Menu

EWG's Tap Water Database — 2021 UPDATE

Donate

Chloroform

La Verne WD

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

 

142

Samples

0

Samples exceeding legal limit (MCL)

93

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20141.81 ppb2014ND - 4.90 ppb
20152.21 ppb2618ND - 6.80 ppb
20164.72 ppb2213ND - 15.0 ppb
20179.21 ppb2719ND - 32.0 ppb
20183.48 ppb2213ND - 13.0 ppb
20196.99 ppb2516ND - 20.0 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
2014-02-124790-800-08433.20 ppb
2014-02-124790-801-09244.90 ppb
2014-02-124790-802-11194.40 ppb
2014-02-124790-803-12024.00 ppb
2014-05-144790-800-06391.90 ppb
2014-05-144790-801-07401.60 ppb
2014-05-144790-802-09471.90 ppb
2014-05-144790-803-09181.80 ppb
2014-08-064790-008-1010ND
2014-08-064790-009-10190.550 ppb
2014-08-064790-010-10000.530 ppb
2014-08-064790-016-0750ND
2014-08-064790-032-1123ND
2014-08-064790-039-0830ND
2014-08-064790-800-08052.70 ppb
2014-08-064790-801-09102.90 ppb
2014-08-064790-802-12343.20 ppb
2014-08-064790-803-12592.70 ppb
2014-08-274790-046-1113ND
2014-11-194790-012-1121ND
2015-02-044790-800-09161.60 ppb
2015-02-044790-801-09331.50 ppb
2015-02-044790-802-12401.40 ppb
2015-02-044790-803-12150.830 ppb
2015-05-064790-010-1028ND
2015-05-064790-800-08002.70 ppb
2015-05-064790-801-08332.80 ppb
2015-05-064790-802-09193.20 ppb
2015-05-064790-803-09562.60 ppb
2015-08-054790-008-1041ND
2015-08-054790-009-10470.500 ppb
2015-08-054790-010-1025ND
2015-08-054790-012-0635ND
2015-08-054790-800-07436.20 ppb
2015-08-054790-801-08116.80 ppb
2015-08-054790-802-09106.60 ppb
2015-08-054790-803-09485.80 ppb
2015-08-124790-032-1004ND
2015-08-124790-039-0909ND
2015-08-194790-016-0635ND
2015-08-264790-046-1128ND
2015-11-044790-800-08303.50 ppb
2015-11-044790-801-09253.40 ppb
2015-11-044790-802-11213.40 ppb
2015-11-044790-803-10513.90 ppb
2015-11-104790-009-10250.780 ppb
2016-05-044790-032-1211ND
2016-05-044790-800-081512.0 ppb
2016-05-044790-801-084613.0 ppb
2016-05-044790-802-104715.0 ppb
2016-05-044790-803-11247.00 ppb
2016-08-034790-008-1122ND
2016-08-034790-009-1128ND
2016-08-034790-012-0747ND
2016-08-034790-800-083110.00 ppb
2016-08-034790-801-090810.00 ppb
2016-08-034790-802-100111.0 ppb
2016-08-034790-803-10409.60 ppb
2016-08-104790-010-10351.30 ppb
2016-08-174790-032-1045ND
2016-08-174790-039-1015ND
2016-08-174790-046-1055ND
2016-08-314790-016-1123ND
2016-11-024790-800-08202.90 ppb
2016-11-024790-801-08502.90 ppb
2016-11-024790-802-10153.70 ppb
2016-11-024790-803-10505.50 ppb
2016-11-034790-018-1000ND
2017-02-014790-800-080111.0 ppb
2017-02-014790-801-08347.10 ppb
2017-02-014790-802-09403.40 ppb
2017-02-014790-803-10252.30 ppb
2017-03-224790-018-134513.0 ppb
2017-05-034790-800-082523.0 ppb
2017-05-034790-801-090026.0 ppb
2017-05-034790-802-094532.0 ppb
2017-05-034790-803-101520.0 ppb
2017-08-024790-008-1123ND
2017-08-024790-009-1126ND
2017-08-024790-010-11130.640 ppb
2017-08-024790-018-09280.510 ppb
2017-08-024790-032-1145ND
2017-08-024790-800-083619.0 ppb
2017-08-024790-801-090317.0 ppb
2017-08-024790-802-101322.0 ppb
2017-08-024790-803-104615.0 ppb
2017-08-034790-018-0750ND
2017-08-094790-016-0802ND
2017-08-094790-039-0835ND
2017-08-094790-046-1113ND
2017-08-174790-012-0854ND
2017-11-014790-800-09009.30 ppb
2017-11-014790-801-09579.30 ppb
2017-11-014790-802-10579.00 ppb
2017-11-014790-803-11279.00 ppb
2018-02-074790-800-08491.40 ppb
2018-02-074790-801-09201.80 ppb
2018-02-074790-802-10191.70 ppb
2018-02-074790-803-11046.60 ppb
2018-02-144790-010-0939ND
2018-05-024790-800-08535.80 ppb
2018-05-024790-801-09276.00 ppb
2018-05-024790-802-10415.30 ppb
2018-05-024790-803-11094.70 ppb
2018-08-014790-008-0940ND
2018-08-014790-009-1005ND
2018-08-014790-010-09170.550 ppb
2018-08-014790-012-0742ND
2018-08-014790-032-1038ND
2018-08-014790-800-082511.0 ppb
2018-08-014790-801-09159.60 ppb
2018-08-014790-802-101513.0 ppb
2018-08-014790-803-10559.00 ppb
2018-08-084790-012-0755ND
2018-08-084790-016-1045ND
2018-08-084790-039-0820ND
2018-08-084790-046-0925ND
2019-02-064790-010-0843ND
2019-02-064790-800-08204.10 ppb
2019-02-064790-801-09454.70 ppb
2019-02-064790-802-10453.90 ppb
2019-02-064790-803-1120ND
2019-05-014790-010-0928ND
2019-05-014790-800-084516.0 ppb
2019-05-014790-801-093015.0 ppb
2019-05-014790-802-103514.0 ppb
2019-05-014790-803-111010.00 ppb
2019-08-074790-008-1012ND
2019-08-074790-009-1020ND
2019-08-074790-010-09586.90 ppb
2019-08-074790-012-0810ND
2019-08-074790-039-0929ND
2019-08-074790-046-1031ND
2019-08-074790-800-084519.0 ppb
2019-08-074790-801-093518.0 ppb
2019-08-074790-802-103520.0 ppb
2019-08-074790-803-111516.0 ppb
2019-08-144790-016-1100ND
2019-11-064790-800-08256.40 ppb
2019-11-064790-801-08576.50 ppb
2019-11-064790-802-10108.10 ppb
2019-11-064790-803-10456.10 ppb