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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Mesa Water District

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

 

281

Samples

0

Samples exceeding legal limit (MCL)

172

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20143.81 ppb4731ND - 15.0 ppb
20151.74 ppb4530ND - 5.30 ppb
20161.41 ppb4427ND - 3.20 ppb
20172.16 ppb5029ND - 6.80 ppb
20181.58 ppb4928ND - 3.80 ppb
20191.97 ppb4627ND - 6.20 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
2014-02-119590-801-07553.40 ppb
2014-02-119590-802-08103.70 ppb
2014-02-119590-803-08253.60 ppb
2014-02-119590-804-09502.60 ppb
2014-02-119590-805-1020ND
2014-02-119590-806-11401.70 ppb
2014-02-119590-807-11501.90 ppb
2014-02-119590-808-12051.80 ppb
2014-02-244417-006-0810ND
2014-02-244417-007-1045ND
2014-02-244417-008-1025ND
2014-05-054417-006-0750ND
2014-05-054417-007-0915ND
2014-05-054417-008-0830ND
2014-05-054417-010-0945ND
2014-05-054417-012-0900ND
2014-05-054417-014-0930ND
2014-05-139590-801-08156.70 ppb
2014-05-139590-802-08306.60 ppb
2014-05-139590-803-08456.70 ppb
2014-05-139590-804-09401.10 ppb
2014-05-139590-805-10106.70 ppb
2014-05-139590-806-11156.70 ppb
2014-05-139590-807-11256.70 ppb
2014-05-139590-808-11406.90 ppb
2014-08-044417-006-0805ND
2014-08-044417-007-0930ND
2014-08-044417-008-0825ND
2014-08-149590-801-095515.0 ppb
2014-08-149590-802-10108.70 ppb
2014-08-149590-803-10255.10 ppb
2014-08-149590-804-11402.30 ppb
2014-08-149590-805-121014.0 ppb
2014-08-149590-806-132511.0 ppb
2014-08-149590-807-133511.0 ppb
2014-08-149590-808-135512.0 ppb
2014-11-034417-007-1020ND
2014-11-034417-008-1005ND
2014-11-129590-801-08253.70 ppb
2014-11-129590-802-08353.80 ppb
2014-11-129590-803-08504.00 ppb
2014-11-129590-804-10003.10 ppb
2014-11-129590-805-10351.60 ppb
2014-11-129590-806-11556.00 ppb
2014-11-129590-807-12056.00 ppb
2014-11-129590-808-12204.80 ppb
2014-11-244417-006-0740ND
2015-02-094417-007-0830ND
2015-02-094417-008-0745ND
2015-02-109590-801-09152.70 ppb
2015-02-109590-802-09353.50 ppb
2015-02-109590-803-09553.30 ppb
2015-02-109590-804-10402.50 ppb
2015-02-109590-805-1100ND
2015-02-109590-806-11101.50 ppb
2015-02-109590-807-11201.80 ppb
2015-02-109590-808-11301.60 ppb
2015-03-244417-006-0830ND
2015-05-114417-006-1030ND
2015-05-114417-007-0850ND
2015-05-114417-008-1010ND
2015-05-114417-010-0820ND
2015-05-114417-012-0930ND
2015-05-129590-801-08302.70 ppb
2015-05-129590-802-08452.80 ppb
2015-05-129590-803-09002.60 ppb
2015-05-129590-804-1015ND
2015-05-129590-805-10455.30 ppb
2015-05-129590-806-11552.40 ppb
2015-05-129590-807-12102.80 ppb
2015-05-129590-808-12252.80 ppb
2015-06-084417-014-0925ND
2015-08-104417-006-0835ND
2015-08-104417-010-1010ND
2015-08-104417-014-0950ND
2015-08-119590-801-08202.40 ppb
2015-08-119590-802-08352.70 ppb
2015-08-119590-803-08502.50 ppb
2015-08-119590-804-08554.70 ppb
2015-08-119590-805-10453.80 ppb
2015-08-119590-806-11102.20 ppb
2015-08-119590-807-11202.00 ppb
2015-08-119590-808-11302.10 ppb
2015-11-024417-006-0750ND
2015-11-109590-801-09051.80 ppb
2015-11-109590-802-08553.00 ppb
2015-11-109590-803-08403.30 ppb
2015-11-109590-804-09201.80 ppb
2015-11-109590-805-09401.40 ppb
2015-11-109590-806-08202.10 ppb
2015-11-109590-807-08101.40 ppb
2015-11-109590-808-07553.00 ppb
2016-02-014417-006-0940ND
2016-02-099590-801-09351.60 ppb
2016-02-099590-802-0920ND
2016-02-099590-803-09052.90 ppb
2016-02-099590-804-0950ND
2016-02-099590-805-0845ND
2016-02-099590-806-08051.60 ppb
2016-02-099590-807-08201.70 ppb
2016-02-099590-808-07501.60 ppb
2016-05-094417-006-0950ND
2016-05-094417-007-1035ND
2016-05-094417-008-0930ND
2016-05-094417-010-1100ND
2016-05-094417-012-1015ND
2016-05-109590-801-08102.10 ppb
2016-05-109590-802-08252.80 ppb
2016-05-109590-803-07552.40 ppb
2016-05-109590-804-07403.20 ppb
2016-05-109590-805-0845ND
2016-05-109590-806-09052.00 ppb
2016-05-109590-807-09152.00 ppb
2016-05-109590-808-09302.40 ppb
2016-05-114417-014-0820ND
2016-06-164417-006-0940ND
2016-08-084417-006-1020ND
2016-08-084417-014-1130ND
2016-08-099590-801-09402.00 ppb
2016-08-099590-802-09302.80 ppb
2016-08-099590-803-09152.60 ppb
2016-08-099590-804-09052.10 ppb
2016-08-099590-805-0845ND
2016-08-099590-806-08302.00 ppb
2016-08-099590-807-08152.00 ppb
2016-08-099590-808-08001.80 ppb
2016-09-204417-006-0915ND
2016-10-034417-006-0710ND
2016-11-089590-801-07302.80 ppb
2016-11-089590-802-07452.90 ppb
2016-11-089590-803-07552.70 ppb
2016-11-089590-804-08052.60 ppb
2016-11-089590-805-08201.60 ppb
2016-11-089590-806-08352.50 ppb
2016-11-089590-807-08452.50 ppb
2016-11-089590-808-08552.70 ppb
2017-02-094417-014-0745ND
2017-02-149590-801-10453.00 ppb
2017-02-149590-802-10302.90 ppb
2017-02-149590-803-10052.70 ppb
2017-02-149590-804-10152.40 ppb
2017-02-149590-805-0910ND
2017-02-149590-806-09301.20 ppb
2017-02-149590-807-09451.000 ppb
2017-02-149590-808-0955ND
2017-02-214417-040-0850ND
2017-03-154417-010-0815ND
2017-05-084417-008-0810ND
2017-05-084417-010-1015ND
2017-05-084417-012-0850ND
2017-05-084417-040-0930ND
2017-05-089590-801-08452.90 ppb
2017-05-089590-802-10302.70 ppb
2017-05-089590-803-10152.90 ppb
2017-05-089590-804-10002.90 ppb
2017-05-089590-805-1100ND
2017-05-089590-806-11151.90 ppb
2017-05-089590-807-10452.60 ppb
2017-05-089590-808-11001.50 ppb
2017-06-204417-006-0810ND
2017-07-124417-006-1100ND
2017-07-124417-006-1235ND
2017-08-089590-801-08304.80 ppb
2017-08-089590-802-08353.60 ppb
2017-08-089590-803-08455.00 ppb
2017-08-089590-804-09254.80 ppb
2017-08-089590-805-10406.10 ppb
2017-08-089590-806-11006.80 ppb
2017-08-089590-807-11156.20 ppb
2017-08-089590-808-11255.10 ppb
2017-08-104417-006-0800ND
2017-08-104417-006-0815ND
2017-08-244417-040-0835ND
2017-10-024417-040-0810ND
2017-10-124417-007-0810ND
2017-10-304417-006-0740ND
2017-11-149590-801-10304.60 ppb
2017-11-149590-802-10154.60 ppb
2017-11-149590-803-09454.70 ppb
2017-11-149590-804-10002.80 ppb
2017-11-149590-805-09304.60 ppb
2017-11-149590-806-08454.70 ppb
2017-11-149590-807-08304.60 ppb
2017-11-149590-808-08154.60 ppb
2017-12-214417-007-0810ND
2017-12-214417-007-0820ND
2018-02-139590-806-09202.80 ppb
2018-02-139590-807-09302.30 ppb
2018-02-139590-808-09452.80 ppb
2018-03-074417-006-0925ND
2018-03-074417-007-1035ND
2018-03-079590-801-0945ND
2018-03-079590-802-09352.50 ppb
2018-03-079590-803-09252.50 ppb
2018-03-079590-804-09152.20 ppb
2018-03-079590-805-09001.10 ppb
2018-04-174417-006-0810ND
2018-04-174417-006-0820ND
2018-04-174417-007-0930ND
2018-04-174417-012-0910ND
2018-05-089590-801-11053.20 ppb
2018-05-089590-802-10503.00 ppb
2018-05-089590-803-10402.90 ppb
2018-05-089590-804-10302.30 ppb
2018-05-089590-805-08203.50 ppb
2018-05-089590-806-08053.60 ppb
2018-05-089590-807-07553.80 ppb
2018-05-089590-808-07402.70 ppb
2018-05-234417-014-0750ND
2018-05-314417-010-1430ND
2018-06-054417-006-0820ND
2018-07-094417-006-0820ND
2018-08-084417-007-0940ND
2018-08-084417-008-0840ND
2018-08-084417-040-0815ND
2018-08-149588-801-08002.80 ppb
2018-08-149588-802-08102.90 ppb
2018-08-149588-803-08202.60 ppb
2018-08-149588-804-08302.70 ppb
2018-08-149588-805-08402.50 ppb
2018-08-149588-806-08501.70 ppb
2018-08-149588-807-0900ND
2018-08-149588-808-0910ND
2018-10-224417-006-0815ND
2018-10-224417-007-0905ND
2018-11-149588-801-08103.00 ppb
2018-11-149588-802-08253.30 ppb
2018-11-149588-803-08452.20 ppb
2018-11-149588-804-0905ND
2018-11-149588-805-09203.30 ppb
2018-11-149588-806-09353.30 ppb
2018-11-149588-807-09453.00 ppb
2018-11-149588-808-10003.10 ppb
2018-12-174417-006-0725ND
2018-12-174417-007-0740ND
2019-02-114417-006-0825ND
2019-02-114417-007-0925ND
2019-02-129588-801-09454.30 ppb
2019-02-129588-802-10006.20 ppb
2019-02-129588-803-10106.20 ppb
2019-02-129588-804-10201.20 ppb
2019-02-129588-805-10302.90 ppb
2019-02-129588-806-1045ND
2019-02-129588-807-10551.50 ppb
2019-02-129588-808-11101.10 ppb
2019-02-264417-012-0950ND
2019-05-079588-801-08303.30 ppb
2019-05-079588-802-08453.60 ppb
2019-05-079588-803-08553.40 ppb
2019-05-079588-804-09103.30 ppb
2019-05-079588-805-0920ND
2019-05-079588-806-09303.90 ppb
2019-05-079588-807-09404.30 ppb
2019-05-079588-808-09503.50 ppb
2019-05-134417-040-0840ND
2019-05-204417-006-0820ND
2019-05-204417-007-0925ND
2019-05-204417-008-0850ND
2019-05-204417-010-0955ND
2019-05-294417-014-0810ND
2019-07-094417-006-0950ND
2019-07-294417-007-0930ND
2019-08-139588-801-08303.50 ppb
2019-08-139588-802-08453.50 ppb
2019-08-139588-803-09003.30 ppb
2019-08-139588-804-09152.90 ppb
2019-08-139588-805-10452.60 ppb
2019-08-139588-806-1115ND
2019-08-139588-807-1125ND
2019-08-139588-808-1145ND
2019-09-054417-014-0810ND
2019-10-244417-006-0845ND
2019-10-294417-007-1025ND
2019-11-139588-801-09053.90 ppb
2019-11-139588-802-09153.90 ppb
2019-11-139588-803-09253.90 ppb
2019-11-139588-804-09354.00 ppb
2019-11-139588-805-09052.90 ppb
2019-11-139588-806-09402.50 ppb
2019-11-139588-807-09502.50 ppb
2019-11-139588-808-10102.50 ppb