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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

California Domestic Water Company

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

 

252

Samples

0

Samples exceeding legal limit (MCL)

8

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.0424 ppb331ND - 1.40 ppb
20150.0667 ppb332ND - 1.10 ppb
20160.117 ppb353ND - 1.60 ppb
2017ND500ND
2018ND390ND
20190.0311 ppb622ND - 1.20 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
2014-01-299588-800-1405ND
2014-01-299588-801-1430ND
2014-01-299588-802-1415ND
2014-03-219588-014-0910ND
2014-04-073761-004-0854ND
2014-04-073761-005-0939ND
2014-04-073761-006-0903ND
2014-04-073761-007-0921ND
2014-04-073761-008-0815ND
2014-04-073761-009-0735ND
2014-04-073761-014-1025ND
2014-04-099588-004-1120ND
2014-04-099588-005-1115ND
2014-04-099588-006-1140ND
2014-04-099588-007-1130ND
2014-04-099588-008-1150ND
2014-04-093761-020-07211.40 ppb
2014-04-289588-800-1315ND
2014-04-289588-801-1340ND
2014-04-289588-802-1325ND
2014-07-299588-800-0730ND
2014-07-299588-801-0755ND
2014-07-299588-802-0740ND
2014-10-063761-004-0855ND
2014-10-063761-005-1024ND
2014-10-063761-006-0943ND
2014-10-063761-007-1000ND
2014-10-063761-008-0837ND
2014-10-063761-009-0750ND
2014-10-299588-800-1245ND
2014-10-299588-801-1315ND
2014-10-299588-802-1255ND
2014-12-153761-014-0945ND
2015-01-079588-014-0905ND
2015-01-279588-800-1130ND
2015-01-279588-801-1155ND
2015-01-279588-802-1140ND
2015-04-063761-004-0850ND
2015-04-063761-005-0555ND
2015-04-063761-006-0743ND
2015-04-063761-007-0757ND
2015-04-063761-008-0730ND
2015-04-063761-009-0525ND
2015-04-063761-014-0700ND
2015-04-149588-004-0855ND
2015-04-149588-006-0945ND
2015-04-149588-007-09551.10 ppb
2015-04-149588-008-0935ND
2015-04-159588-005-0915ND
2015-04-279588-800-1105ND
2015-04-279588-801-1130ND
2015-04-279588-802-1115ND
2015-07-309588-800-1210ND
2015-07-309588-801-1240ND
2015-07-309588-802-1225ND
2015-10-053761-004-0809ND
2015-10-053761-005-0943ND
2015-10-053761-006-0840ND
2015-10-053761-007-0921ND
2015-10-053761-008-0902ND
2015-10-053761-009-0725ND
2015-10-053761-014-1029ND
2015-10-279588-800-1110ND
2015-10-279588-801-1140ND
2015-10-279588-802-1125ND
2015-11-199588-020-10551.10 ppb
2016-01-279588-800-1115ND
2016-01-279588-801-1140ND
2016-01-279588-802-1130ND
2016-04-043761-004-0915ND
2016-04-043761-005-1030ND
2016-04-043761-006-1015ND
2016-04-043761-007-0958ND
2016-04-043761-008-0852ND
2016-04-043761-009-0745ND
2016-04-043761-014-1140ND
2016-04-119588-004-0935ND
2016-04-119588-005-0850ND
2016-04-119588-006-0910ND
2016-04-119588-007-0915ND
2016-04-119588-008-0950ND
2016-04-119588-014-0845ND
2016-04-269588-800-1155ND
2016-04-269588-801-1230ND
2016-04-269588-802-1210ND
2016-07-069588-020-0910ND
2016-07-279588-800-1155ND
2016-07-279588-801-1225ND
2016-07-279588-802-1205ND
2016-10-033761-004-0829ND
2016-10-033761-005-09481.000 ppb
2016-10-033761-006-0903ND
2016-10-033761-007-0924ND
2016-10-033761-008-0813ND
2016-10-033761-009-0729ND
2016-10-033761-014-1107ND
2016-10-033761-020-10041.50 ppb
2016-10-149588-020-09251.60 ppb
2016-10-279588-800-1140ND
2016-10-279588-801-1215ND
2016-10-279588-802-1200ND
2017-01-109588-020-0910ND
2017-01-269588-800-1115ND
2017-01-269588-801-1145ND
2017-01-269588-802-1130ND
2017-04-033761-009-0748ND
2017-04-059588-004-0920ND
2017-04-059588-005-0905ND
2017-04-059588-006-0930ND
2017-04-059588-007-0940ND
2017-04-059588-008-0955ND
2017-04-059588-014-0900ND
2017-04-059588-020-0910ND
2017-04-193761-004-0910ND
2017-04-193761-005-0837ND
2017-04-193761-006-0819ND
2017-04-193761-007-0809ND
2017-04-193761-008-0957ND
2017-04-193761-009-0935ND
2017-04-193761-014-0857ND
2017-04-193761-020-0850ND
2017-04-269588-800-1105ND
2017-04-269588-801-1135ND
2017-04-269588-802-1115ND
2017-07-269588-800-0710ND
2017-07-269588-801-0725ND
2017-07-269588-802-0700ND
2017-09-263761-009-0930ND
2017-10-023761-004-0837ND
2017-10-023761-005-0919ND
2017-10-023761-006-1003ND
2017-10-023761-007-0940ND
2017-10-023761-008-0815ND
2017-10-023761-009-0729ND
2017-10-023761-014-1115ND
2017-10-023761-020-1020ND
2017-10-269588-800-1115ND
2017-10-269588-801-1145ND
2017-10-269588-802-1130ND
2017-12-043761-004-0835ND
2017-12-043761-005-1012ND
2017-12-043761-006-0923ND
2017-12-043761-007-0937ND
2017-12-043761-008-0817ND
2017-12-043761-013-0854ND
2017-12-043761-014-1053ND
2017-12-043761-020-0956ND
2017-12-113761-013-0850ND
2017-12-133761-013-0930ND
2017-12-183761-013-0950ND
2017-12-273761-013-0843ND
2018-01-023761-013-0830ND
2018-01-103761-013-0854ND
2018-01-293761-013-0922ND
2018-01-299588-800-1130ND
2018-01-299588-801-1155ND
2018-01-299588-802-1140ND
2018-04-023761-004-0900ND
2018-04-023761-007-1018ND
2018-04-023761-008-0931ND
2018-04-023761-009-0757ND
2018-04-109588-004-0850ND
2018-04-109588-005-0900ND
2018-04-109588-006-0915ND
2018-04-109588-007-0920ND
2018-04-109588-008-0930ND
2018-04-109588-014-0945ND
2018-04-109588-020-0905ND
2018-04-233761-005-1022ND
2018-04-233761-006-1002ND
2018-04-233761-007-0953ND
2018-04-233761-014-1042ND
2018-04-233761-020-1013ND
2018-04-269588-800-1120ND
2018-04-269588-801-1140ND
2018-04-269588-802-1130ND
2018-07-269588-800-1030ND
2018-07-269588-801-1100ND
2018-07-269588-802-1045ND
2018-10-013761-005-1029ND
2018-10-013761-006-0958ND
2018-10-013761-007-0940ND
2018-10-013761-008-0822ND
2018-10-013761-009-0740ND
2018-10-013761-014-1127ND
2018-10-013761-020-1015ND
2018-10-043761-004-0815ND
2018-10-259588-800-1200ND
2018-10-259588-801-1230ND
2018-10-259588-802-1215ND
2019-01-289588-800-1040ND
2019-01-289588-801-1115ND
2019-01-289588-802-1055ND
2019-04-013761-005-1131ND
2019-04-013761-006-0956ND
2019-04-013761-007-0941ND
2019-04-013761-008-0840ND
2019-04-013761-009-0814ND
2019-04-013761-014-1125ND
2019-04-013761-020-1115ND
2019-04-039588-005-0850ND
2019-04-039588-006-0915ND
2019-04-039588-007-0910ND
2019-04-039588-008-0925ND
2019-04-039588-014-0905ND
2019-04-039588-020-0900ND
2019-04-083761-004-0920ND
2019-04-269588-800-1120ND
2019-04-269588-801-1150ND
2019-04-269588-802-1135ND
2019-06-069588-004-1100ND
2019-07-013761-013-0905ND
2019-07-083761-013-0842ND
2019-07-153761-013-0920ND
2019-07-259588-800-0815ND
2019-07-259588-801-0830ND
2019-07-259588-802-0805ND
2019-07-293761-013-0900ND
2019-08-053761-013-0910ND
2019-08-123761-013-0900ND
2019-08-263761-013-0853ND
2019-09-033761-013-0552ND
2019-09-093761-013-0855ND
2019-09-163761-013-0902ND
2019-09-231233-013-09280.730 ppb
2019-09-303761-013-0625ND
2019-10-073761-004-0919ND
2019-10-073761-006-1118ND
2019-10-073761-007-1130ND
2019-10-073761-008-0843ND
2019-10-073761-009-0800ND
2019-10-073761-013-0933ND
2019-10-073761-014-0958ND
2019-10-143761-013-0915ND
2019-10-213761-013-0928ND
2019-10-253761-005-0717ND
2019-10-253761-020-07261.20 ppb
2019-10-283761-013-0830ND
2019-10-319588-803-0850ND
2019-10-319588-804-0910ND
2019-10-319588-805-0930ND
2019-10-319588-806-0945ND
2019-10-319588-807-1000ND
2019-11-083761-013-1030ND
2019-11-113761-013-0840ND
2019-11-183761-013-0852ND
2019-11-253761-013-0832ND
2019-12-023761-013-0906ND
2019-12-093761-013-0821ND
2019-12-163761-013-0842ND
2019-12-233761-013-0814ND
2019-12-303761-013-0917ND