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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

Los Angeles County Waterworks District 36-Val Verde

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)

18

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND10ND
2013ND30ND
20140.336 ppb95ND - 0.740 ppb
20150.317 ppb94ND - 0.810 ppb
20160.533 ppb96ND - 1.07 ppb
20170.778 ppb53ND - 1.46 ppb

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
2012-05-095442-012-0937ND
2013-05-025442-012-0918ND
2013-10-095442-800-1031ND
2013-10-095442-801-1244ND
2014-01-085442-800-1210ND
2014-01-085442-801-0944ND
2014-04-085442-800-1330ND
2014-04-105442-801-08450.550 ppb
2014-05-075442-012-0950ND
2014-07-085442-800-09300.560 ppb
2014-07-085442-801-08250.740 ppb
2014-10-065442-800-10400.560 ppb
2014-10-065442-801-09500.610 ppb
2015-01-145442-801-1012ND
2015-01-145442-800-0915ND
2015-04-095442-801-0908ND
2015-04-095442-800-08310.810 ppb
2015-05-125442-012-1040ND
2015-07-085442-801-08300.720 ppb
2015-07-085442-800-09450.540 ppb
2015-10-065442-801-08200.780 ppb
2015-10-065442-800-0930ND
2016-01-135442-801-09250.580 ppb
2016-01-135442-800-10150.650 ppb
2016-02-295442-012-1039ND
2016-04-115442-801-10300.940 ppb
2016-04-115442-800-11250.840 ppb
2016-07-125442-801-12151.07 ppb
2016-07-125442-800-1305ND
2016-10-135442-801-10500.720 ppb
2016-10-135442-800-1145ND
2017-01-105442-801-11541.13 ppb
2017-01-105442-800-12201.46 ppb
2017-07-109588-801-09501.30 ppb
2017-07-109588-800-0900ND
2017-07-199588-012-1058ND