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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Porter 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

 

127

Samples

0

Samples exceeding legal limit (MCL)

12

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20141.95 ppb174ND - 17.0 ppb
20150.850 ppb264ND - 10.00 ppb
2016ND210ND
20170.0857 ppb211ND - 1.80 ppb
20180.129 ppb212ND - 1.60 ppb
20190.0476 ppb211ND - 1.000 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
2014-03-04AC45469ND
2014-03-04AC45487ND
2014-03-04AC45470ND
2014-03-04AC45465ND
2014-04-02AC49103ND
2014-04-02AC491194.00 ppb
2014-04-02AC49117ND
2014-04-02AC49104ND
2014-07-08AC5906910.9 ppb
2014-07-08AC5907117.0 ppb
2014-07-08AC59072ND
2014-07-08AC59070ND
2014-07-08AC59005ND
2014-10-03AC688851.30 ppb
2014-10-03AC68883ND
2014-10-03AC68922ND
2014-10-03AC68882ND
2015-01-28AC78119ND
2015-01-28AC78115ND
2015-01-28AC78120ND
2015-01-28AC78113ND
2015-04-13AC8800510.00 ppb
2015-04-13AC88001ND
2015-04-13AC87991ND
2015-04-13AC87983ND
2015-04-13AC87995ND
2015-04-13AC87989ND
2015-06-15AC95908ND
2015-06-15AC958986.40 ppb
2015-06-15AC95904ND
2015-06-15AC95925ND
2015-07-10AC99133ND
2015-07-10AC99119ND
2015-07-10AC99130ND
2015-07-10AC99131ND
2015-09-30AD09106ND
2015-09-30AD091084.40 ppb
2015-11-19AD14206ND
2015-11-19AD14202ND
2015-11-19AD14197ND
2015-11-19AD14196ND
2015-11-19AD142381.30 ppb
2015-11-19AD14236ND
2016-01-12AD17610ND
2016-01-12AD17602ND
2016-01-12AD17608ND
2016-01-12AD17620ND
2016-01-12AD17618ND
2016-01-12AD17541ND
2016-01-12AD17539ND
2016-01-12AD17547ND
2016-01-12AD17536ND
2016-04-14AD33167ND
2016-04-14AD33166ND
2016-04-14AD33165ND
2016-04-14AD33168ND
2016-07-15AD44472ND
2016-07-15AD44461ND
2016-07-15AD44458ND
2016-07-15AD44453ND
2016-11-01AD55803ND
2016-11-01AD55807ND
2016-11-01AD55804ND
2016-11-01AD55808ND
2017-01-19AD65769ND
2017-01-19AD65767ND
2017-01-19AD657511.80 ppb
2017-01-19AD65761ND
2017-01-19AD65701ND
2017-01-19AD65698ND
2017-01-19AD65699ND
2017-01-19AD65700ND
2017-04-27AD81494ND
2017-04-27AD81492ND
2017-04-27AD81485ND
2017-04-27AD81493ND
2017-08-14AD92893ND
2017-08-14AD92894ND
2017-08-14AD92888ND
2017-08-14AD92892ND
2017-10-11AE00408ND
2017-10-11AE00358ND
2017-10-11AE00355ND
2017-10-11AE00357ND
2017-10-11AE00356ND
2018-01-09AE084091.60 ppb
2018-01-09AE08369ND
2018-01-09AE08367ND
2018-01-09AE08391ND
2018-01-09AE08327ND
2018-01-09AE08329ND
2018-01-09AE08315ND
2018-01-09AE08311ND
2018-04-05AE21432ND
2018-04-05AE21431ND
2018-04-05AE21406ND
2018-04-05AE21405ND
2018-08-31AE39139ND
2018-08-31AE39136ND
2018-08-31AE391401.10 ppb
2018-08-31AE39137ND
2018-10-10AE43255ND
2018-10-10AE43256ND
2018-10-10AE43254ND
2018-10-10AE43259ND
2018-11-26AE46856ND
2019-01-23AE50957ND
2019-01-23AE50951ND
2019-01-23AE50953ND
2019-01-23AE50955ND
2019-01-23AE50961ND
2019-01-23AE50940ND
2019-01-23AE50919ND
2019-01-23AE50920ND
2019-01-23AE50922ND
2019-04-08AE61372ND
2019-04-08AE61373ND
2019-04-08AE61368ND
2019-04-08AE61369ND
2019-07-26AE76147ND
2019-07-26AE76145ND
2019-07-26AE761481.000 ppb
2019-07-26AE76158ND
2019-10-15AE86628ND
2019-10-15AE86631ND
2019-10-15AE86633ND
2019-10-15AE86629ND