Know Your Environment. Protect Your Health.

Chloroform

City of Washougal

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.

 

15

Samples

0

Samples exceeding legal limit (MCL)

7

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.355 ppb21ND - 0.710 ppb
20190.513 ppb32ND - 0.950 ppb
2020N/A00N/A
20210.670 ppb42ND - 1.90 ppb
20220.423 ppb62ND - 1.60 ppb
2023N/A00N/A

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
2018-12-18ND
2018-12-180.710 ppb
2019-05-07ND
2019-12-100.950 ppb
2019-12-100.590 ppb
2021-05-174118751ND
2021-06-234136257ND
2021-12-0742184010.780 ppb
2021-12-0742184021.90 ppb
2022-09-084359902ND
2022-09-084359900ND
2022-09-084359904ND
2022-11-084374608ND
2022-12-1943924220.940 ppb
2022-12-1943924231.60 ppb