ppm |
| 2015-09-08 | AC81452 | 0.490 ppm |
| 2015-09-08 | AC81373 | 0.400 ppm |
| 2015-09-17 | E16001139001 | 0.970 ppm |
| 2015-10-13 | AC85685 | 1.67 ppm |
| 2015-10-13 | AC85607 | 0.697 ppm |
| 2015-11-10 | AC89420 | 1.53 ppm |
| 2015-11-10 | AC89364 | 0.730 ppm |
| 2015-12-08 | AC92451 | 1.57 ppm |
| 2015-12-08 | AC92374 | 0.806 ppm |
| 2016-01-12 | AC95928 | 1.32 ppm |
| 2016-01-12 | AC95850 | 0.889 ppm |
| 2016-02-09 | AC98982 | 2.01 ppm |
| 2016-02-09 | AC98902 | 1.03 ppm |
| 2016-03-08 | AD02021 | 2.26 ppm |
| 2016-03-08 | AD01942 | 1.48 ppm |
| 2016-04-12 | AD06053 | 1.55 ppm |
| 2016-04-12 | AD05968 | 1.60 ppm |
| 2016-05-10 | AD09826 | 1.07 ppm |
| 2016-05-10 | AD09746 | 1.45 ppm |
| 2016-06-14 | AD14066 | 1.30 ppm |
| 2016-06-14 | AD13984 | 1.21 ppm |
| 2016-07-12 | AD17149 | 1.05 ppm |
| 2016-07-12 | AD17048 | 1.09 ppm |
| 2016-08-09 | AD20301 | 0.666 ppm |
| 2016-08-11 | AD20903 | 0.964 ppm |
| 2016-09-13 | AD24906 | 0.286 ppm |
| 2016-09-13 | AD24834 | 0.304 ppm |
| 2016-10-11 | AD28158 | 1.15 ppm |
| 2016-10-11 | AD28098 | 0.625 ppm |
| 2016-11-08 | AD31549 | 0.704 ppm |
| 2016-11-08 | AD31575 | 0.585 ppm |
| 2016-12-13 | AD35544 | 1.10 ppm |
| 2016-12-13 | AD35474 | 0.634 ppm |
| 2017-01-10 | AD38445 | 1.59 ppm |
| 2017-01-10 | AD38372 | 0.000845 ppm |
| 2017-02-14 | AD42246 | 1.43 ppm |
| 2017-02-14 | AD42177 | 1.28 ppm |
| 2017-03-14 | AD45692 | 1.06 ppm |
| 2017-03-14 | AD45575 | 1.39 ppm |
| 2017-04-11 | AD49449 | 1.55 ppm |
| 2017-04-11 | AD49379 | 1.36 ppm |
| 2017-05-09 | AD52738 | 0.821 ppm |
| 2017-05-09 | AD52666 | 1.25 ppm |
| 2017-06-13 | AD56604 | 1.10 ppm |
| 2017-06-13 | AD56506 | 1.23 ppm |
| 2017-07-11 | AD59601 | 1.58 ppm |
| 2017-07-11 | AD59578 | 0.988 ppm |
| 2017-08-08 | AD62956 | 1.27 ppm |
| 2017-08-08 | AD62880 | 0.576 ppm |
| 2017-09-12 | AD67537 | 1.10 ppm |
| 2017-09-12 | AD67444 | 0.547 ppm |
| 2017-10-10 | AD70728 | 0.721 ppm |
| 2017-10-10 | AD70705 | 0.493 ppm |
| 2017-11-14 | AD74727 | 1.27 ppm |
| 2017-11-14 | AD74704 | 0.714 ppm |
| 2017-12-05 | AD76797 | 1.45 ppm |
| 2017-12-05 | AD76774 | 0.765 ppm |
| 2018-01-09 | AD80336 | 1.84 ppm |
| 2018-01-09 | AD80266 | 0.901 ppm |
| 2018-02-13 | AD84855 | 2.47 ppm |
| 2018-02-13 | AD84831 | 1.61 ppm |
| 2018-03-06 | E18003204001 | 0.390 ppm |
| 2018-03-08 | E18003249002 | 1.97 ppm |
| 2018-03-13 | AD88037 | 1.76 ppm |
| 2018-03-13 | AD88013 | 1.79 ppm |
| 2018-04-10 | AD91396 | 1.32 ppm |
| 2018-04-10 | AD91375 | 1.64 ppm |
| 2018-05-08 | AD94963 | 1.17 ppm |
| 2018-05-08 | AD94936 | 1.76 ppm |
| 2018-06-12 | AD98952 | 1.81 ppm |
| 2018-06-12 | AD98881 | 1.38 ppm |
| 2018-07-10 | AE02215 | ND |
| 2018-07-10 | AE02194 | 1.45 ppm |
| 2018-08-14 | AE06322 | 1.71 ppm |
| 2018-08-14 | AE06296 | 1.22 ppm |
| 2018-09-11 | AE09624 | 1.20 ppm |
| 2018-09-11 | AE09599 | 1.22 ppm |
| 2018-10-09 | AE12974 | 1.99 ppm |
| 2018-10-09 | AE13025 | 1.25 ppm |
| 2018-11-13 | AE17129 | 1.63 ppm |
| 2018-11-13 | AE17099 | 1.39 ppm |
| 2018-12-11 | AE20322 | 2.46 ppm |
| 2018-12-11 | AE20302 | 1.59 ppm |
| 2019-01-08 | AE23275 | 2.07 ppm |
| 2019-01-08 | AE23238 | 1.84 ppm |
| 2019-02-12 | AE27246 | 1.97 ppm |
| 2019-02-12 | AE27165 | 2.36 ppm |
| 2019-03-12 | AE30209 | 1.68 ppm |
| 2019-03-12 | AE30171 | 2.33 ppm |
| 2019-04-09 | AE33370 | 1.94 ppm |
| 2019-04-09 | AE33347 | 1.85 ppm |
| 2019-05-14 | AE37919 | 1.11 ppm |
| 2019-05-14 | AE37885 | 1.95 ppm |
| 2019-06-11 | AE41550 | 1.95 ppm |
| 2019-06-11 | AE41506 | 1.78 ppm |
| 2019-07-09 | AE44761 | 0.682 ppm |
| 2019-07-09 | AE44781 | 1.58 ppm |
| 2019-08-13 | AE49049 | 1.31 ppm |
| 2019-08-13 | AE48984 | 0.945 ppm |
| 2019-09-10 | AE52166 | 1.18 ppm |
| 2019-09-10 | AE52128 | 0.943 ppm |
| 2019-10-01 | AE54479-METALS | 0.977 ppm |
| 2019-10-01 | AE54476-METALS | 0.758 ppm |
| 2019-11-05 | AE58313-METALS | 1.55 ppm |
| 2019-11-19 | AE59864-METALS | 0.992 ppm |
| 2019-12-03 | AE61206-METALS | 1.37 ppm |
| 2019-12-03 | AE61294-METALS | 0.825 ppm |