Nitrate and nitrite
New London Department of Public Utilities
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 | 0.0765 ppm | 2 | 2 | 0.0650 ppm - 0.0880 ppm |
| 2019 | 0.0235 ppm | 2 | 2 | 0.0230 ppm - 0.0240 ppm |
| 2020 | 0.0285 ppm | 2 | 2 | 0.0230 ppm - 0.0340 ppm |
| 2021 | 0.0265 ppm | 2 | 2 | 0.0220 ppm - 0.0310 ppm |
| 2022 | 0.0300 ppm | 2 | 1 | ND - 0.0600 ppm |
| 2023 | 0.0240 ppm | 2 | 1 | ND - 0.0480 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 |
|---|---|---|
| 2018-11-29 | 28422NOX | 0.0880 ppm |
| 2018-11-29 | 28425IOCR | 0.0650 ppm |
| 2019-11-20 | 30475NOX | 0.0240 ppm |
| 2019-11-20 | 30469IOCR | 0.0230 ppm |
| 2020-12-01 | 32748NOX | 0.0340 ppm |
| 2020-12-01 | 32743IOCR | 0.0230 ppm |
| 2021-10-27 | 34803NOX | 0.0310 ppm |
| 2021-10-27 | 34800IOCR | 0.0220 ppm |
| 2022-09-15 | 36584NOX | 0.0600 ppm |
| 2022-09-15 | 36581IOCR | ND |
| 2023-09-14 | 38754NOX | 0.0480 ppm |
| 2023-09-14 | 38758IOCR | ND |