Nitrate and nitrite
Annapolis PWS
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 | 0.220 ppm | 2 | 2 | 0.200 ppm - 0.240 ppm |
| 2019 | 0.142 ppm | 2 | 2 | 0.0740 ppm - 0.210 ppm |
| 2020 | 0.103 ppm | 2 | 2 | 0.102 ppm - 0.103 ppm |
| 2021 | 0.210 ppm | 2 | 2 | 0.193 ppm - 0.226 ppm |
| 2022 | 0.0525 ppm | 2 | 2 | 0.0470 ppm - 0.0580 ppm |
| 2023 | 0.0930 ppm | 2 | 2 | 0.0890 ppm - 0.0970 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 |
|---|---|---|
| 2018-07-10 | AD29393 | 0.200 ppm |
| 2018-07-10 | AD29394 | 0.240 ppm |
| 2019-07-23 | AD52084 | 0.0740 ppm |
| 2019-07-23 | AD52085 | 0.210 ppm |
| 2020-07-27 | 2011669 | 0.102 ppm |
| 2020-07-27 | 2011670 | 0.103 ppm |
| 2021-07-19 | 2113682 | 0.193 ppm |
| 2021-07-19 | 2113683 | 0.226 ppm |
| 2022-07-12 | 2214771 | 0.0470 ppm |
| 2022-07-12 | 2214772 | 0.0580 ppm |
| 2023-07-19 | 2311680 | 0.0890 ppm |
| 2023-07-19 | 2311679 | 0.0970 ppm |