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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

Tempe Water Supply Corporation 1

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.

 

29

Samples

0

Samples exceeding legal limit (MCL)

6

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND20ND
2013ND60ND
2014ND40ND
20150.957 ppb73ND - 4.70 ppb
20160.960 ppb52ND - 3.70 ppb
20170.800 ppb51ND - 4.00 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
2012-02-29AB82330ND
2012-02-29AB82328ND
2013-02-26AC11569ND
2013-02-26AC11571ND
2013-06-14AC22213ND
2013-06-14AC22216ND
2013-06-14AC22226ND
2013-06-14AC22227ND
2014-01-15AC38992ND
2014-01-15AC38994ND
2014-01-15AC39002ND
2014-06-23AC57637ND
2015-02-24AC817134.70 ppb
2015-02-24AC816991.000 ppb
2015-02-24AC817091.000 ppb
2015-02-24AC81697ND
2015-06-02AC94111ND
2015-09-10AD06572ND
2015-12-03AD15456ND
2016-02-25AD25795ND
2016-02-25AD257911.10 ppb
2016-02-25AD25783ND
2016-02-25AD257853.70 ppb
2016-06-07AD39608ND
2017-06-01AD86365ND
2017-06-01AD864324.00 ppb
2017-06-01AD86412ND
2017-06-01AD86408ND
2017-06-01AD86426ND