Know Your Environment. Protect Your Health.

Chloroform

Lake Delton Waterworks

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.

 

20

Samples

0

Samples exceeding legal limit (MCL)

7

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20181.20 ppb111.20 ppb
20190.780 ppb220.360 ppb - 1.20 ppb
20200.235 ppb83ND - 1.10 ppb
20210.600 ppb21ND - 1.20 ppb
20220.760 ppb110.760 ppb
20230.233 ppb61ND - 1.40 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
2018-07-1810683561.20 ppb
2019-07-2211359811.20 ppb
2019-12-1011648220.360 ppb
2020-04-20409868ND
2020-05-28424672ND
2020-05-28424675ND
2020-05-28424681ND
2020-06-02426799ND
2020-06-024267860.360 ppb
2020-06-024267890.420 ppb
2020-07-084427871.10 ppb
2021-01-20526112ND
2021-07-2010277861.20 ppb
2022-07-1411638750.760 ppb
2023-03-201301274ND
2023-03-201301276ND
2023-04-191316618ND
2023-04-201316620ND
2023-04-201316622ND
2023-07-1713492671.40 ppb