Chloroform
Erwin Utilities
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 |
|---|---|---|---|---|
| 2014 | 0.877 ppb | 4 | 4 | 0.767 ppb - 1.08 ppb |
| 2015 | 1.07 ppb | 4 | 4 | 0.899 ppb - 1.31 ppb |
| 2016 | 0.511 ppb | 6 | 3 | ND - 1.35 ppb |
| 2017 | 0.385 ppb | 7 | 3 | ND - 1.30 ppb |
| 2018 | 0.849 ppb | 4 | 4 | 0.754 ppb - 0.945 ppb |
| 2019 | 0.964 ppb | 4 | 4 | 0.894 ppb - 1.03 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.4 ppb
The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.
ppb = parts per billion
All test results
| Date | Result |
|---|---|
| 2014-02-28 | 0.767 ppb |
| 2014-05-13 | 0.818 ppb |
| 2014-08-07 | 1.08 ppb |
| 2014-11-12 | 0.844 ppb |
| 2015-02-11 | 0.899 ppb |
| 2015-04-23 | 1.31 ppb |
| 2015-08-20 | 0.973 ppb |
| 2015-11-19 | 1.10 ppb |
| 2016-02-03 | 0.805 ppb |
| 2016-09-07 | ND |
| 2016-09-07 | ND |
| 2016-09-07 | ND |
| 2016-09-23 | 1.35 ppb |
| 2016-11-16 | 0.908 ppb |
| 2017-02-14 | ND |
| 2017-05-18 | 1.30 ppb |
| 2017-08-16 | 0.596 ppb |
| 2017-12-12 | ND |
| 2017-12-12 | ND |
| 2017-12-12 | 0.802 ppb |
| 2017-12-12 | ND |
| 2018-02-22 | 0.834 ppb |
| 2018-06-13 | 0.862 ppb |
| 2018-08-02 | 0.945 ppb |
| 2018-10-23 | 0.754 ppb |
| 2019-03-12 | 1.03 ppb |
| 2019-05-08 | 0.967 ppb |
| 2019-08-13 | 0.964 ppb |
| 2019-12-12 | 0.894 ppb |