Nitrate
North Castle Water District #4
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 | 0.560 ppm | 2 | 2 | 0.181 ppm - 0.939 ppm |
| 2019 | 0.713 ppm | 2 | 2 | 0.145 ppm - 1.28 ppm |
| 2020 | 0.582 ppm | 6 | 5 | ND - 1.16 ppm |
| 2021 | 0.455 ppm | 6 | 4 | ND - 1.54 ppm |
| 2022 | 0.621 ppm | 6 | 6 | 0.106 ppm - 1.62 ppm |
| 2023 | 0.438 ppm | 6 | 6 | 0.0796 ppm - 1.38 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 |
|---|---|---|
| 2018-07-24 | AU15718-NIT | 0.939 ppm |
| 2018-07-24 | AU15716-INT | 0.181 ppm |
| 2019-08-05 | AV16474-NIT | 0.145 ppm |
| 2019-08-05 | AV16471-NIT | 1.28 ppm |
| 2020-02-25 | AW03861-NIT | 0.166 ppm |
| 2020-02-25 | AW03855-NIT | 0.163 ppm |
| 2020-02-25 | AW03853-NIT | 1.16 ppm |
| 2020-07-13 | AW13180-NIT | 1.000 ppm |
| 2020-07-29 | AW14499-NIT | 1.000 ppm |
| 2020-08-27 | AW16635-NIT | ND |
| 2021-03-02 | AX04052-NIT | 1.000 ppm |
| 2021-03-03 | AX04226-NIT | ND |
| 2021-03-03 | AX04224-NIT | ND |
| 2021-07-06 | AX13097-NIT | 0.0615 ppm |
| 2021-08-03 | AX15569-NIT | 0.129 ppm |
| 2021-08-03 | AX15556-NIT | 1.54 ppm |
| 2022-03-01 | AY03622-NIT | 1.62 ppm |
| 2022-03-01 | AY03616-NIT | 0.159 ppm |
| 2022-03-01 | AY03618-NIT | 0.151 ppm |
| 2022-07-19 | AY12490-NIT | 0.140 ppm |
| 2022-07-20 | AY12624-NIT | 1.55 ppm |
| 2022-07-21 | AY12753-NIT | 0.106 ppm |
| 2023-03-21 | AZ05017-NIT | 0.113 ppm |
| 2023-03-21 | AZ05015-NIT | 0.116 ppm |
| 2023-03-22 | AZ05102-NIT | 1.38 ppm |
| 2023-07-10 | AZ12341-NIT | 0.0796 ppm |
| 2023-07-10 | AZ12342-NIT | 0.745 ppm |
| 2023-07-25 | AZ13469-NIT | 0.194 ppm |