Know Your Environment. Protect Your Health.

Chloroform

Western Hills Water System

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.

Click here to read more about disinfection byproducts.

 

31

Samples

0

Samples exceeding legal limit (MCL)

4

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND50ND
20190.240 ppb51ND - 1.20 ppb
20201.40 ppb51ND - 7.00 ppb
202123.8 ppb61ND - 143.0 ppb
20220.380 ppb51ND - 1.90 ppb
2023ND50ND

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
2018-09-18AE40729ND
2018-09-18AE40735ND
2018-09-18AE40745ND
2018-09-18AE40749ND
2018-09-18AE40707ND
2019-06-17AE71118ND
2019-06-17AE71138ND
2019-06-17AE71098ND
2019-06-17AE710901.20 ppb
2019-06-17AE71069ND
2020-06-15AF15203ND
2020-06-15AF15206ND
2020-06-15AF152087.00 ppb
2020-06-15AF15210ND
2020-06-15AF15214ND
2021-08-03AF64437ND
2021-08-03AF64455143.0 ppb
2021-08-03AF64451ND
2021-08-03AF64447ND
2021-09-23AF71029ND
2021-10-14AF73603ND
2022-03-22AF90050ND
2022-03-22AF90052ND
2022-03-22AF90054ND
2022-06-07AF99862ND
2022-10-04AG159201.90 ppb
2023-07-12AG48148ND
2023-07-12AG48162ND
2023-07-12AG48172ND
2023-07-12AG48178ND
2023-07-12AG48180ND