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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Los Angeles County WW District 40 Reg 38 Lake Los Angeles

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

 

68

Samples

0

Samples exceeding legal limit (MCL)

31

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.347 ppb187ND - 1.30 ppb
20151.48 ppb188ND - 7.70 ppb
20162.85 ppb1812ND - 12.8 ppb
20170.445 ppb124ND - 1.80 ppb
2018N/A00N/A
2019ND20ND

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
2014-01-095442-801-1015ND
2014-01-095442-802-1050ND
2014-01-095442-803-1030ND
2014-01-095442-800-09550.620 ppb
2014-04-075442-803-1140ND
2014-04-075442-800-1115ND
2014-04-075442-801-1125ND
2014-04-075442-802-1150ND
2014-06-175442-003-1117ND
2014-06-175442-008-1108ND
2014-07-095442-803-0930ND
2014-07-095442-801-09150.920 ppb
2014-07-095442-802-10100.800 ppb
2014-07-105442-800-11451.30 ppb
2014-10-085442-801-0934ND
2014-10-085442-800-10390.960 ppb
2014-10-085442-802-10021.10 ppb
2014-10-085442-803-09420.540 ppb
2015-01-145442-801-1045ND
2015-01-145442-802-1115ND
2015-01-145442-800-1035ND
2015-01-145442-803-1100ND
2015-04-085442-801-0925ND
2015-04-085442-802-0945ND
2015-04-085442-800-0955ND
2015-04-085442-803-0935ND
2015-06-225442-003-0915ND
2015-06-225442-008-0915ND
2015-07-085442-802-10422.12 ppb
2015-07-085442-803-10272.06 ppb
2015-07-085442-801-10162.90 ppb
2015-07-085442-800-11063.97 ppb
2015-10-075442-803-12001.71 ppb
2015-10-075442-801-11304.42 ppb
2015-10-075442-802-12151.82 ppb
2015-10-075442-800-11457.70 ppb
2016-01-115442-801-1215ND
2016-01-115442-802-12450.550 ppb
2016-01-115442-803-1225ND
2016-01-115442-800-12320.520 ppb
2016-04-145442-803-090612.5 ppb
2016-04-145442-802-09144.57 ppb
2016-04-145442-801-085512.3 ppb
2016-04-145442-800-083212.8 ppb
2016-05-125442-003-1055ND
2016-05-125442-008-0950ND
2016-07-145442-800-12200.890 ppb
2016-07-145442-802-11303.69 ppb
2016-07-145442-803-1155ND
2016-07-145442-801-12050.830 ppb
2016-10-135442-803-1133ND
2016-10-135442-800-11450.580 ppb
2016-10-135442-802-12210.570 ppb
2016-10-135442-801-11591.58 ppb
2017-01-095442-803-1409ND
2017-01-095442-800-14220.540 ppb
2017-01-095442-802-1450ND
2017-01-095442-801-1457ND
2017-04-209590-801-10551.40 ppb
2017-04-209590-800-10301.60 ppb
2017-04-209590-802-11281.80 ppb
2017-04-209590-803-1112ND
2017-07-179588-800-1047ND
2017-07-179588-801-0943ND
2017-07-179588-802-1123ND
2017-07-179588-803-0953ND
2019-01-089590-008-1019ND
2019-05-079590-003-1047ND