Nitrate and nitrite
CTWC - Unionville 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 | 1.32 ppm | 6 | 6 | 0.460 ppm - 2.40 ppm |
| 2019 | 1.77 ppm | 4 | 4 | 1.18 ppm - 2.06 ppm |
| 2020 | 1.55 ppm | 3 | 3 | 0.484 ppm - 2.38 ppm |
| 2021 | 1.68 ppm | 3 | 3 | 0.778 ppm - 2.30 ppm |
| 2022 | 1.42 ppm | 3 | 3 | 0.580 ppm - 2.60 ppm |
| 2023 | 1.63 ppm | 3 | 3 | 0.870 ppm - 2.60 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 |
|---|---|---|
| 2018-04-10 | CA16951NOX | 1.79 ppm |
| 2018-04-10 | CA16950NOX | 1.67 ppm |
| 2018-07-23 | CA96742 | 0.460 ppm |
| 2018-07-23 | CA96743 | 2.40 ppm |
| 2018-11-06 | NOX 200511903 | 0.702 ppm |
| 2018-11-14 | IOC1 200512788 | 0.890 ppm |
| 2019-02-05 | NOX 200520747 | 1.99 ppm |
| 2019-02-05 | NOX 200520746 | 1.84 ppm |
| 2019-09-17 | NOX 200549386 | 2.06 ppm |
| 2019-09-17 | NOX 200549392 | 1.18 ppm |
| 2020-07-07 | NOX 200581835 | 2.38 ppm |
| 2020-07-07 | NOX 200581836 | 0.484 ppm |
| 2020-10-19 | NOX 200594470 | 1.77 ppm |
| 2021-03-02 | NOX 200608358 | 2.30 ppm |
| 2021-03-02 | NOX 200608357 | 1.97 ppm |
| 2021-09-22 | 300073532 300073533 | 0.778 ppm |
| 2022-03-14 | CK86780 | 0.580 ppm |
| 2022-03-14 | CK86779 | 1.07 ppm |
| 2022-08-23 | CM11959 | 2.60 ppm |
| 2023-01-24 | CN29187 | 2.60 ppm |
| 2023-01-24 | CN29186 | 1.41 ppm |
| 2023-08-01 | CO63104 | 0.870 ppm |