Know Your Environment. Protect Your Health.

Chloroform

Gig Harbor Water Department

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.

 

36

Samples

0

Samples exceeding legal limit (MCL)

16

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.465 ppb43ND - 1.01 ppb
20190.286 ppb145ND - 1.25 ppb
2020N/A00N/A
20210.0878 ppb91ND - 0.790 ppb
20221.66 ppb54ND - 3.12 ppb
20232.47 ppb440.770 ppb - 3.61 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
2018-08-081.01 ppb
2018-08-080.500 ppb
2018-08-080.350 ppb
2018-08-08ND
2019-03-21ND
2019-05-13ND
2019-05-13ND
2019-05-13ND
2019-05-13ND
2019-05-13ND
2019-08-081.13 ppb
2019-08-080.520 ppb
2019-08-081.25 ppb
2019-08-080.530 ppb
2019-08-220.570 ppb
2019-08-22ND
2019-08-22ND
2019-08-22ND
2021-08-034159321ND
2021-08-034159322ND
2021-08-034159323ND
2021-08-0341593200.790 ppb
2021-08-174163791ND
2021-08-174163793ND
2021-08-174163798ND
2021-08-174163792ND
2021-08-174163790ND
2022-08-0943386813.12 ppb
2022-08-0943386781.94 ppb
2022-08-0943386760.790 ppb
2022-08-0943386742.47 ppb
2022-09-194363148ND
2023-08-0745057590.770 ppb
2023-08-0745057603.18 ppb
2023-08-0745057613.61 ppb
2023-08-0745057622.32 ppb