Chloroform
City of Spokane
Chloroform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Chloroform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Read More.
In addition to tap water disinfection, chloroform pollution in the environment also comes from industrial discharges from pulp and paper mills, and from urban wastewater effluent. Human studies show that chloroform damages the kidneys, liver and central nervous system. In animals, chloroform causes infertility, birth defects and cancer.
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 | 0.244 ppb | 11 | 5 | ND - 0.760 ppb |
| 2019 | 0.106 ppb | 18 | 3 | ND - 0.750 ppb |
| 2020 | N/A | 0 | 0 | N/A |
| 2021 | 0.193 ppb | 11 | 5 | ND - 0.590 ppb |
| 2022 | 0.292 ppb | 10 | 8 | ND - 0.530 ppb |
| 2023 | 0.199 ppb | 10 | 5 | ND - 0.600 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.4 ppb
The EWG Health Guideline of 0.4 ppb for chloroform was based on the California Office of Environmental Health Hazard Assessment's public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer and harm to fetal growth and development.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-30 | ND | |
| 2018-01-30 | 0.380 ppb | |
| 2018-01-30 | ND | |
| 2018-01-30 | 0.470 ppb | |
| 2018-05-10 | ND | |
| 2018-05-10 | 0.500 ppb | |
| 2018-07-17 | ND | |
| 2018-07-17 | ND | |
| 2018-07-17 | ND | |
| 2018-11-08 | 0.760 ppb | |
| 2018-11-08 | 0.570 ppb | |
| 2019-02-14 | ND | |
| 2019-02-14 | ND | |
| 2019-05-09 | ND | |
| 2019-05-09 | ND | |
| 2019-07-23 | ND | |
| 2019-07-23 | ND | |
| 2019-07-26 | ND | |
| 2019-07-26 | ND | |
| 2019-07-26 | 0.580 ppb | |
| 2019-07-26 | ND | |
| 2019-07-26 | ND | |
| 2019-07-26 | ND | |
| 2019-07-26 | ND | |
| 2019-07-26 | ND | |
| 2019-08-08 | ND | |
| 2019-08-08 | ND | |
| 2019-11-13 | 0.750 ppb | |
| 2019-11-13 | 0.570 ppb | |
| 2021-01-26 | 4066970 | ND |
| 2021-01-26 | 4066969 | ND |
| 2021-02-09 | 4097358 | ND |
| 2021-02-09 | 4097356 | 0.590 ppb |
| 2021-05-13 | 4115289 | 0.370 ppb |
| 2021-05-13 | 4115288 | ND |
| 2021-07-27 | 4195356 | ND |
| 2021-08-11 | 4159815 | 0.200 ppb |
| 2021-08-11 | 4159816 | ND |
| 2021-11-10 | 4203831 | 0.530 ppb |
| 2021-11-10 | 4203830 | 0.430 ppb |
| 2022-02-10 | 4244095 | 0.300 ppb |
| 2022-02-10 | 4244094 | 0.370 ppb |
| 2022-05-12 | 4282305 | 0.430 ppb |
| 2022-05-12 | 4282306 | 0.260 ppb |
| 2022-07-26 | 4319391 | ND |
| 2022-07-26 | 4319393 | ND |
| 2022-08-11 | 4327017 | 0.260 ppb |
| 2022-08-11 | 4327016 | 0.270 ppb |
| 2022-11-10 | 4373002 | 0.530 ppb |
| 2022-11-10 | 4373001 | 0.500 ppb |
| 2023-01-24 | 4399432 | ND |
| 2023-02-09 | 4424701 | 0.290 ppb |
| 2023-02-09 | 4424700 | 0.340 ppb |
| 2023-05-10 | 4452949 | ND |
| 2023-05-10 | 4452948 | ND |
| 2023-07-25 | 4507772 | ND |
| 2023-08-03 | 4498819 | 0.230 ppb |
| 2023-08-03 | 4498818 | ND |
| 2023-11-09 | 4547610 | 0.600 ppb |
| 2023-11-09 | 4547611 | 0.530 ppb |