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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

Penn State Univ.

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.

 

37

Samples

0

Samples exceeding legal limit (MCL)

21

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20121.38 ppb440.760 ppb - 2.71 ppb
20131.16 ppb85ND - 2.92 ppb
20140.719 ppb1610ND - 1.96 ppb
2015ND20ND
20160.178 ppb41ND - 0.710 ppb
20170.217 ppb31ND - 0.650 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
2012-08-152H150541.04 ppb
2012-08-152H150541.000 ppb
2012-08-152H150540.760 ppb
2012-08-152H150542.71 ppb
2013-08-123H12038ND
2013-08-123H12038ND
2013-08-123H120382.47 ppb
2013-08-123H120382.78 ppb
2013-11-133K13069-012.92 ppb
2013-11-133K13069-030.530 ppb
2013-11-133K13069-02ND
2013-11-133K13069-040.600 ppb
2014-02-134B13064-010.530 ppb
2014-02-134B13064-030.540 ppb
2014-02-134B13064-02ND
2014-02-134B13064-04ND
2014-05-154E15061-01ND
2014-05-154E15061-020.740 ppb
2014-05-154E15061-040.750 ppb
2014-05-154E15061-03ND
2014-08-144H14120-011.34 ppb
2014-08-144H14120-021.96 ppb
2014-08-144H14120-041.08 ppb
2014-08-144H14120-031.28 ppb
2014-11-134K13101-04ND
2014-11-134K13101-03ND
2014-11-134K13101-011.92 ppb
2014-11-134K13101-021.36 ppb
2015-02-1212446995ND
2015-08-1313185100ND
2016-02-2513917131ND
2016-08-2514804553ND
2016-09-0214975546ND
2016-11-23152826690.710 ppb
2017-03-13158505450.650 ppb
2017-08-2416629494ND
2017-11-2217077350ND