Chloroform
Amawalk-shenorock Water District
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 | 24.8 ppb | 8 | 8 | 13.9 ppb - 36.3 ppb |
| 2015 | 29.0 ppb | 8 | 8 | 13.9 ppb - 37.9 ppb |
| 2016 | 26.0 ppb | 8 | 8 | 19.4 ppb - 35.8 ppb |
| 2017 | 34.9 ppb | 8 | 8 | 24.9 ppb - 46.0 ppb |
| 2018 | 35.7 ppb | 10 | 10 | 29.3 ppb - 39.2 ppb |
| 2019 | 30.4 ppb | 8 | 8 | 18.6 ppb - 38.5 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 | Lab ID | Result |
|---|---|---|
| 2014-01-16 | AQ00910DBP | 13.9 ppb |
| 2014-01-16 | AQ00909DBP | 20.3 ppb |
| 2014-05-19 | AQ09150DBP | 36.3 ppb |
| 2014-05-19 | AQ09149DBP | 14.3 ppb |
| 2014-08-18 | AQ17044DBP | 26.4 ppb |
| 2014-08-18 | AQ17043DBP | 31.7 ppb |
| 2014-11-19 | AQ23911 DBP | 20.6 ppb |
| 2014-11-19 | AQ23910 DBP | 35.1 ppb |
| 2015-01-26 | AR01735 DBP | 15.6 ppb |
| 2015-01-26 | AR01734 DBP | 13.9 ppb |
| 2015-05-18 | AR10117 DBP | 34.7 ppb |
| 2015-05-18 | AR10116 DBP | 34.1 ppb |
| 2015-08-19 | 420-94174-2 DBP | 34.0 ppb |
| 2015-08-19 | 420-94174-1 DBP | 31.0 ppb |
| 2015-11-16 | AR24505 DBP | 37.9 ppb |
| 2015-11-16 | AR24504 DBP | 31.1 ppb |
| 2016-01-20 | AS01178 DBP | 25.6 ppb |
| 2016-01-20 | AS01177 DBP | 22.3 ppb |
| 2016-05-17 | AS10140 DBP | 30.4 ppb |
| 2016-05-17 | AS10139 DBP | 19.4 ppb |
| 2016-08-17 | AS17753 DBP | 35.8 ppb |
| 2016-08-17 | AS17754 DBP | 33.7 ppb |
| 2016-11-16 | AS24348 DBP | 20.3 ppb |
| 2016-11-16 | AS24347 DBP | 20.7 ppb |
| 2017-02-15 | AT03050 DBP | 26.8 ppb |
| 2017-02-15 | AT03051 DBP | 24.9 ppb |
| 2017-05-08 | AT08941-DBP2 | 31.3 ppb |
| 2017-05-08 | AT08942-DBP2 | 31.6 ppb |
| 2017-08-15 | AT17188-DBP2 | 31.7 ppb |
| 2017-08-15 | AT17189-DBP2 | 42.3 ppb |
| 2017-11-15 | AT24047-DBP2 | 44.6 ppb |
| 2017-11-15 | AT24048-DBP2 | 46.0 ppb |
| 2018-02-12 | AU02917 DBP2 | 38.9 ppb |
| 2018-02-12 | AU2918 DBP2 | 36.5 ppb |
| 2018-02-12 | AU02917-DBP2 | 38.9 ppb |
| 2018-02-12 | AU02918-DBP2 | 36.5 ppb |
| 2018-05-08 | AU09380-DBP2 | 31.8 ppb |
| 2018-05-08 | AU09381-DBP2 | 32.4 ppb |
| 2018-08-13 | AU17300-DBP2 | 38.1 ppb |
| 2018-08-13 | AU17296-DBP2 | 35.0 ppb |
| 2018-11-13 | AU24507-DBP2 | 39.2 ppb |
| 2018-11-13 | AU24506-DBP2 | 29.3 ppb |
| 2019-02-12 | AV02992-DBP2 | 32.1 ppb |
| 2019-02-12 | AV02993-DBP2 | 30.8 ppb |
| 2019-05-08 | AV09342DBP2 | 18.6 ppb |
| 2019-05-08 | AV09343DBP2 | 38.5 ppb |
| 2019-08-08 | AV16847-DBP2 | 28.4 ppb |
| 2019-08-08 | AV16848-DBP2 | 32.9 ppb |
| 2019-11-12 | AV23857-DBP2 | 32.1 ppb |
| 2019-11-12 | AV23856-DBP2 | 29.8 ppb |