Arsenic
Connecticut Water Company - Northern Region-Western System
Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.
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 | ND | 5 | 0 | ND |
| 2019 | ND | 2 | 0 | ND |
| 2020 | ND | 3 | 0 | ND |
| 2021 | ND | 2 | 0 | ND |
| 2022 | 1.08 ppb | 5 | 3 | ND - 4.00 ppb |
| 2023 | 0.180 ppb | 5 | 1 | ND - 0.900 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.004 ppb
The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
EPA Maximum Contaminant
Level (MCL): 10 ppb
The legal limit for arsenic, established in 2001, was based on costs for arsenic removal, as calculated at the time that the standard was set. This limit does not fully protect against the risk of cancer due to arsenic exposure.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-23 | BZ78887IOC1 | ND |
| 2018-01-31 | BZ82691IOCR | ND |
| 2018-03-02 | BZ97488IOC1 | ND |
| 2018-07-12 | CA89150 | ND |
| 2018-07-13 | CA89903 | ND |
| 2019-01-10 | IOCR 200518412 | ND |
| 2019-01-15 | IOC1 200518779 | ND |
| 2020-01-09 | IOC1 200562368 | ND |
| 2020-01-15 | IOCR 200563111 | ND |
| 2020-09-21 | IOC1 200591023 | ND |
| 2021-02-17 | IOC1 200607102 | ND |
| 2021-03-05 | IOCR 200608709 | ND |
| 2022-01-24 | CK22294 | 0.900 ppb |
| 2022-01-25 | CK23176 | ND |
| 2022-02-01 | CK27430 | ND |
| 2022-02-01 | CK27434 | 0.500 ppb |
| 2022-02-16 | CK69357 | 4.00 ppb |
| 2023-01-11 | CN20957 | ND |
| 2023-01-18 | CN25096 | ND |
| 2023-08-23 | CO81672 | ND |
| 2023-10-31 | CP38331 | ND |
| 2023-12-13 | CP67269 | 0.900 ppb |