Know Your Environment. Protect Your Health.

Chloroform

West Harris County Municipal Utility District 11

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.

 

14

Samples

0

Samples exceeding legal limit (MCL)

5

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND20ND
20191.55 ppb221.30 ppb - 1.80 ppb
2020ND30ND
2021ND20ND
20220.600 ppb21ND - 1.20 ppb
20231.000 ppb32ND - 1.60 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
2018-01-29AE10992ND
2018-05-18AE26988ND
2019-02-20AE550571.80 ppb
2019-05-08AE653931.30 ppb
2020-06-17AF15785ND
2020-06-17AF15824ND
2020-06-17AF15826ND
2021-07-27AF63523ND
2021-07-27AF63558ND
2022-06-29AG027441.20 ppb
2022-06-29AG02823ND
2023-05-18AG410171.40 ppb
2023-05-18AG411201.60 ppb
2023-05-18AG41122ND