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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Cal/Am Water Company - San Marino

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

 

510

Samples

0

Samples exceeding legal limit (MCL)

111

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.248 ppb1038ND - 10.00 ppb
20150.430 ppb1029ND - 11.0 ppb
20160.382 ppb906ND - 13.0 ppb
20170.333 ppb7914ND - 6.40 ppb
20180.599 ppb7231ND - 3.80 ppb
20190.995 ppb6443ND - 8.30 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
2014-01-061225-010-1025ND
2014-01-061225-014-1005ND
2014-01-061225-014-1010ND
2014-01-061225-044-0900ND
2014-01-131225-044-1045ND
2014-01-211225-044-1315ND
2014-01-271225-007-1225ND
2014-01-271225-044-1320ND
2014-02-031225-007-0830ND
2014-02-031225-044-1040ND
2014-02-111225-044-1100ND
2014-02-181225-044-1000ND
2014-02-219588-800-09052.10 ppb
2014-02-219588-801-0920ND
2014-02-219588-802-08351.40 ppb
2014-02-219588-803-08501.40 ppb
2014-03-109588-007-0950ND
2014-03-241225-044-1100ND
2014-04-021225-007-0840ND
2014-04-021225-044-1215ND
2014-04-071225-044-0945ND
2014-04-141225-006-1050ND
2014-04-141225-007-1110ND
2014-04-141225-011-0855ND
2014-04-141225-020-1045ND
2014-04-141225-023-0935ND
2014-04-141225-029-0950ND
2014-04-141225-032-1015ND
2014-04-141225-044-0910ND
2014-04-141225-044-0925ND
2014-04-211225-044-0940ND
2014-04-281225-044-0940ND
2014-05-051225-007-0910ND
2014-05-051225-014-1000ND
2014-05-051225-014-1300ND
2014-05-051225-044-1050ND
2014-05-121225-014-1300ND
2014-05-121225-044-1045ND
2014-05-131225-014-1420ND
2014-05-131225-014-1425ND
2014-05-141225-010-1200ND
2014-05-141225-010-1430ND
2014-05-191225-010-0850ND
2014-05-191225-044-1315ND
2014-05-271225-044-1045ND
2014-06-021225-007-1045ND
2014-06-021225-010-0830ND
2014-06-029588-032-1010ND
2014-06-021225-044-0925ND
2014-06-091225-044-1000ND
2014-06-161225-044-1230ND
2014-06-231225-017-1045ND
2014-06-231225-044-0940ND
2014-07-011225-044-10153.60 ppb
2014-07-071225-044-1210ND
2014-07-141225-007-1330ND
2014-07-141225-010-1015ND
2014-07-141225-044-1140ND
2014-07-219590-044-0930ND
2014-07-281225-044-1035ND
2014-08-041225-007-0940ND
2014-08-041225-010-0920ND
2014-08-041225-044-1100ND
2014-08-111225-044-1015ND
2014-08-181225-044-1120ND
2014-08-229588-800-09103.30 ppb
2014-08-229588-801-09251.90 ppb
2014-08-229588-802-084010.00 ppb
2014-08-229588-803-08551.80 ppb
2014-08-251225-044-1000ND
2014-09-021225-007-0945ND
2014-09-021225-010-1220ND
2014-09-021225-044-1145ND
2014-09-039588-010-0900ND
2014-09-039588-011-0945ND
2014-09-039588-017-0915ND
2014-09-039588-020-1000ND
2014-09-039588-023-1020ND
2014-09-081225-044-1115ND
2014-09-161225-044-0945ND
2014-09-221225-044-0955ND
2014-09-291225-044-1250ND
2014-10-061225-007-0915ND
2014-10-061225-010-0830ND
2014-10-061225-044-1130ND
2014-10-131225-044-0940ND
2014-10-201225-044-1135ND
2014-10-271225-044-1130ND
2014-11-031225-007-0915ND
2014-11-031225-010-0845ND
2014-11-031225-044-1030ND
2014-11-101225-044-1030ND
2014-11-171225-044-1130ND
2014-11-219588-800-0845ND
2014-11-219588-801-0900ND
2014-11-219588-802-0815ND
2014-11-219588-803-0830ND
2014-11-241225-044-1000ND
2014-12-011225-007-0930ND
2014-12-011225-010-1225ND
2014-12-011225-044-1045ND
2014-12-081225-044-1245ND
2014-12-151225-044-1000ND
2015-01-051225-007-0935ND
2015-01-051225-010-0855ND
2015-01-051225-044-1130ND
2015-01-121225-044-0940ND
2015-01-201225-044-1030ND
2015-01-261225-044-1030ND
2015-02-021225-007-0930ND
2015-02-021225-010-0900ND
2015-02-021225-044-1100ND
2015-02-091225-044-1110ND
2015-02-171225-044-1215ND
2015-02-231225-044-0830ND
2015-02-259588-800-1520ND
2015-02-259588-801-1540ND
2015-02-259588-802-14352.00 ppb
2015-02-259588-803-14552.10 ppb
2015-03-021225-010-0850ND
2015-03-021225-044-1045ND
2015-03-091225-044-1030ND
2015-03-171225-044-1300ND
2015-03-209588-007-0715ND
2015-03-209590-007-0920ND
2015-03-231225-044-1100ND
2015-04-011225-044-1030ND
2015-04-061225-007-0845ND
2015-04-061225-010-0820ND
2015-04-061225-044-1015ND
2015-04-131225-044-1045ND
2015-04-201225-044-0935ND
2015-04-271225-044-0930ND
2015-05-041225-007-0915ND
2015-05-041225-010-0840ND
2015-05-041225-044-1010ND
2015-05-111225-044-1000ND
2015-05-121225-007-1200ND
2015-05-121225-017-1245ND
2015-05-181225-011-1050ND
2015-05-181225-023-1110ND
2015-05-181225-032-1130ND
2015-05-181225-044-1055ND
2015-05-181225-044-1110ND
2015-05-201225-006-1255ND
2015-05-201225-029-12352.20 ppb
2015-05-261225-044-1010ND
2015-05-269588-800-1045ND
2015-05-269588-801-1105ND
2015-05-269588-802-1015ND
2015-05-269588-803-1030ND
2015-05-271225-010-0830ND
2015-05-271225-020-0855ND
2015-06-011225-007-0850ND
2015-06-011225-010-0830ND
2015-06-011225-044-1045ND
2015-06-049588-032-1000ND
2015-06-081225-044-1015ND
2015-06-151225-044-1045ND
2015-06-221225-044-1000ND
2015-06-291225-044-1110ND
2015-07-061225-007-0920ND
2015-07-061225-010-0845ND
2015-07-061225-044-1100ND
2015-07-131225-044-0845ND
2015-07-201225-044-1100ND
2015-07-271225-044-0920ND
2015-08-051225-007-1040ND
2015-08-051225-010-0815ND
2015-08-051225-044-0915ND
2015-08-101225-044-0940ND
2015-08-181225-044-1000ND
2015-08-241225-044-0845ND
2015-08-249588-800-085511.0 ppb
2015-08-249588-801-0905ND
2015-08-249588-802-0830ND
2015-08-249588-803-08402.00 ppb
2015-09-011225-007-0915ND
2015-09-011225-010-1050ND
2015-09-011225-044-1000ND
2015-09-089588-010-0915ND
2015-09-089588-011-1020ND
2015-09-089588-017-1035ND
2015-09-089588-020-0935ND
2015-09-089588-023-0950ND
2015-09-081225-044-1000ND
2015-09-151225-044-1015ND
2015-09-211225-044-0915ND
2015-09-281225-044-0945ND
2015-10-051225-007-0840ND
2015-10-051225-010-0805ND
2015-10-051225-044-0945ND
2015-10-121225-044-0945ND
2015-10-191225-044-0945ND
2015-10-261225-044-0945ND
2015-11-051225-044-0945ND
2015-11-091225-044-0845ND
2015-11-171225-044-0930ND
2015-11-231225-044-0920ND
2015-11-239588-800-08455.60 ppb
2015-11-239588-801-09004.80 ppb
2015-11-239588-802-08157.30 ppb
2015-11-239588-803-08306.90 ppb
2015-12-011225-044-0845ND
2015-12-141225-044-0930ND
2016-01-121225-007-0830ND
2016-02-091225-007-0845ND
2016-02-229588-800-0930ND
2016-02-229588-801-0920ND
2016-02-229588-802-1000ND
2016-02-229588-803-0945ND
2016-03-011225-007-0900ND
2016-03-029588-007-0915ND
2016-04-111225-007-0845ND
2016-04-131225-044-1110ND
2016-04-191225-044-0930ND
2016-04-251225-044-1015ND
2016-05-021225-007-1115ND
2016-05-021225-044-0915ND
2016-05-091225-044-0950ND
2016-05-161225-044-0845ND
2016-05-231225-044-0845ND
2016-05-239588-800-0905ND
2016-05-239588-801-0915ND
2016-05-239588-802-0840ND
2016-05-239588-803-08501.20 ppb
2016-06-011225-044-0820ND
2016-06-061225-006-1100ND
2016-06-061225-007-1210ND
2016-06-061225-010-1000ND
2016-06-061225-017-1130ND
2016-06-061225-020-1040ND
2016-06-061225-023-1135ND
2016-06-061225-029-1045ND
2016-06-061225-032-1105ND
2016-06-061225-044-1000ND
2016-06-099588-032-1005ND
2016-06-131225-044-0830ND
2016-06-211225-044-0815ND
2016-06-281225-044-0900ND
2016-07-051225-007-0950ND
2016-07-051225-044-0815ND
2016-07-121225-044-0745ND
2016-07-181225-044-0915ND
2016-07-251225-044-0930ND
2016-08-011225-007-0930ND
2016-08-011225-044-1030ND
2016-08-081225-044-0935ND
2016-08-161225-044-0915ND
2016-08-221225-044-0945ND
2016-08-229588-800-09105.10 ppb
2016-08-229588-801-09252.80 ppb
2016-08-229588-802-084511.0 ppb
2016-08-229588-803-090013.0 ppb
2016-08-301225-044-0945ND
2016-08-309590-044-0945ND
2016-09-061225-007-0845ND
2016-09-061225-044-0950ND
2016-09-079588-010-0945ND
2016-09-079588-011-1105ND
2016-09-079588-017-1020ND
2016-09-079588-020-1130ND
2016-09-079588-023-1120ND
2016-09-121225-044-1000ND
2016-09-191225-044-0950ND
2016-09-271225-044-0940ND
2016-09-279590-044-0940ND
2016-10-031225-007-0815ND
2016-10-031225-044-0945ND
2016-10-039590-044-0945ND
2016-10-101225-044-0945ND
2016-10-109590-044-0945ND
2016-10-171225-044-1015ND
2016-10-179590-044-1015ND
2016-10-241225-044-1010ND
2016-10-249590-044-1010ND
2016-11-011225-007-1220ND
2016-11-011225-044-1150ND
2016-11-019590-044-1150ND
2016-11-071225-044-0850ND
2016-11-079590-044-0850ND
2016-11-141225-044-0830ND
2016-11-149590-044-0830ND
2016-11-211225-044-0930ND
2016-11-219590-044-0930ND
2016-11-281225-044-1110ND
2016-12-051225-007-1125ND
2016-12-051225-044-1025ND
2016-12-121225-044-0940ND
2016-12-191225-044-0945ND
2016-12-271225-044-0900ND
2016-12-309588-800-10101.30 ppb
2016-12-309588-801-1025ND
2016-12-309588-802-0940ND
2016-12-309588-803-0955ND
2017-01-031225-044-0915ND
2017-01-091225-044-0830ND
2017-01-171225-044-0900ND
2017-01-231225-044-0800ND
2017-01-301225-044-0845ND
2017-02-071225-044-0915ND
2017-02-131225-044-0900ND
2017-02-211225-044-0840ND
2017-02-249588-800-10152.60 ppb
2017-02-249588-801-10301.80 ppb
2017-02-249588-802-09502.20 ppb
2017-02-249588-803-10001.40 ppb
2017-02-271225-044-0840ND
2017-03-019588-007-0900ND
2017-03-061225-044-0920ND
2017-03-131225-044-0910ND
2017-03-201225-044-0945ND
2017-03-271225-044-0830ND
2017-04-031225-044-1040ND
2017-04-101225-044-1330ND
2017-04-171225-044-0845ND
2017-04-241225-044-0845ND
2017-05-011225-044-0920ND
2017-05-081225-044-0850ND
2017-05-159590-044-0930ND
2017-05-221225-044-0800ND
2017-05-229588-800-1030ND
2017-05-229588-801-10401.30 ppb
2017-05-229588-802-1005ND
2017-05-229588-803-1020ND
2017-05-301225-044-1030ND
2017-06-051225-044-0915ND
2017-06-089588-032-1045ND
2017-06-121225-017-0805ND
2017-06-121225-044-0945ND
2017-06-191225-029-0835ND
2017-06-191225-044-0915ND
2017-06-261225-006-0820ND
2017-06-261225-044-0910ND
2017-07-051225-044-08352.00 ppb
2017-07-101225-044-0715ND
2017-07-171225-044-1030ND
2017-07-241225-044-0930ND
2017-07-311225-007-1200ND
2017-07-311225-053-1200ND
2017-08-011225-044-0930ND
2017-08-081225-044-0815ND
2017-08-141225-044-0900ND
2017-08-211225-044-0905ND
2017-08-229588-800-08556.40 ppb
2017-08-229588-801-09052.30 ppb
2017-08-229588-802-08301.10 ppb
2017-08-229588-803-08401.000 ppb
2017-08-291225-044-1040ND
2017-09-051225-044-0800ND
2017-09-111225-044-1000ND
2017-09-181225-044-0945ND
2017-09-209588-010-0900ND
2017-09-209588-017-0920ND
2017-09-209588-020-1010ND
2017-09-209588-023-0955ND
2017-09-251225-044-0920ND
2017-10-021225-044-0850ND
2017-10-091225-044-0815ND
2017-10-161225-044-0820ND
2017-10-231225-044-0800ND
2017-10-301225-044-0820ND
2017-11-061225-044-08451.000 ppb
2017-11-131225-044-09001.10 ppb
2017-11-201225-044-0850ND
2017-11-219588-800-0835ND
2017-11-219588-801-0855ND
2017-11-219588-802-0800ND
2017-11-219588-803-0815ND
2017-11-271225-044-0910ND
2017-12-041225-044-0940ND
2017-12-111225-044-1100ND
2017-12-181225-044-08301.10 ppb
2017-12-261225-044-08301.000 ppb
2018-01-021225-044-09201.10 ppb
2018-01-049590-007-1000ND
2018-01-081225-044-0830ND
2018-01-251225-044-0745ND
2018-01-301225-044-0800ND
2018-02-051225-044-0800ND
2018-02-121225-044-0815ND
2018-02-201225-044-0750ND
2018-02-209588-800-1005ND
2018-02-209588-801-1020ND
2018-02-209588-802-0940ND
2018-02-209588-803-0950ND
2018-02-261225-044-0750ND
2018-03-051225-044-1100ND
2018-03-069588-007-0920ND
2018-03-121225-044-1050ND
2018-03-191225-044-1000ND
2018-03-261225-044-0920ND
2018-04-031225-044-0930ND
2018-04-091225-044-0815ND
2018-04-161225-044-0815ND
2018-04-231225-044-0744ND
2018-05-011225-044-0848ND
2018-05-071225-044-0915ND
2018-05-141225-044-0800ND
2018-05-211225-044-0845ND
2018-05-229588-800-08353.20 ppb
2018-05-229588-801-08501.000 ppb
2018-05-229588-802-08103.00 ppb
2018-05-229588-803-08203.80 ppb
2018-05-291225-044-08201.000 ppb
2018-06-041225-006-0745ND
2018-06-041225-029-0800ND
2018-06-041225-044-08301.10 ppb
2018-06-111225-044-11001.10 ppb
2018-06-149588-032-1100ND
2018-06-181225-044-0830ND
2018-06-251225-044-08451.000 ppb
2018-07-021225-044-08501.10 ppb
2018-07-091225-044-08241.10 ppb
2018-07-161225-044-0830ND
2018-07-231225-044-09001.10 ppb
2018-07-301225-044-08301.20 ppb
2018-08-061225-044-08451.10 ppb
2018-08-131225-044-09001.10 ppb
2018-08-201225-044-09301.10 ppb
2018-08-271225-044-10151.10 ppb
2018-08-279588-800-09302.20 ppb
2018-08-279588-801-0915ND
2018-08-279588-802-0955ND
2018-08-279588-803-0940ND
2018-09-041225-044-08451.10 ppb
2018-09-101225-044-08301.10 ppb
2018-09-171225-044-09451.10 ppb
2018-09-209588-017-0950ND
2018-09-209588-020-1040ND
2018-09-209588-023-1020ND
2018-09-241225-044-08451.000 ppb
2018-10-011225-044-09151.30 ppb
2018-10-081225-044-08301.10 ppb
2018-10-151225-044-09201.10 ppb
2018-10-221225-044-0920ND
2018-10-291225-044-10451.20 ppb
2018-11-051225-044-09501.40 ppb
2018-11-131225-044-08451.30 ppb
2018-11-191225-044-0830ND
2018-11-261225-044-0930ND
2018-11-269588-800-11051.90 ppb
2018-11-269588-801-1120ND
2018-11-269588-802-10401.000 ppb
2018-11-269588-803-1055ND
2018-12-031225-044-08081.10 ppb
2019-02-229588-800-1120ND
2019-02-229588-801-11101.50 ppb
2019-02-229588-802-11401.40 ppb
2019-02-229588-803-11301.40 ppb
2019-03-199588-007-1025ND
2019-04-151225-044-1325ND
2019-04-221225-044-11201.10 ppb
2019-04-291225-044-12001.10 ppb
2019-05-061225-044-1220ND
2019-05-139588-017-1015ND
2019-05-139588-020-0930ND
2019-05-139588-023-0945ND
2019-05-139588-032-0955ND
2019-05-131225-044-11451.20 ppb
2019-05-159590-006-1130ND
2019-05-159590-029-0845ND
2019-05-159590-044-0925ND
2019-05-201225-044-1200ND
2019-05-249588-800-11151.80 ppb
2019-05-249588-801-11301.90 ppb
2019-05-249588-802-1045ND
2019-05-249588-803-11001.000 ppb
2019-05-281225-044-13391.10 ppb
2019-06-031225-044-1113ND
2019-06-101225-044-12451.000 ppb
2019-06-171225-044-12101.000 ppb
2019-06-189588-011-10058.30 ppb
2019-06-241225-044-1111ND
2019-07-011225-044-12151.20 ppb
2019-07-081225-044-11021.20 ppb
2019-07-151225-044-11221.000 ppb
2019-07-221225-044-12301.10 ppb
2019-07-291225-044-12001.10 ppb
2019-08-051225-044-11151.20 ppb
2019-08-079588-011-1000ND
2019-08-121225-044-12401.10 ppb
2019-08-191225-044-12021.10 ppb
2019-08-269588-010-0945ND
2019-08-261225-044-1039ND
2019-08-269588-800-1005ND
2019-08-269588-801-10251.60 ppb
2019-08-269588-802-09453.30 ppb
2019-08-269588-803-09552.10 ppb
2019-09-031225-044-1315ND
2019-09-091225-044-11001.10 ppb
2019-09-161225-044-13001.10 ppb
2019-09-231225-044-14151.10 ppb
2019-10-011225-044-13301.20 ppb
2019-10-049590-044-0958ND
2019-10-071225-044-13301.20 ppb
2019-10-141225-044-11151.20 ppb
2019-10-211225-044-11451.20 ppb
2019-10-281225-044-12001.50 ppb
2019-11-041225-044-11301.50 ppb
2019-11-121225-044-11451.50 ppb
2019-11-219588-800-10501.40 ppb
2019-11-219588-801-11101.60 ppb
2019-11-219588-802-10201.50 ppb
2019-11-219588-803-10351.10 ppb
2019-11-251225-044-11201.20 ppb
2019-12-021225-044-12101.20 ppb
2019-12-091225-044-12001.10 ppb
2019-12-161225-044-11301.20 ppb
2019-12-239590-044-08301.000 ppb