Nitrate and nitrite
Tualatin Valley 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 | 0.458 ppm | 3 | 3 | 0.280 ppm - 0.591 ppm |
| 2019 | 0.521 ppm | 1 | 1 | 0.521 ppm |
| 2020 | 0.326 ppm | 6 | 4 | ND - 0.561 ppm |
| 2021 | ND | 1 | 0 | ND |
| 2022 | ND | 1 | 0 | ND |
| 2023 | 0.610 ppm | 1 | 1 | 0.610 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 |
|---|---|---|
| 2018-06-18 | 816903001-I | 0.591 ppm |
| 2018-09-17 | 826001901-I | 0.280 ppm |
| 2018-11-07 | 831111301-I | 0.503 ppm |
| 2019-10-01 | 927402701-I | 0.521 ppm |
| 2020-01-21 | 002104103-I | 0.529 ppm |
| 2020-02-25 | 005603501-I | 0.561 ppm |
| 2020-04-17 | 010801201-I | ND |
| 2020-08-26 | 023903501-I | 0.470 ppm |
| 2020-09-23 | 026703501-I | ND |
| 2020-11-04 | 030901101-I | 0.398 ppm |
| 2021-05-13 | 113302201-I | ND |
| 2022-07-25 | 2206015-01-I | ND |
| 2023-09-26 | 23-58713 | 0.610 ppm |