Know Your Environment. Protect Your Health.

Chloroform

City of Thornton 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.

 

12

Samples

0

Samples exceeding legal limit (MCL)

4

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20181.13 ppb21ND - 2.26 ppb
20191.34 ppb21ND - 2.68 ppb
2020ND20ND
2021ND20ND
20221.97 ppb21ND - 3.94 ppb
20230.640 ppb21ND - 1.28 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
2018-06-28Q1825968002ND
2018-06-28Q18259680092.26 ppb
2019-06-27Q1940534002ND
2019-06-27Q19405340052.68 ppb
2020-06-09Q2023459001ND
2020-06-09Q2023459005ND
2021-05-06Q2111812003ND
2021-05-06Q2111812009ND
2022-08-22Q2224810001ND
2022-08-22Q22248100053.94 ppb
2023-07-24Q23292280011.28 ppb
2023-10-18Q2344550001ND