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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Hanford

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

 

88

Samples

0

Samples exceeding legal limit (MCL)

27

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
2014N/A00N/A
20151.48 ppb42ND - 4.50 ppb
20160.710 ppb299ND - 4.90 ppb
20171.51 ppb168ND - 4.90 ppb
20181.35 ppb124ND - 7.00 ppb
20190.415 ppb274ND - 4.80 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
2015-10-075810-901-1010ND
2015-10-075810-903-09154.50 ppb
2015-10-075810-900-10451.40 ppb
2015-10-075810-902-0839ND
2016-01-135810-903-08153.60 ppb
2016-01-135810-902-0845ND
2016-01-135810-900-09301.20 ppb
2016-01-135810-901-0900ND
2016-03-085810-043-1330ND
2016-03-085810-033-0945ND
2016-03-085810-036-1040ND
2016-03-085810-037-1100ND
2016-03-085810-042-1300ND
2016-03-085810-038-1000ND
2016-03-085810-039-0905ND
2016-03-095810-040-1125ND
2016-03-095810-041-0935ND
2016-03-095810-031-1025ND
2016-03-095810-028-1300ND
2016-03-105810-026-1300ND
2016-03-295810-034-0740ND
2016-04-145810-902-0905ND
2016-04-145810-903-08363.00 ppb
2016-04-145810-900-10171.000 ppb
2016-04-145810-901-0925ND
2016-07-125810-902-0845ND
2016-07-125810-903-08154.90 ppb
2016-07-125810-900-10151.40 ppb
2016-07-125810-901-09451.20 ppb
2016-10-125810-901-0941ND
2016-10-125810-902-0910ND
2016-10-125810-903-08303.20 ppb
2016-10-125810-900-10481.10 ppb
2017-01-115810-902-0852ND
2017-01-115810-903-08174.40 ppb
2017-01-115810-901-09401.10 ppb
2017-01-115810-900-10301.90 ppb
2017-04-135810-902-1002ND
2017-04-135810-903-09074.60 ppb
2017-04-135810-901-1044ND
2017-04-135810-900-11221.50 ppb
2017-07-125810-901-1015ND
2017-07-125810-902-0918ND
2017-07-125810-903-08404.90 ppb
2017-07-125810-900-10531.40 ppb
2017-10-125810-900-1002ND
2017-10-125810-902-0744ND
2017-10-125810-901-0923ND
2017-10-125810-903-08284.40 ppb
2018-01-115810-900-11582.00 ppb
2018-01-115810-903-10187.00 ppb
2018-01-115810-902-0905ND
2018-01-115810-901-1014ND
2018-07-135810-901-0925ND
2018-07-135810-903-08073.80 ppb
2018-07-135810-900-1000ND
2018-07-135810-902-0855ND
2018-10-115810-901-1020ND
2018-10-115810-903-09003.40 ppb
2018-10-115810-902-0940ND
2018-10-115810-900-1105ND
2019-01-105810-901-0935ND
2019-01-105810-902-0841ND
2019-01-105810-903-07584.80 ppb
2019-01-105810-900-1008ND
2019-03-135810-042-1125ND
2019-03-135810-043-0830ND
2019-03-135810-031-1210ND
2019-03-135810-033-1040ND
2019-03-145810-028-1005ND
2019-03-145810-037-1110ND
2019-03-145810-034-1040ND
2019-03-145810-036-1140ND
2019-03-145810-040-0840ND
2019-03-145810-041-0915ND
2019-04-105810-902-0810ND
2019-04-105810-901-0950ND
2019-04-105810-900-1120ND
2019-04-105810-903-09051.000 ppb
2019-05-095810-039-1100ND
2019-07-115810-902-1040ND
2019-07-115810-901-1120ND
2019-07-115810-900-1200ND
2019-07-115810-903-09502.50 ppb
2019-10-105810-902-0830ND
2019-10-105810-901-0915ND
2019-10-105810-900-0945ND
2019-10-105810-903-07352.90 ppb