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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Whitewater Waterworks

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

 

118

Samples

0

Samples exceeding legal limit (MCL)

37

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.550 ppb208ND - 3.10 ppb
20150.566 ppb2211ND - 1.90 ppb
20160.332 ppb217ND - 1.70 ppb
20170.297 ppb196ND - 2.30 ppb
20180.488 ppb184ND - 3.50 ppb
20190.315 ppb185ND - 2.70 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
2014-03-04773349ND
2014-03-04773351ND
2014-03-04773353ND
2014-03-207761100.840 ppb
2014-04-16781216ND
2014-04-16781217ND
2014-04-167812180.850 ppb
2014-04-167812191.60 ppb
2014-07-15803184ND
2014-07-15803181ND
2014-07-158031821.000 ppb
2014-07-318074610.270 ppb
2014-07-318074590.530 ppb
2014-09-168192372.80 ppb
2014-09-168192383.10 ppb
2014-10-16826129ND
2014-10-16826128ND
2014-10-16826126ND
2014-10-16826125ND
2014-10-16826124ND
2015-02-18844244ND
2015-02-18844246ND
2015-02-18844250ND
2015-02-18844254ND
2015-02-188442521.60 ppb
2015-06-01863167ND
2015-06-01863173ND
2015-06-018631710.620 ppb
2015-06-018631700.850 ppb
2015-06-018631691.90 ppb
2015-08-25878840ND
2015-08-25878845ND
2015-08-258788430.700 ppb
2015-08-258788460.800 ppb
2015-08-258788410.870 ppb
2015-08-258788391.20 ppb
2015-08-258788471.60 ppb
2015-12-14897967ND
2015-12-14897968ND
2015-12-14897971ND
2015-12-148979700.910 ppb
2015-12-148979731.40 ppb
2016-01-19902193ND
2016-01-19902194ND
2016-01-19902195ND
2016-01-19902196ND
2016-01-199021971.70 ppb
2016-04-19916905ND
2016-04-199169040.790 ppb
2016-04-199169070.810 ppb
2016-05-27923840ND
2016-07-13933278ND
2016-07-13933279ND
2016-07-13933281ND
2016-07-13933283ND
2016-07-139332850.700 ppb
2016-07-139332840.780 ppb
2016-08-10938568ND
2016-10-11952769ND
2016-10-11952770ND
2016-10-11952773ND
2016-10-119527741.10 ppb
2016-10-119527721.10 ppb
2017-03-06976492ND
2017-03-06976496ND
2017-03-06976498ND
2017-03-06976507ND
2017-03-06976503ND
2017-06-06995762ND
2017-06-06995761ND
2017-06-06995759ND
2017-06-069957580.320 ppb
2017-07-241006693ND
2017-07-241006696ND
2017-07-241006697ND
2017-07-2410066990.680 ppb
2017-07-2410066941.40 ppb
2017-07-2710073142.30 ppb
2017-11-281031083ND
2017-11-281031084ND
2017-11-2810310880.380 ppb
2017-11-2810310860.570 ppb
2018-01-301039117ND
2018-01-301039121ND
2018-01-301039123ND
2018-01-3010391250.790 ppb
2018-04-231051374ND
2018-04-231051377ND
2018-04-231051378ND
2018-04-2310513753.40 ppb
2018-08-071072173ND
2018-08-071072174ND
2018-08-071072176ND
2018-08-071072177ND
2018-08-0710721721.10 ppb
2018-08-0710721713.50 ppb
2018-10-221088316ND
2018-10-221088317ND
2018-10-221088319ND
2018-10-221088320ND
2019-02-251106616ND
2019-02-251106612ND
2019-02-251106608ND
2019-02-2511066141.000 ppb
2019-04-231117103ND
2019-04-231117100ND
2019-04-231117102ND
2019-04-231117099ND
2019-08-261143692ND
2019-08-261143695ND
2019-08-261143696ND
2019-08-2611436980.320 ppb
2019-08-2611436970.450 ppb
2019-08-2611436931.20 ppb
2019-10-291158067ND
2019-10-291158070ND
2019-10-291158071ND
2019-10-2911580682.70 ppb