Nitrate and nitrite
Mill River Water District
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.
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 | 0.0900 ppm | 1 | 1 | 0.0900 ppm |
| 2019 | 0.199 ppm | 2 | 2 | 0.0810 ppm - 0.317 ppm |
| 2020 | ND | 1 | 0 | ND |
| 2021 | 0.177 ppm | 2 | 1 | ND - 0.353 ppm |
| 2022 | 0.110 ppm | 1 | 1 | 0.110 ppm |
| 2023 | 0.0912 ppm | 2 | 2 | 0.0633 ppm - 0.119 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
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2022-11-02 | AY19818-NIT | 0.110 ppm |
| 2023-05-22 | AZ09224-NIT | 0.119 ppm |
| 2023-10-17 | AZ19164-NIT | 0.0633 ppm |