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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

Harris County MUD 165

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.

 

26

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012N/A00N/A
2013ND30ND
2014ND40ND
2015ND90ND
2016ND50ND
2017ND50ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.4 ppb

The EWG Health Guideline of 0.4 ppb for chloroform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

ppb = parts per billion

All test results

Date Lab ID Result
2013-06-13AC22099ND
2013-06-13AC22029ND
2013-06-13AC22097ND
2014-07-16AC59896ND
2014-07-16AC59890ND
2014-07-16AC59843ND
2014-07-16AC59847ND
2015-05-27AC93492ND
2015-05-27AC93485ND
2015-05-27AC93425ND
2015-05-27AC93397ND
2015-05-27AC93395ND
2015-09-09AD06257ND
2015-09-09AD06255ND
2015-11-10AD13188ND
2015-11-10AD13186ND
2016-03-21AD29673ND
2016-03-21AD29633ND
2016-03-21AD29639ND
2016-09-26AD51032ND
2016-09-26AD51035ND
2017-05-04AD82733ND
2017-05-04AD82713ND
2017-05-04AD82785ND
2017-05-04AD82787ND
2017-05-04AD82793ND