Know Your Environment. Protect Your Health.

Chloroform

Clayton Water Supply Corporation Plant 3 and 7

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.

 

30

Samples

0

Samples exceeding legal limit (MCL)

15

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20184.20 ppb53ND - 8.70 ppb
20194.32 ppb551.96 ppb - 7.92 ppb
20205.34 ppb54ND - 8.16 ppb
2021ND50ND
20220.204 ppb51ND - 1.02 ppb
20232.35 ppb52ND - 6.43 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
2018-02-22Q18076150018.70 ppb
2018-05-24Q18209430018.36 ppb
2018-08-23Q1833946002ND
2018-08-23Q1833946008ND
2018-12-14Q18517840013.94 ppb
2019-02-05Q19052140011.96 ppb
2019-02-05Q19052140053.10 ppb
2019-04-30Q19172520013.15 ppb
2019-08-26Q19592710015.46 ppb
2019-12-17Q19803330017.92 ppb
2020-03-05Q20083420015.71 ppb
2020-03-05Q20083420058.16 ppb
2020-05-27Q20208390016.40 ppb
2020-09-22Q20375330016.42 ppb
2020-12-03Q2048553001ND
2021-02-24Q2104970001ND
2021-04-29Q2110985001ND
2021-09-28Q2126521006ND
2021-09-28Q2126521008ND
2021-12-02Q2133315001ND
2022-02-01Q2203638001ND
2022-04-12Q2211209001ND
2022-09-13Q2227119001ND
2022-11-03Q2233353003ND
2022-11-03Q22333530061.02 ppb
2023-02-16Q23065370015.33 ppb
2023-05-03Q23168000016.43 ppb
2023-07-27Q2330270001ND
2023-07-27Q2330270005ND
2023-10-17Q2344249001ND