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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

CTWC - Unionville System

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

 

165

Samples

0

Samples exceeding legal limit (MCL)

121

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
201422.0 ppb4331ND - 52.0 ppb
201519.2 ppb3118ND - 54.0 ppb
201614.4 ppb3017ND - 47.0 ppb
201712.6 ppb2420ND - 34.0 ppb
201830.8 ppb1918ND - 50.7 ppb
201936.2 ppb1817ND - 63.5 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
2014-01-21BG01724VOC10.550 ppb
2014-01-22BG01725VOC1ND
2014-01-22BG01726VOC10.500 ppb
2014-01-22BG017276VOC1ND
2014-01-22BG01727VOC1ND
2014-01-22BG01728VOC1ND
2014-01-22BG02299TTHM5.80 ppb
2014-01-23BG02294TTHM1.60 ppb
2014-01-23BG02295TTHM35.0 ppb
2014-01-23BG02296TTHM2.20 ppb
2014-01-23BG02297TTHM36.0 ppb
2014-01-23BG02298TTHM2.20 ppb
2014-01-23BG02300TTHM4.10 ppb
2014-01-31BG02295THM35.0 ppb
2014-01-31BG06715TTHM50.0 ppb
2014-01-31BG06716TTHM52.0 ppb
2014-01-31BG06717TTHM24.0 ppb
2014-01-31BG06718THM48.0 ppb
2014-01-31BG06718TTHM48.0 ppb
2014-02-12BG09383VOC17.80 ppb
2014-04-02BG26931VOC12.50 ppb
2014-04-03BG26932VOC1ND
2014-04-03BG26933VOC1ND
2014-04-22BG36625THM40.0 ppb
2014-04-22BG36625TTHM40.0 ppb
2014-04-22BG36626TTHM38.0 ppb
2014-04-22BG36627TTHM38.0 ppb
2014-04-22BG36628THM50.0 ppb
2014-04-22BG36628TTHM50.0 ppb
2014-07-09BG72399VOC1ND
2014-07-09BG72400VOC1ND
2014-07-09BG72401VOC1ND
2014-07-22BG81008TTHM44.0 ppb
2014-07-22BG81009TTHM38.0 ppb
2014-07-22BG81010TTHM47.0 ppb
2014-07-22BG81011TTHM51.0 ppb
2014-10-01BH22261VOC1ND
2014-10-16BH28261VOC1ND
2014-10-16BH28262VOC1ND
2014-10-22BH31458TTHM36.0 ppb
2014-10-22BH31459TTHM37.0 ppb
2014-10-22BH31460TTHM37.0 ppb
2014-10-22BH31461TTHM43.0 ppb
2015-01-07BH61112VOC1ND
2015-01-07BH61113VOC1ND
2015-01-07BH61114VOC1ND
2015-01-07BH61115VOC1ND
2015-01-07BH61116VOC1ND
2015-01-21BH66105TTHM36.0 ppb
2015-01-21BH66103TTHM37.0 ppb
2015-01-21BH66106TTHM45.0 ppb
2015-01-21BH66104TTHM41.0 ppb
2015-01-22BH66100VOC10.730 ppb
2015-04-27BJ08473TTHM41.0 ppb
2015-04-27BJ08472TTHM32.0 ppb
2015-04-28BJ08474TTHM47.0 ppb
2015-04-28BJ08471TTHM40.0 ppb
2015-04-28BJ08475VOC1ND
2015-04-28BJ08476VOC1ND
2015-05-05BJ12368VOC1ND
2015-07-15BJ47000VOC1ND
2015-07-15BJ47001VOC1ND
2015-07-20BJ60685TTHM43.0 ppb
2015-07-20BJ60682TTHM42.0 ppb
2015-07-20BJ60684TTHM54.0 ppb
2015-07-21BJ60686TTHM7.50 ppb
2015-08-05BJ69611VOC1ND
2015-10-05BK02871TTHM34.0 ppb
2015-10-05BK02873TTHM39.0 ppb
2015-10-06BK02872TTHM33.0 ppb
2015-10-06BK02876VOC12.20 ppb
2015-10-06BK02877VOC1ND
2015-10-06BK02878VOC1ND
2015-10-20BK11417TTHM20.0 ppb
2016-01-11BK51263TTHM22.0 ppb
2016-01-11BK51264TTHM23.0 ppb
2016-01-11BK51265TTHM26.0 ppb
2016-01-11BK51257VOC1ND
2016-01-11BK51258VOC1ND
2016-01-11BK51260VOC1ND
2016-01-11BK51261VOC1ND
2016-01-11BK51259VOC1ND
2016-01-18BK54312TTHM6.80 ppb
2016-04-11BN12525VOC1ND
2016-04-11BN12526VOC1ND
2016-04-11BN12527VOC1ND
2016-04-18BN15772TTHM38.0 ppb
2016-04-18BN15773TTHM39.0 ppb
2016-04-18BN15774TTHM30.0 ppb
2016-04-18BN15775TTHM21.0 ppb
2016-07-12BN71240TTHM30.0 ppb
2016-07-12BN71241TTHM4.30 ppb
2016-07-13BN72150TTHM47.0 ppb
2016-07-13BN72151TTHM31.0 ppb
2016-08-16BN92944VOC10.900 ppb
2016-08-16BN92945VOC1ND
2016-08-16BN92946VOC1ND
2016-10-04BV35900TTHM18.0 ppb
2016-10-04BV35901TTHM21.0 ppb
2016-10-04BV35905TTHM32.0 ppb
2016-10-11BV44240TTHM43.0 ppb
2016-10-24BV62669VOC1ND
2016-10-24BV62670VOC1ND
2016-11-01BV72457VOC1ND
2017-01-17BX30317TTHM22.0 ppb
2017-01-17BX30318TTHM15.0 ppb
2017-01-17BX30319TTHM16.0 ppb
2017-01-17BX30320TTHM21.0 ppb
2017-04-11BY02319TTHM21.0 ppb
2017-04-11BY02320TTHM18.0 ppb
2017-04-11BY02321TTHM23.0 ppb
2017-04-11BY02322TTHM28.0 ppb
2017-05-23BY28459VOC13.90 ppb
2017-07-18BY63323TTHM26.0 ppb
2017-07-18BY63324TTHM0.750 ppb
2017-07-18BY63325TTHM32.0 ppb
2017-07-18BY63326TTHM34.0 ppb
2017-07-25BY71391VOC11.10 ppb
2017-07-25BY71392VOC1ND
2017-07-25BY71394VOC1ND
2017-07-25BY71393VOC11.30 ppb
2017-08-15BY84216VOC1ND
2017-10-24BZ26033TTHM3.00 ppb
2017-10-24BZ26034TTHM6.00 ppb
2017-10-24BZ26035TTHM24.0 ppb
2017-10-24BZ26036TTHM4.60 ppb
2017-10-27BZ28354VOC11.80 ppb
2017-11-28BZ47211VOC1ND
2018-01-16BZ73286TTHM33.0 ppb
2018-01-16BZ73287TTHM26.0 ppb
2018-01-16BZ73288TTHM32.0 ppb
2018-01-16BZ73289TTHM36.0 ppb
2018-04-27CA37381TTHM31.0 ppb
2018-04-27CA37382TTHM30.0 ppb
2018-04-27CA37383TTHM34.0 ppb
2018-04-27CA37384TTHM39.0 ppb
2018-07-23CA967420.830 ppb
2018-07-23CA96743ND
2018-07-24CA9673439.0 ppb
2018-07-24CA9673536.0 ppb
2018-07-24CA9673643.0 ppb
2018-07-24CA9673743.0 ppb
2018-07-31CB013603.20 ppb
2018-10-02DBP 20050766539.6 ppb
2018-10-02DBP 20050766629.0 ppb
2018-10-02DBP 20050766750.7 ppb
2018-10-02DBP 20050802039.6 ppb
2019-01-08DBP 20051813058.4 ppb
2019-01-08DBP 20051813620.9 ppb
2019-01-08DBP 20051813946.6 ppb
2019-01-08DBP 20051814352.0 ppb
2019-01-29VOC1 200520002ND
2019-01-29VOC1 2005199970.900 ppb
2019-04-09DBP 20052784629.0 ppb
2019-04-09DBP 20052784710.4 ppb
2019-04-09DBP 20052784848.0 ppb
2019-04-09DBP 20052784916.9 ppb
2019-07-02DBP 20053898641.7 ppb
2019-07-02DBP 20053898750.8 ppb
2019-07-02DBP 20053898839.5 ppb
2019-07-02DBP 20053898946.3 ppb
2019-10-08DBP 20055201238.9 ppb
2019-10-08DBP 20055201363.5 ppb
2019-10-08DBP 20055201441.0 ppb
2019-10-08DBP 20055201547.6 ppb