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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Alamo

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

 

102

Samples

0

Samples exceeding legal limit (MCL)

10

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.347 ppb174ND - 1.60 ppb
2015ND170ND
20160.118 ppb172ND - 1.000 ppb
2017ND170ND
2018ND170ND
20190.324 ppb174ND - 1.80 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
2014-02-28AC452601.40 ppb
2014-02-28AC452641.40 ppb
2014-02-28AC452961.50 ppb
2014-02-28AC453221.60 ppb
2014-04-22AC51361ND
2014-04-22AC51360ND
2014-04-22AC51356ND
2014-04-22AC51359ND
2014-07-23AC60710ND
2014-07-23AC60758ND
2014-07-23AC60754ND
2014-07-23AC60757ND
2014-07-23AC60755ND
2014-10-21AC70171ND
2014-10-21AC70156ND
2014-10-21AC70170ND
2014-10-21AC70157ND
2015-01-21AC77196ND
2015-01-21AC77200ND
2015-01-21AC77198ND
2015-01-21AC77199ND
2015-04-07AC87462ND
2015-04-07AC87457ND
2015-04-07AC87451ND
2015-04-07AC87482ND
2015-07-14AC99403ND
2015-07-14AC99330ND
2015-07-14AC99333ND
2015-07-14AC99334ND
2015-07-14AC99327ND
2015-10-20AD11161ND
2015-10-20AD11158ND
2015-10-20AD11156ND
2015-10-20AD11166ND
2016-03-02AD26623ND
2016-03-02AD26625ND
2016-03-02AD26618ND
2016-03-02AD26619ND
2016-06-08AD39748ND
2016-06-08AD39749ND
2016-06-08AD39714ND
2016-06-08AD39708ND
2016-07-14AD44287ND
2016-07-14AD44231ND
2016-07-14AD44218ND
2016-07-14AD44217ND
2016-07-14AD44222ND
2016-11-15AD579821.000 ppb
2016-11-15AD58006ND
2016-11-15AD580081.000 ppb
2016-11-15AD58003ND
2017-01-10AD63926ND
2017-01-10AD63925ND
2017-01-10AD63924ND
2017-01-10AD63938ND
2017-05-01AD81755ND
2017-05-01AD81776ND
2017-05-01AD81756ND
2017-05-01AD81779ND
2017-07-12AD89091ND
2017-07-12AD89050ND
2017-07-12AD89052ND
2017-07-12AD89056ND
2017-07-12AD89053ND
2017-10-31AE02899ND
2017-10-31AE02919ND
2017-10-31AE02915ND
2017-10-31AE02918ND
2018-01-24AE10149ND
2018-01-24AE10148ND
2018-01-24AE10143ND
2018-01-24AE10151ND
2018-04-11AE22046ND
2018-04-11AE22045ND
2018-04-11AE22037ND
2018-04-11AE22039ND
2018-08-16AE37383ND
2018-08-16AE37326ND
2018-08-16AE37328ND
2018-08-16AE37325ND
2018-08-16AE37334ND
2018-10-10AE43061ND
2018-10-10AE43078ND
2018-10-10AE43077ND
2018-10-10AE43054ND
2019-02-26AE55945ND
2019-02-26AE55941ND
2019-02-26AE55943ND
2019-02-26AE55949ND
2019-05-21AE67340ND
2019-05-21AE67336ND
2019-05-21AE67339ND
2019-05-21AE67347ND
2019-09-04AE82077ND
2019-09-04AE820181.30 ppb
2019-09-04AE820111.20 ppb
2019-09-04AE820201.80 ppb
2019-09-04AE820131.20 ppb
2019-11-07AE88868ND
2019-11-07AE88870ND
2019-11-07AE88875ND
2019-11-07AE88873ND