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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Chatsworth

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

 

113

Samples

0

Samples exceeding legal limit (MCL)

78

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20145.40 ppb1811ND - 18.0 ppb
20155.49 ppb1812ND - 13.0 ppb
20166.75 ppb1914ND - 23.0 ppb
20176.64 ppb1812ND - 22.0 ppb
20185.78 ppb1813ND - 15.0 ppb
20194.45 ppb2216ND - 18.0 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
2014-03-05AI29332ND
2014-03-05AI293332.50 ppb
2014-03-05AI2933411.0 ppb
2014-03-05AI293354.60 ppb
2014-04-28AI38853ND
2014-04-28AI388546.30 ppb
2014-06-03AI42069ND
2014-06-03AI42070ND
2014-06-03AI420716.60 ppb
2014-06-03AI420728.20 ppb
2014-09-03AI52318ND
2014-09-03AI5231911.0 ppb
2014-09-03AI5232016.0 ppb
2014-09-03AI5232118.0 ppb
2014-12-02AI60412ND
2014-12-02AI604135.70 ppb
2014-12-02AI604147.30 ppb
2014-12-02AI60415ND
2015-03-02AI65736ND
2015-03-02AI657377.30 ppb
2015-03-02AI657389.20 ppb
2015-03-02AI657395.70 ppb
2015-03-16AI69025ND
2015-03-16AI6902610.00 ppb
2015-06-01AI78387ND
2015-06-01AI783883.90 ppb
2015-06-01AI7838913.0 ppb
2015-06-01AI783909.30 ppb
2015-09-01AI88404ND
2015-09-01AI884055.20 ppb
2015-09-01AI884067.90 ppb
2015-09-01AI8840710.00 ppb
2015-12-01AJ01787ND
2015-12-01AJ017888.30 ppb
2015-12-01AJ017899.00 ppb
2015-12-01AJ01790ND
2016-03-01AJ07229ND
2016-03-01AJ072307.20 ppb
2016-03-01AJ072317.80 ppb
2016-03-01AJ07232ND
2016-03-21AJ08416ND
2016-03-21AJ084171.20 ppb
2016-03-21AJ0841812.0 ppb
2016-06-01AJ131985.50 ppb
2016-06-01AJ131998.10 ppb
2016-06-01AJ132008.70 ppb
2016-06-01AJ1320112.0 ppb
2016-09-07AJ25987ND
2016-09-07AJ259887.00 ppb
2016-09-07AJ2598911.0 ppb
2016-09-07AJ2599023.0 ppb
2016-12-06AJ360437.70 ppb
2016-12-06AJ360447.20 ppb
2016-12-06AJ36045ND
2016-12-06AJ360469.90 ppb
2017-03-07AJ47649ND
2017-03-07AJ47650ND
2017-03-07AJ4765117.0 ppb
2017-03-07AJ476527.50 ppb
2017-06-06AJ56860ND
2017-06-06AJ568612.30 ppb
2017-06-06AJ5686222.0 ppb
2017-06-06AJ5686314.0 ppb
2017-06-20AJ58059ND
2017-06-20AJ580609.00 ppb
2017-09-06AJ67132ND
2017-09-06AJ671335.70 ppb
2017-09-06AJ671349.60 ppb
2017-09-06AJ671355.40 ppb
2017-12-04AJ74588ND
2017-12-04AJ745893.90 ppb
2017-12-04AJ7459020.0 ppb
2017-12-04AJ745913.20 ppb
2018-03-05AJ84932ND
2018-03-05AJ849337.00 ppb
2018-03-05AJ8493412.0 ppb
2018-03-05AJ849355.20 ppb
2018-05-07AJ88817ND
2018-05-07AJ888186.10 ppb
2018-06-05AJ90745ND
2018-06-05AJ907463.40 ppb
2018-06-05AJ9074712.0 ppb
2018-06-05AJ907488.70 ppb
2018-09-06AK00027ND
2018-09-06AK000282.00 ppb
2018-09-06AK0002915.0 ppb
2018-09-06AK0003012.0 ppb
2018-11-27AK06768ND
2018-11-27AK067695.40 ppb
2018-11-27AK067709.70 ppb
2018-11-27AK067715.50 ppb
2019-02-26AK12102ND
2019-02-26AK121036.10 ppb
2019-02-26AK121045.00 ppb
2019-02-26AK121052.90 ppb
2019-04-29AK15998ND
2019-04-29AK159991.70 ppb
2019-04-29AK160004.70 ppb
2019-05-14AK17445ND
2019-05-14AK174466.70 ppb
2019-05-14AK1744711.0 ppb
2019-05-14AK174488.00 ppb
2019-05-20AK178381.70 ppb
2019-07-16AK225001.10 ppb
2019-09-03AK29085ND
2019-09-03AK290863.80 ppb
2019-09-03AK2908718.0 ppb
2019-09-03AK2908811.0 ppb
2019-10-14AK35010ND
2019-12-03AK37510ND
2019-12-03AK375114.40 ppb
2019-12-03AK375127.80 ppb
2019-12-03AK375134.10 ppb