Nitrate and nitrite
Oklahoma University
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 | 0.354 ppm | 27 | 24 | ND - 0.758 ppm |
| 2019 | 0.399 ppm | 28 | 27 | ND - 0.721 ppm |
| 2020 | 0.428 ppm | 27 | 27 | 0.202 ppm - 0.830 ppm |
| 2021 | 0.382 ppm | 35 | 35 | 0.188 ppm - 0.905 ppm |
| 2022 | 0.392 ppm | 31 | 31 | 0.135 ppm - 0.910 ppm |
| 2023 | 0.521 ppm | 13 | 13 | 0.255 ppm - 0.886 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 |
|---|