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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Green Valley SUD

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

 

110

Samples

0

Samples exceeding legal limit (MCL)

35

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20142.24 ppb169ND - 11.9 ppb
20152.29 ppb197ND - 19.0 ppb
20160.720 ppb208ND - 3.60 ppb
20170.706 ppb184ND - 4.10 ppb
20180.779 ppb193ND - 9.30 ppb
20191.78 ppb184ND - 25.1 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
2014-02-19AC4355311.9 ppb
2014-02-19AC435591.000 ppb
2014-02-19AC435871.000 ppb
2014-02-19AC43551ND
2014-04-03AC492067.10 ppb
2014-04-03AC49207ND
2014-04-03AC49204ND
2014-04-03AC492271.000 ppb
2014-07-14AC59615ND
2014-07-14AC59589ND
2014-07-14AC59608ND
2014-09-18AC674875.90 ppb
2014-11-11AC717225.00 ppb
2014-11-11AC717251.60 ppb
2014-11-11AC71728ND
2014-11-11AC717271.40 ppb
2015-01-27AC779025.30 ppb
2015-01-27AC77917ND
2015-01-27AC77881ND
2015-01-27AC77880ND
2015-04-15AC88408ND
2015-04-15AC88396ND
2015-04-15AC883505.20 ppb
2015-04-15AC883511.90 ppb
2015-04-15AC88348ND
2015-04-15AC88352ND
2015-07-22AD00642ND
2015-07-22AD006135.90 ppb
2015-07-22AD006095.10 ppb
2015-07-22AD00567ND
2015-07-22AD00612ND
2015-11-20AD1441219.0 ppb
2015-11-20AD143701.20 ppb
2015-11-20AD14369ND
2015-11-20AD14377ND
2016-01-20AD18974ND
2016-01-20AD188763.30 ppb
2016-01-20AD188861.30 ppb
2016-01-20AD18888ND
2016-01-20AD18895ND
2016-04-06AD32077ND
2016-04-06AD320102.10 ppb
2016-04-06AD320141.10 ppb
2016-04-06AD320431.000 ppb
2016-04-06AD320121.000 ppb
2016-06-07AD39632ND
2016-09-16AD500393.60 ppb
2016-09-16AD50057ND
2016-09-16AD50015ND
2016-09-16AD50012ND
2016-09-16AD50153ND
2016-11-03AD564401.000 ppb
2016-11-03AD56441ND
2016-11-03AD56438ND
2016-11-03AD56439ND
2017-01-30AD67581ND
2017-01-30AD674811.20 ppb
2017-01-30AD67512ND
2017-01-30AD67479ND
2017-01-30AD67513ND
2017-04-20AD80390ND
2017-04-20AD803404.10 ppb
2017-04-20AD80341ND
2017-04-20AD80338ND
2017-04-20AD80344ND
2017-08-16AD933843.60 ppb
2017-08-16AD93375ND
2017-08-16AD93373ND
2017-08-16AD93374ND
2017-12-08AE074043.80 ppb
2017-12-08AE07403ND
2017-12-08AE07402ND
2017-12-08AE07401ND
2018-01-26AE11022ND
2018-01-26AE10952ND
2018-01-26AE10951ND
2018-01-26AE10950ND
2018-01-26AE10953ND
2018-04-18AE23016ND
2018-04-18AE23018ND
2018-04-18AE229882.00 ppb
2018-04-18AE22991ND
2018-04-18AE22992ND
2018-04-18AE22990ND
2018-08-16AE373533.50 ppb
2018-08-16AE37352ND
2018-08-16AE37351ND
2018-08-16AE37354ND
2018-10-03AE425139.30 ppb
2018-10-03AE42527ND
2018-10-03AE42545ND
2018-10-03AE42520ND
2019-02-05AE52955ND
2019-02-05AE52927ND
2019-02-05AE5285325.1 ppb
2019-02-05AE52855ND
2019-02-05AE52870ND
2019-02-05AE52876ND
2019-04-11AE619983.60 ppb
2019-04-11AE62023ND
2019-04-11AE61995ND
2019-04-11AE62005ND
2019-08-01AE767611.000 ppb
2019-08-01AE76762ND
2019-08-01AE76763ND
2019-08-01AE76765ND
2019-10-15AE866152.30 ppb
2019-10-15AE86616ND
2019-10-15AE86614ND
2019-10-15AE86618ND