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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Orange Water & Sewer Authority

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

 

192

Samples

0

Samples exceeding legal limit (MCL)

192

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
201422.6 ppb323215.0 ppb - 31.0 ppb
201513.6 ppb32326.80 ppb - 21.0 ppb
201616.7 ppb32326.20 ppb - 31.0 ppb
201715.7 ppb32327.10 ppb - 23.0 ppb
201813.7 ppb32326.30 ppb - 25.0 ppb
201911.4 ppb32325.70 ppb - 17.0 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
2014-02-11297137329.0 ppb
2014-02-11297137429.0 ppb
2014-02-11297137527.0 ppb
2014-02-11297137630.0 ppb
2014-02-11297137729.0 ppb
2014-02-11297137829.0 ppb
2014-02-11297137927.0 ppb
2014-02-11297138017.0 ppb
2014-05-13302529118.0 ppb
2014-05-13302529221.0 ppb
2014-05-13302529318.0 ppb
2014-05-13302529419.0 ppb
2014-05-13302529519.0 ppb
2014-05-13302529618.0 ppb
2014-05-13302529719.0 ppb
2014-05-13302529817.0 ppb
2014-08-12308166925.0 ppb
2014-08-12308167031.0 ppb
2014-08-12308167121.0 ppb
2014-08-12308167228.0 ppb
2014-08-12308167329.0 ppb
2014-08-12308167427.0 ppb
2014-08-12308167526.0 ppb
2014-08-12308167624.0 ppb
2014-11-12313805616.0 ppb
2014-11-12313805718.0 ppb
2014-11-12313805819.0 ppb
2014-11-12313805921.0 ppb
2014-11-12313806021.0 ppb
2014-11-12313806120.0 ppb
2014-11-12313806217.0 ppb
2014-11-12313806315.0 ppb
2015-02-107.60 ppb
2015-02-108.50 ppb
2015-02-106.80 ppb
2015-02-108.80 ppb
2015-02-108.40 ppb
2015-02-108.00 ppb
2015-02-108.20 ppb
2015-02-107.10 ppb
2015-05-1214.0 ppb
2015-05-1217.0 ppb
2015-05-1217.0 ppb
2015-05-1216.0 ppb
2015-05-1215.0 ppb
2015-05-1216.0 ppb
2015-05-1214.0 ppb
2015-05-1214.0 ppb
2015-08-1117.0 ppb
2015-08-1121.0 ppb
2015-08-1115.0 ppb
2015-08-1121.0 ppb
2015-08-1120.0 ppb
2015-08-1118.0 ppb
2015-08-1119.0 ppb
2015-08-1114.0 ppb
2015-11-1011.0 ppb
2015-11-1014.0 ppb
2015-11-1012.0 ppb
2015-11-1013.0 ppb
2015-11-1014.0 ppb
2015-11-1014.0 ppb
2015-11-1013.0 ppb
2015-11-1012.0 ppb
2016-02-1634017147.20 ppb
2016-02-1634017158.50 ppb
2016-02-1634017168.50 ppb
2016-02-1634017178.00 ppb
2016-02-1634017187.90 ppb
2016-02-1634017198.30 ppb
2016-02-1634017207.00 ppb
2016-02-1634017216.20 ppb
2016-05-10344621415.0 ppb
2016-05-10344621514.0 ppb
2016-05-10344621617.0 ppb
2016-05-10344621717.0 ppb
2016-05-10344621814.0 ppb
2016-05-10344621916.0 ppb
2016-05-10344622015.0 ppb
2016-05-12344784215.0 ppb
2016-08-16352407024.0 ppb
2016-08-16352407127.0 ppb
2016-08-16352407230.0 ppb
2016-08-16352407328.0 ppb
2016-08-16352407427.0 ppb
2016-08-16352407531.0 ppb
2016-08-16352407628.0 ppb
2016-08-16352407730.0 ppb
2016-11-15358721014.0 ppb
2016-11-15358721117.0 ppb
2016-11-15358721215.0 ppb
2016-11-15358721319.0 ppb
2016-11-15358721417.0 ppb
2016-11-15358721516.0 ppb
2016-11-15358721614.0 ppb
2016-11-15358721713.0 ppb
2017-02-2136423817.20 ppb
2017-02-2136423827.90 ppb
2017-02-2136423837.30 ppb
2017-02-2136423849.10 ppb
2017-02-2136423858.10 ppb
2017-02-2136423867.60 ppb
2017-02-2136423877.10 ppb
2017-02-2136423887.20 ppb
2017-05-16369564720.0 ppb
2017-05-16369564822.0 ppb
2017-05-16369564920.0 ppb
2017-05-16369565021.0 ppb
2017-05-16369565123.0 ppb
2017-05-16369565221.0 ppb
2017-05-16369565319.0 ppb
2017-05-16369565418.0 ppb
2017-08-15375786920.0 ppb
2017-08-15375787023.0 ppb
2017-08-15375787121.0 ppb
2017-08-15375787223.0 ppb
2017-08-15375787322.0 ppb
2017-08-15375787423.0 ppb
2017-08-15375787521.0 ppb
2017-08-15375787620.0 ppb
2017-11-14382078911.0 ppb
2017-11-14382079015.0 ppb
2017-11-1438207919.60 ppb
2017-11-14382079217.0 ppb
2017-11-14382079314.0 ppb
2017-11-14382079415.0 ppb
2017-11-14382079513.0 ppb
2017-11-1438207969.00 ppb
2018-02-133871497 7.80 ppb
2018-02-133871498 7.40 ppb
2018-02-133871499 8.00 ppb
2018-02-133871500 7.80 ppb
2018-02-133871501 7.70 ppb
2018-02-133871502 7.30 ppb
2018-02-133871503 7.20 ppb
2018-02-133871504 6.30 ppb
2018-05-153937742 15.0 ppb
2018-05-153937743 15.0 ppb
2018-05-153937744 13.0 ppb
2018-05-153937745 16.0 ppb
2018-05-153937746 13.0 ppb
2018-05-153937747 14.0 ppb
2018-05-153937748 14.0 ppb
2018-05-153937749 13.0 ppb
2018-08-144022637 16.0 ppb
2018-08-144022638 19.0 ppb
2018-08-144022639 19.0 ppb
2018-08-144022640 19.0 ppb
2018-08-144022641 18.0 ppb
2018-08-144022642 18.0 ppb
2018-08-144022643 22.0 ppb
2018-08-144022644 25.0 ppb
2018-11-134121600 12.0 ppb
2018-11-134121601 16.0 ppb
2018-11-134121602 13.0 ppb
2018-11-134121603 16.0 ppb
2018-11-134121604 15.0 ppb
2018-11-134121605 15.0 ppb
2018-11-134121606 13.0 ppb
2018-11-134121607 10.00 ppb
2019-02-124195886-1 7.20 ppb
2019-02-124195887-1 7.80 ppb
2019-02-124195888-1 6.40 ppb
2019-02-124195889-1 8.00 ppb
2019-02-124195890-1 7.60 ppb
2019-02-124195891-1 7.70 ppb
2019-02-124195892-1 7.30 ppb
2019-02-124195893-1 6.70 ppb
2019-05-144294458 15.0 ppb
2019-05-144294459 17.0 ppb
2019-05-144294460 13.0 ppb
2019-05-144294461 17.0 ppb
2019-05-144294462 17.0 ppb
2019-05-144294463 17.0 ppb
2019-05-144294464 17.0 ppb
2019-05-144294465 17.0 ppb
2019-08-134386071 13.0 ppb
2019-08-134386072 17.0 ppb
2019-08-134386073 14.0 ppb
2019-08-134386074 17.0 ppb
2019-08-134386075 17.0 ppb
2019-08-134386076 16.0 ppb
2019-08-134386077 14.0 ppb
2019-08-134386078 14.0 ppb
2019-11-114482781 5.70 ppb
2019-11-114482782 6.90 ppb
2019-11-114482783 7.40 ppb
2019-11-114482784 8.40 ppb
2019-11-114482785 6.90 ppb
2019-11-114482786 7.00 ppb
2019-11-114482787 6.80 ppb
2019-11-114482788 5.80 ppb