Nitrate and nitrite
Valley Water Company
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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 6.19 ppm | 33 | 33 | 3.00 ppm - 12.0 ppm |
2015 | 6.84 ppm | 40 | 40 | 2.90 ppm - 13.0 ppm |
2016 | 4.55 ppm | 28 | 28 | 0.840 ppm - 11.0 ppm |
2017 | 7.60 ppm | 31 | 31 | 4.20 ppm - 12.0 ppm |
2018 | 5.52 ppm | 46 | 46 | 0.570 ppm - 11.0 ppm |
2019 | 6.68 ppm | 32 | 32 | 4.10 ppm - 11.0 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 |
---|---|---|
2014-05-05 | 9590-006-1030 | 5.10 ppm |
2014-05-12 | 9590-006-1020 | 4.80 ppm |
2014-05-19 | 9590-006-0745 | 3.40 ppm |
2014-05-27 | 9590-006-0830 | 4.80 ppm |
2014-06-02 | 9590-006-0730 | 3.20 ppm |
2014-06-09 | 9590-006-0800 | 3.90 ppm |
2014-06-16 | 9590-006-0800 | 4.20 ppm |
2014-06-23 | 9590-006-0730 | 3.00 ppm |
2014-07-02 | 9590-006-0850 | 5.50 ppm |
2014-07-02 | 9590-008-0910 | 12.0 ppm |
2014-07-07 | 9590-006-0830 | 5.20 ppm |
2014-07-14 | 9590-006-0745 | 5.30 ppm |
2014-07-21 | 9590-006-0830 | 5.40 ppm |
2014-07-28 | 9590-006-0830 | 5.20 ppm |
2014-08-04 | 9590-006-0900 | 6.20 ppm |
2014-08-04 | 9590-008-0845 | 12.0 ppm |
2014-08-11 | 9590-006-0730 | 5.00 ppm |
2014-08-18 | 9590-006-0815 | 5.20 ppm |
2014-08-25 | 9590-006-0900 | 5.10 ppm |
2014-09-02 | 9590-006-0900 | 4.40 ppm |
2014-09-02 | 9590-008-0900 | 11.0 ppm |
2014-09-03 | 9590-002-0810 | 12.0 ppm |
2014-09-03 | 9590-003-0830 | 11.0 ppm |
2014-09-09 | 9590-006-0800 | 4.40 ppm |
2014-09-15 | 9590-006-0745 | 4.90 ppm |
2014-09-22 | 9590-006-0830 | 4.80 ppm |
2014-09-29 | 9590-006-0745 | 4.60 ppm |
2014-10-06 | 9590-006-0730 | 4.70 ppm |
2014-10-06 | 9590-008-0730 | 12.0 ppm |
2014-10-07 | 9590-003-0915 | 12.0 ppm |
2014-10-13 | 9590-006-0730 | 4.60 ppm |
2014-10-20 | 9590-006-0800 | 4.70 ppm |
2014-10-27 | 9590-006-0900 | 4.80 ppm |
2015-04-06 | 9590-006-1125 | 4.40 ppm |
2015-04-10 | 9590-002-1030 | 13.0 ppm |
2015-04-13 | 9590-006-0900 | 5.20 ppm |
2015-04-20 | 9590-006-0800 | 4.40 ppm |
2015-04-27 | 9590-006-0825 | 4.20 ppm |
2015-05-04 | 9590-006-0800 | 4.20 ppm |
2015-05-08 | 9590-006-1445 | 5.20 ppm |
2015-05-11 | 9590-006-0815 | 4.20 ppm |
2015-05-18 | 9590-006-0920 | 7.60 ppm |
2015-05-26 | 9590-006-0840 | 3.80 ppm |
2015-06-04 | 9590-006-1345 | 4.40 ppm |
2015-06-08 | 9590-006-1120 | 3.60 ppm |
2015-06-15 | 9590-006-0815 | 3.10 ppm |
2015-06-22 | 9590-006-0800 | 3.10 ppm |
2015-06-29 | 9590-006-0815 | 2.90 ppm |
2015-07-06 | 9590-006-1130 | 5.90 ppm |
2015-07-13 | 9590-006-0730 | 3.80 ppm |
2015-07-20 | 9590-006-0740 | 6.30 ppm |
2015-07-27 | 9590-006-0845 | 4.10 ppm |
2015-08-10 | 9590-006-1045 | 6.30 ppm |
2015-08-17 | 9590-006-0800 | 6.30 ppm |
2015-08-24 | 9590-006-0740 | 5.80 ppm |
2015-08-31 | 9590-006-0815 | 5.60 ppm |
2015-09-08 | 9590-006-0800 | 3.90 ppm |
2015-09-10 | 9590-006-1330 | 8.00 ppm |
2015-09-10 | 9590-008-1340 | 13.0 ppm |
2015-09-14 | 9590-006-0810 | 7.00 ppm |
2015-09-21 | 9590-006-1125 | 7.30 ppm |
2015-09-28 | 9590-006-0810 | 7.10 ppm |
2015-10-05 | 9590-002-0945 | 12.0 ppm |
2015-10-05 | 9590-003-0850 | 13.0 ppm |
2015-10-05 | 9590-006-0825 | 7.50 ppm |
2015-10-05 | 9590-008-0815 | 13.0 ppm |
2015-10-12 | 9590-006-1050 | 7.30 ppm |
2015-10-19 | 9590-006-0830 | 6.80 ppm |
2015-10-26 | 9590-006-0810 | 7.00 ppm |
2015-11-02 | 9590-002-0915 | 12.0 ppm |
2015-11-02 | 9590-003-0930 | 12.0 ppm |
2015-11-02 | 9590-006-0955 | 7.30 ppm |
2015-11-02 | 9590-008-0945 | 12.0 ppm |
2016-03-01 | 9590-003-0810 | 0.840 ppm |
2016-03-01 | 9590-006-0800 | 0.840 ppm |
2016-04-04 | 9590-005-1215 | 6.50 ppm |
2016-04-04 | 9590-006-1230 | 1.60 ppm |
2016-04-11 | 9590-006-0800 | 3.20 ppm |
2016-04-18 | 9590-006-0750 | 1.80 ppm |
2016-04-25 | 9590-006-0825 | 1.80 ppm |
2016-05-02 | 9590-006-0800 | 1.80 ppm |
2016-05-04 | 9590-005-0815 | 8.60 ppm |
2016-05-09 | 9590-006-0930 | 1.80 ppm |
2016-05-16 | 9590-006-0845 | 2.00 ppm |
2016-05-17 | 9590-006-1105 | 4.20 ppm |
2016-05-23 | 9590-006-0800 | 2.80 ppm |
2016-06-01 | 9590-006-0820 | 3.10 ppm |
2016-07-05 | 9590-006-0830 | 4.40 ppm |
2016-07-05 | 9590-008-0835 | 10.00 ppm |
2016-07-11 | 9590-006-0815 | 4.50 ppm |
2016-07-18 | 9590-006-0850 | 6.10 ppm |
2016-07-25 | 9590-006-0815 | 5.90 ppm |
2016-08-01 | 9590-006-0910 | 6.10 ppm |
2016-08-08 | 9590-006-0815 | 5.70 ppm |
2016-08-15 | 9590-006-0800 | 4.40 ppm |
2016-08-29 | 9590-006-0820 | 4.90 ppm |
2016-10-03 | 9590-006-0815 | 5.70 ppm |
2016-10-03 | 9590-008-0820 | 11.0 ppm |
2016-10-10 | 9590-006-0830 | 5.90 ppm |
2016-10-18 | 9590-006-0815 | 6.00 ppm |
2016-10-25 | 9590-006-0835 | 6.00 ppm |
2017-05-15 | 9590-006-0940 | 4.20 ppm |
2017-05-15 | 9590-008-0950 | 11.0 ppm |
2017-05-19 | 9590-006-1230 | 5.40 ppm |
2017-05-19 | 9590-008-1300 | 11.0 ppm |
2017-05-22 | 9590-006-0830 | 7.50 ppm |
2017-05-30 | 9590-006-0815 | 7.50 ppm |
2017-07-05 | 9590-006-0900 | 5.30 ppm |
2017-07-05 | 9590-008-0900 | 12.0 ppm |
2017-07-10 | 9590-006-0855 | 7.20 ppm |
2017-07-18 | 9590-006-0845 | 6.80 ppm |
2017-07-24 | 9590-006-0800 | 6.60 ppm |
2017-08-01 | 9590-006-0900 | 7.00 ppm |
2017-08-01 | 9590-008-0850 | 12.0 ppm |
2017-08-07 | 9590-006-0815 | 6.50 ppm |
2017-08-14 | 9590-006-0820 | 6.10 ppm |
2017-08-21 | 9590-006-0855 | 6.60 ppm |
2017-08-28 | 9590-006-0815 | 6.60 ppm |
2017-09-05 | 9590-006-0815 | 6.10 ppm |
2017-09-05 | 9590-008-0820 | 11.0 ppm |
2017-09-11 | 9590-006-1000 | 6.60 ppm |
2017-09-18 | 9590-006-0800 | 6.40 ppm |
2017-09-25 | 9590-006-0800 | 6.50 ppm |
2017-10-02 | 9590-006-0815 | 6.40 ppm |
2017-10-02 | 9590-008-0815 | 11.0 ppm |
2017-10-03 | 9590-002-0745 | 12.0 ppm |
2017-10-09 | 9590-006-0840 | 4.40 ppm |
2017-10-16 | 9590-006-0810 | 6.60 ppm |
2017-10-23 | 9590-006-0845 | 4.50 ppm |
2017-10-30 | 9590-006-1010 | 6.20 ppm |
2017-11-02 | 9590-002-0845 | 12.0 ppm |
2017-11-02 | 9590-006-0920 | 6.70 ppm |
2018-03-12 | 9590-002-1005 | 4.40 ppm |
2018-03-12 | 9590-003-1050 | 0.570 ppm |
2018-03-12 | 9590-004-0900 | 9.20 ppm |
2018-03-12 | 9590-005-0930 | 2.70 ppm |
2018-03-12 | 9590-006-1355 | 0.570 ppm |
2018-03-19 | 9590-006-0900 | 1.10 ppm |
2018-03-26 | 9590-006-1120 | 1.60 ppm |
2018-05-03 | 9590-006-0745 | 4.20 ppm |
2018-05-03 | 9590-008-0735 | 6.90 ppm |
2018-05-07 | 9590-006-0750 | 4.20 ppm |
2018-05-14 | 9590-006-0900 | 4.60 ppm |
2018-05-22 | 9590-006-0905 | 5.00 ppm |
2018-05-29 | 9590-006-1450 | 5.00 ppm |
2018-06-04 | 9590-006-0800 | 5.20 ppm |
2018-06-04 | 9590-008-0800 | 8.70 ppm |
2018-06-11 | 9590-006-0800 | 5.40 ppm |
2018-06-18 | 9590-006-0850 | 5.90 ppm |
2018-06-25 | 9590-006-0800 | 5.60 ppm |
2018-07-02 | 9590-006-0800 | 3.90 ppm |
2018-07-02 | 9590-008-0800 | 9.70 ppm |
2018-07-09 | 9590-006-0835 | 3.80 ppm |
2018-07-16 | 9590-006-0825 | 4.00 ppm |
2018-07-23 | 9590-006-0800 | 3.80 ppm |
2018-07-30 | 9590-006-0830 | 5.10 ppm |
2018-08-06 | 9590-006-0815 | 3.70 ppm |
2018-08-06 | 9590-008-0830 | 10.00 ppm |
2018-08-13 | 9590-006-0800 | 3.70 ppm |
2018-08-20 | 9590-006-0745 | 4.20 ppm |
2018-08-27 | 9590-006-0730 | 3.50 ppm |
2018-09-04 | 9590-002-0930 | 11.0 ppm |
2018-09-04 | 9590-006-0800 | 3.70 ppm |
2018-09-04 | 9590-008-0800 | 11.0 ppm |
2018-09-10 | 9590-006-0730 | 4.00 ppm |
2018-09-17 | 9590-006-0800 | 3.70 ppm |
2018-09-24 | 9590-006-0800 | 4.00 ppm |
2018-10-01 | 9590-006-1100 | 5.70 ppm |
2018-10-01 | 9590-008-1050 | 11.0 ppm |
2018-10-03 | 9590-002-1010 | 11.0 ppm |
2018-10-03 | 9590-003-1020 | 10.00 ppm |
2018-10-08 | 9590-006-0815 | 5.20 ppm |
2018-10-17 | 9590-006-0800 | 5.60 ppm |
2018-10-22 | 9590-006-0800 | 5.40 ppm |
2018-10-29 | 9590-006-0830 | 5.40 ppm |
2018-11-05 | 9590-006-0800 | 5.10 ppm |
2018-11-05 | 9590-008-0800 | 11.0 ppm |
2018-11-12 | 9590-006-0800 | 5.10 ppm |
2019-05-06 | 9590-006-1250 | 4.90 ppm |
2019-05-06 | 9590-008-1315 | 7.60 ppm |
2019-05-13 | 9590-006-0755 | 7.70 ppm |
2019-05-20 | 9590-006-0800 | 8.20 ppm |
2019-05-28 | 9590-006-0815 | 8.70 ppm |
2019-06-03 | 9590-006-0840 | 6.50 ppm |
2019-06-03 | 9590-008-0830 | 8.70 ppm |
2019-06-10 | 9590-006-0800 | 6.40 ppm |
2019-06-17 | 9590-006-0815 | 6.80 ppm |
2019-06-24 | 9590-006-0835 | 7.90 ppm |
2019-07-01 | 9590-006-0800 | 5.80 ppm |
2019-07-01 | 9590-008-0800 | 10.00 ppm |
2019-07-08 | 9590-006-0745 | 6.10 ppm |
2019-07-15 | 9590-006-0845 | 5.80 ppm |
2019-07-22 | 9590-006-0800 | 5.60 ppm |
2019-07-29 | 9590-006-0820 | 5.70 ppm |
2019-08-05 | 9590-006-0900 | 4.40 ppm |
2019-08-05 | 9590-008-0855 | 11.0 ppm |
2019-08-12 | 9590-006-0850 | 4.10 ppm |
2019-08-19 | 9590-006-0855 | 4.20 ppm |
2019-08-26 | 9590-006-0820 | 5.60 ppm |
2019-09-03 | 9590-006-0800 | 5.70 ppm |
2019-09-03 | 9590-008-0800 | 11.0 ppm |
2019-09-09 | 9590-006-0912 | 6.00 ppm |
2019-09-16 | 9590-006-0810 | 4.40 ppm |
2019-09-23 | 9590-006-0840 | 5.50 ppm |
2019-10-01 | 9590-006-0810 | 6.00 ppm |
2019-10-02 | 9590-008-1015 | 11.0 ppm |
2019-10-07 | 9590-006-0850 | 5.80 ppm |
2019-10-14 | 9590-006-0815 | 5.50 ppm |
2019-10-21 | 9590-006-0815 | 5.40 ppm |
2019-10-28 | 9590-006-0840 | 5.60 ppm |