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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Golden State Water Company (GSWC) - South San Gabriel

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.

MORE ABOUT THIS CONTAMINANT

 

107

Samples

0

Samples exceeding legal limit (MCL)

12

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20140.0875 ppb161ND - 1.40 ppb
20150.213 ppb162ND - 2.20 ppb
20160.0370 ppb271ND - 1.000 ppb
20170.0688 ppb161ND - 1.10 ppb
20181.61 ppb167ND - 6.00 ppb
2019ND160ND

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
2014-01-239588-800-0920ND
2014-01-239588-801-0940ND
2014-01-239588-802-0910ND
2014-01-239588-803-0930ND
2014-04-229588-800-0925ND
2014-04-229588-801-0935ND
2014-04-229588-802-0900ND
2014-04-229588-803-09101.40 ppb
2014-07-239588-800-1215ND
2014-07-239588-801-1145ND
2014-07-239588-802-1200ND
2014-07-239588-803-1225ND
2014-10-239588-800-0940ND
2014-10-239588-801-0920ND
2014-10-239588-802-0950ND
2014-10-239588-803-0930ND
2015-01-239588-800-0900ND
2015-01-239588-801-0915ND
2015-01-239588-802-0840ND
2015-01-239588-803-0850ND
2015-04-229588-800-0855ND
2015-04-229588-801-0915ND
2015-04-229588-802-0905ND
2015-04-229588-803-0845ND
2015-07-239588-800-0900ND
2015-07-239588-801-0920ND
2015-07-239588-802-0910ND
2015-07-239588-803-08502.20 ppb
2015-10-269588-800-0905ND
2015-10-269588-801-0915ND
2015-10-269588-802-0845ND
2015-10-269588-803-08551.20 ppb
2016-01-269588-800-0920ND
2016-01-269588-801-0930ND
2016-01-269588-802-0900ND
2016-01-269588-803-0910ND
2016-02-102706-046-1234ND
2016-03-092706-046-1040ND
2016-04-112706-046-1413ND
2016-04-229588-800-0900ND
2016-04-229588-801-0920ND
2016-04-229588-802-0910ND
2016-04-229588-803-0850ND
2016-05-122706-046-1239ND
2016-06-202706-046-1345ND
2016-07-112706-046-1047ND
2016-07-269588-800-0855ND
2016-07-269588-801-0925ND
2016-07-269588-802-0910ND
2016-07-269588-803-0845ND
2016-08-080007-046-1427ND
2016-09-122706-046-1426ND
2016-10-102706-046-1217ND
2016-10-269588-800-0925ND
2016-10-269588-801-0945ND
2016-10-269588-802-0935ND
2016-10-269588-803-09151.000 ppb
2016-11-072706-046-1228ND
2016-12-152706-046-1108ND
2017-01-249588-800-0915ND
2017-01-249588-801-0935ND
2017-01-249588-802-0925ND
2017-01-249588-803-0905ND
2017-04-249588-800-1030ND
2017-04-249588-801-1005ND
2017-04-249588-802-1015ND
2017-04-249588-803-1040ND
2017-07-279588-800-1015ND
2017-07-279588-801-0945ND
2017-07-279588-802-1000ND
2017-07-279588-803-1025ND
2017-10-249588-800-0900ND
2017-10-249588-801-0925ND
2017-10-249588-802-0910ND
2017-10-249588-803-08501.10 ppb
2018-01-249588-800-09201.50 ppb
2018-01-249588-801-0940ND
2018-01-249588-802-0930ND
2018-01-249588-803-0910ND
2018-04-249588-800-0900ND
2018-04-249588-801-0920ND
2018-04-249588-802-0910ND
2018-04-249588-803-0850ND
2018-07-249588-800-08405.90 ppb
2018-07-249588-801-09005.70 ppb
2018-07-249588-802-08501.60 ppb
2018-07-249588-803-08306.00 ppb
2018-10-239588-800-08502.00 ppb
2018-10-239588-801-0910ND
2018-10-239588-802-0900ND
2018-10-239588-803-08453.10 ppb
2019-01-249588-800-0955ND
2019-01-249588-801-1005ND
2019-01-249588-802-0930ND
2019-01-249588-803-0945ND
2019-04-239588-800-0855ND
2019-04-239588-801-0915ND
2019-04-239588-802-0905ND
2019-04-239588-803-0845ND
2019-07-239588-800-0845ND
2019-07-239588-801-0855ND
2019-07-239588-802-0820ND
2019-07-239588-803-0835ND
2019-10-239588-800-0855ND
2019-10-239588-801-0925ND
2019-10-239588-802-0910ND
2019-10-239588-803-0845ND