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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Atascosa Rural WSC

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)

6

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.0833 ppb181ND - 1.50 ppb
20150.0889 ppb181ND - 1.60 ppb
20160.211 ppb182ND - 2.70 ppb
20170.0700 ppb201ND - 1.40 ppb
2018ND200ND
20190.0579 ppb191ND - 1.10 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
2014-02-12AC42474ND
2014-02-12AC42455ND
2014-02-12AC42452ND
2014-02-12AC42465ND
2014-02-12AC42464ND
2014-03-27AC48533ND
2014-04-16AC50803ND
2014-04-16AC50806ND
2014-04-16AC50804ND
2014-04-16AC50805ND
2014-07-21AC60364ND
2014-07-21AC60365ND
2014-07-21AC60363ND
2014-07-21AC60362ND
2014-10-15AC697741.50 ppb
2014-10-15AC69782ND
2014-10-15AC69773ND
2014-10-15AC69775ND
2015-02-05AC79472ND
2015-02-05AC79470ND
2015-02-05AC79427ND
2015-02-05AC79431ND
2015-02-05AC79459ND
2015-02-05AC79430ND
2015-06-02AC942811.60 ppb
2015-06-02AC94279ND
2015-06-02AC94282ND
2015-06-02AC94270ND
2015-08-10AD03200ND
2015-08-10AD03209ND
2015-08-10AD03207ND
2015-08-10AD03206ND
2015-10-06AD09594ND
2015-10-06AD09597ND
2015-10-06AD09577ND
2015-10-06AD09595ND
2016-02-16AD23667ND
2016-02-16AD23635ND
2016-02-16AD23605ND
2016-02-16AD23604ND
2016-02-16AD23606ND
2016-02-16AD23602ND
2016-04-26AD341522.70 ppb
2016-04-26AD34168ND
2016-04-26AD34170ND
2016-04-26AD34171ND
2016-07-13AD44024ND
2016-07-13AD44023ND
2016-07-13AD44003ND
2016-07-13AD44008ND
2016-10-10AD52808ND
2016-10-10AD528091.10 ppb
2016-10-10AD52811ND
2016-10-10AD52804ND
2017-01-12AD64758ND
2017-01-12AD64790ND
2017-01-12AD64724ND
2017-01-12AD64703ND
2017-01-12AD64700ND
2017-01-12AD64699ND
2017-04-06AD78718ND
2017-04-06AD78719ND
2017-04-06AD78720ND
2017-04-06AD78721ND
2017-07-18AD89944ND
2017-07-18AD89939ND
2017-07-18AD89940ND
2017-07-18AD89935ND
2017-08-09AD92562ND
2017-10-06AD997541.40 ppb
2017-10-06AD99751ND
2017-10-06AD99753ND
2017-10-06AD99752ND
2017-10-06AD99826ND
2018-01-18AE09251ND
2018-01-18AE09255ND
2018-01-18AE09253ND
2018-01-18AE09229ND
2018-01-18AE09221ND
2018-01-18AE09210ND
2018-01-18AE09215ND
2018-04-06AE21722ND
2018-04-06AE21680ND
2018-04-06AE21679ND
2018-04-06AE21678ND
2018-04-06AE21677ND
2018-08-01AE35273ND
2018-08-01AE35274ND
2018-08-01AE35276ND
2018-08-01AE35275ND
2018-10-04AE42677ND
2018-10-04AE42679ND
2018-10-04AE42676ND
2018-10-04AE42678ND
2019-01-11AE49573ND
2019-01-11AE49571ND
2019-01-11AE49569ND
2019-03-05AE57111ND
2019-03-05AE57110ND
2019-03-05AE57108ND
2019-03-05AE57109ND
2019-04-04AE61170ND
2019-04-04AE61171ND
2019-04-04AE61169ND
2019-04-04AE61172ND
2019-07-10AE74128ND
2019-07-10AE74133ND
2019-07-10AE741321.10 ppb
2019-07-10AE74129ND
2019-10-01AE85330ND
2019-10-01AE85329ND
2019-10-01AE85327ND
2019-10-01AE85332ND