Nitrate
City of Post Falls
Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 0.986 ppm | 21 | 21 | 0.430 ppm - 1.39 ppm |
| 2019 | 0.968 ppm | 14 | 14 | 0.444 ppm - 1.45 ppm |
| 2020 | 0.874 ppm | 10 | 10 | 0.395 ppm - 1.17 ppm |
| 2021 | 0.687 ppm | 11 | 11 | 0.367 ppm - 0.939 ppm |
| 2022 | 0.741 ppm | 12 | 12 | 0.484 ppm - 0.952 ppm |
| 2023 | 0.747 ppm | 21 | 21 | 0.371 ppm - 1.76 ppm |
ppm = parts per million
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.14 ppm
The EWG 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
The legal limit for nitrate, established in 1962, was developed to protect infants from acute methemoglobinemia, a life-threatening disorder of oxygen transport in the body. This limit does not fully protect against the risk of cancer and harm to the developing fetus.
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-03-13 | I180313043004 | 1.20 ppm |
| 2018-03-13 | I180313043003 | 1.13 ppm |
| 2018-03-13 | I180313043001 | 1.06 ppm |
| 2018-03-13 | I180313043002 | 1.14 ppm |
| 2018-07-17 | I180717054001 | 0.734 ppm |
| 2018-07-17 | I180717054003 | 1.13 ppm |
| 2018-07-17 | I180717054004 | 1.12 ppm |
| 2018-07-17 | I170717054003 | 1.13 ppm |
| 2018-07-17 | I180717054002 | 0.753 ppm |
| 2018-07-17 | 8180717054001 | 0.734 ppm |
| 2018-11-06 | I181106039004 | 1.10 ppm |
| 2018-11-06 | I181106039002 | 0.638 ppm |
| 2018-11-06 | I181106039003 | 1.04 ppm |
| 2018-11-06 | I181106039001 | 1.04 ppm |
| 2018-12-18 | N200287 | 0.640 ppm |
| 2018-12-18 | N200286 | 1.27 ppm |
| 2018-12-18 | N200285 | 0.650 ppm |
| 2018-12-18 | N200284 | 1.39 ppm |
| 2018-12-18 | N200283 | 0.430 ppm |
| 2018-12-19 | N200327 | 1.15 ppm |
| 2018-12-19 | N200326 | 1.23 ppm |
| 2019-03-12 | I190312040001 | 0.922 ppm |
| 2019-03-12 | I190312040002 | 1.01 ppm |
| 2019-03-12 | I190312040003 | 1.20 ppm |
| 2019-07-16 | I190716024003 | 1.13 ppm |
| 2019-07-16 | I19071624001 | 0.444 ppm |
| 2019-07-16 | I190716024002 | 0.787 ppm |
| 2019-07-16 | I190716024004 | 1.12 ppm |
| 2019-11-12 | I210891 | 1.09 ppm |
| 2019-11-13 | I210941 | 1.10 ppm |
| 2019-11-18 | I211059 | 0.673 ppm |
| 2019-11-18 | I211062 | 0.648 ppm |
| 2019-11-19 | I211103 | 0.802 ppm |
| 2019-12-09 | I211716 | 1.18 ppm |
| 2019-12-16 | I211917 | 1.45 ppm |
| 2020-03-25 | IMAC026103 | 1.12 ppm |
| 2020-03-25 | IMAC026101 | 0.867 ppm |
| 2020-03-25 | IMAC026102 | 1.09 ppm |
| 2020-09-22 | N220857 | 0.923 ppm |
| 2020-09-22 | N220853 | 0.907 ppm |
| 2020-09-22 | N220855 | 1.17 ppm |
| 2020-09-22 | N220854 | 0.968 ppm |
| 2020-09-22 | N1280147 | 0.620 ppm |
| 2020-09-22 | N220851 | 0.395 ppm |
| 2020-09-22 | N220856 | 0.676 ppm |
| 2021-09-01 | IMBI005301 | 0.367 ppm |
| 2021-11-23 | N235746 | 0.939 ppm |
| 2021-11-23 | N235744 | 0.507 ppm |
| 2021-11-23 | N235745 | 0.786 ppm |
| 2021-11-23 | N235747 | 0.600 ppm |
| 2021-11-29 | N235856 | 0.468 ppm |
| 2021-11-29 | N235796 | 0.628 ppm |
| 2021-11-29 | N235797 | 0.749 ppm |
| 2021-12-10 | NMBL038101 | 0.899 ppm |
| 2021-12-10 | NMBL038103 | 0.757 ppm |
| 2021-12-10 | NMBL038102 | 0.854 ppm |
| 2022-03-09 | I238691 | 0.859 ppm |
| 2022-03-09 | N238690 | 0.952 ppm |
| 2022-03-14 | I238767 | 0.692 ppm |
| 2022-03-14 | N238766 | 0.897 ppm |
| 2022-03-23 | PHDMCC081103 | 0.686 ppm |
| 2022-03-23 | PHDMCC081102 | 0.935 ppm |
| 2022-06-06 | I241708 | 0.651 ppm |
| 2022-06-07 | I241735 | 0.484 ppm |
| 2022-07-13 | I243511 | 0.540 ppm |
| 2022-11-10 | PHDMCK035803 | 0.674 ppm |
| 2022-11-10 | PHDMCK035802 | 0.739 ppm |
| 2022-11-10 | PHDMCK035701 | 0.780 ppm |
| 2023-01-23 | N251500 | 0.902 ppm |
| 2023-01-23 | N251501 | 0.847 ppm |
| 2023-01-25 | N251563 | 0.457 ppm |
| 2023-03-24 | IMDC083503 | 0.880 ppm |
| 2023-03-24 | IMDC083501 | 0.828 ppm |
| 2023-03-24 | IMDC083502 | 0.466 ppm |
| 2023-03-24 | IMDC083504 | 0.685 ppm |
| 2023-05-15 | N254889 | 0.583 ppm |
| 2023-05-15 | N254890 | 0.860 ppm |
| 2023-05-15 | N254891 | 0.374 ppm |
| 2023-05-15 | N254892 | 0.645 ppm |
| 2023-05-15 | N254893 | 0.777 ppm |
| 2023-05-15 | I254894 | 0.371 ppm |
| 2023-07-25 | IMDG081701 | 0.555 ppm |
| 2023-07-25 | IMDG081703 | 0.582 ppm |
| 2023-07-25 | IMDG081705 | 0.705 ppm |
| 2023-11-30 | MDL001005 | 1.76 ppm |
| 2023-11-30 | MDL001003 | 0.778 ppm |
| 2023-11-30 | MDL001004 | 1.09 ppm |
| 2023-11-30 | MDL001001 | 0.779 ppm |
| 2023-12-13 | N263147 | 0.753 ppm |