Nitrate and nitrite
Aquarion Water Company of Connecticut - Main System
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 | 0.560 ppm | 8 | 8 | 0.0880 ppm - 1.29 ppm |
| 2019 | 0.598 ppm | 8 | 8 | 0.167 ppm - 1.34 ppm |
| 2020 | 0.557 ppm | 8 | 8 | 0.121 ppm - 1.28 ppm |
| 2021 | 0.588 ppm | 8 | 8 | 0.0900 ppm - 1.33 ppm |
| 2022 | 0.482 ppm | 8 | 5 | ND - 1.60 ppm |
| 2023 | 0.503 ppm | 8 | 5 | ND - 1.56 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 |
|---|---|---|
| 2018-02-05 | 201801570-NOX | 0.337 ppm |
| 2018-02-05 | 201801586-NOX | 0.0930 ppm |
| 2018-02-05 | 201801587-IOCR | 0.0880 ppm |
| 2018-02-05 | 201801571-IOCR | 0.332 ppm |
| 2018-02-05 | 201801603-IOCR | 0.632 ppm |
| 2018-02-05 | 201801604-NOX | 0.599 ppm |
| 2018-07-05 | 201809662-NOX | 1.11 ppm |
| 2018-07-05 | 201809658-NOX | 1.29 ppm |
| 2019-02-04 | 201901553-IOCR | 0.550 ppm |
| 2019-02-04 | 201901582-IOCR | 0.396 ppm |
| 2019-02-04 | 201901614-IOCR | 0.177 ppm |
| 2019-02-04 | 201901613-NOX | 0.167 ppm |
| 2019-02-04 | 201901581-NOX | 0.378 ppm |
| 2019-02-04 | 201901554-NOX | 0.523 ppm |
| 2019-07-01 | 201909695-NOX | 1.26 ppm |
| 2019-07-01 | 201909693-NOX | 1.34 ppm |
| 2020-02-03 | 202001681-NOX | 0.600 ppm |
| 2020-02-03 | 202001624-NOX | 0.326 ppm |
| 2020-02-03 | 202001640-NOX | 0.123 ppm |
| 2020-02-03 | 202001641-IOCR | 0.121 ppm |
| 2020-02-03 | 202001625-IOCR | 0.304 ppm |
| 2020-02-03 | 202001680-IOCR | 0.589 ppm |
| 2020-07-07 | 202010259-NOX | 1.11 ppm |
| 2020-07-07 | 202010253-NOX | 1.28 ppm |
| 2021-02-02 | 202101448-NOX | 0.684 ppm |
| 2021-02-02 | 202101447-IOCR | 0.680 ppm |
| 2021-02-02 | 202101395-IOCR | 0.342 ppm |
| 2021-02-02 | 202101406-NOX | 0.111 ppm |
| 2021-02-02 | 202101394-NOX | 0.355 ppm |
| 2021-02-02 | 202101407-IOCR | 0.0900 ppm |
| 2021-07-06 | 202110289-NOX | 1.12 ppm |
| 2021-07-06 | 202110283-NOX | 1.33 ppm |
| 2022-02-07 | 202202089-IOCR | ND |
| 2022-02-07 | 202202023-IOCR | ND |
| 2022-02-07 | 202202034-IOCR | ND |
| 2022-02-07 | 202202033-NOX | 0.127 ppm |
| 2022-02-07 | 202202022-NOX | 0.287 ppm |
| 2022-02-07 | 202202090-NOX | 0.477 ppm |
| 2022-07-05 | 202210995-NOX | 1.37 ppm |
| 2022-07-05 | 202210989-NOX | 1.60 ppm |
| 2023-02-06 | 202301854-NOX | 0.565 ppm |
| 2023-02-06 | 202301775-NOX | 0.0690 ppm |
| 2023-02-06 | 202301771-IOCR | ND |
| 2023-02-06 | 202301853-IOCR | ND |
| 2023-02-09 | 202302139-NOX | 0.418 ppm |
| 2023-02-09 | 202302140-IOCR | ND |
| 2023-06-07 | 202309441-NOX | 1.42 ppm |
| 2023-06-07 | 202309440-NOX | 1.56 ppm |