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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Seguin

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)

60

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20144.38 ppb1710ND - 22.5 ppb
201513.6 ppb1712ND - 89.1 ppb
201611.0 ppb1711ND - 44.0 ppb
20173.98 ppb179ND - 16.0 ppb
20184.89 ppb177ND - 22.7 ppb
20194.49 ppb1711ND - 12.1 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
2014-02-19AC43558ND
2014-02-19AC435881.40 ppb
2014-02-19AC435561.20 ppb
2014-02-19AC435546.70 ppb
2014-05-14AC54213ND
2014-05-14AC542172.00 ppb
2014-05-14AC542181.60 ppb
2014-05-14AC5420816.2 ppb
2014-07-23AC60694ND
2014-07-23AC60746ND
2014-07-23AC607962.20 ppb
2014-07-23AC60780ND
2014-07-23AC6074422.5 ppb
2014-10-03AC68884ND
2014-10-03AC688901.10 ppb
2014-10-03AC68892ND
2014-10-03AC6890619.6 ppb
2015-01-27AC77886ND
2015-01-27AC778831.80 ppb
2015-01-27AC778821.000 ppb
2015-01-27AC7790519.1 ppb
2015-04-15AC88349ND
2015-04-15AC883461.90 ppb
2015-04-15AC88343ND
2015-04-15AC8835312.3 ppb
2015-07-16AC9996049.0 ppb
2015-07-16AC99896ND
2015-07-16AC998842.50 ppb
2015-07-16AC998901.20 ppb
2015-07-16AC9988949.8 ppb
2015-11-12AD13323ND
2015-11-12AD133241.80 ppb
2015-11-12AD133291.60 ppb
2015-11-12AD1332589.1 ppb
2016-01-19AD18600ND
2016-01-19AD18598ND
2016-01-19AD18593ND
2016-01-19AD1859618.9 ppb
2016-04-06AD32039ND
2016-04-06AD320401.30 ppb
2016-04-06AD32041ND
2016-04-06AD3201123.0 ppb
2016-07-07AD4334744.0 ppb
2016-07-07AD432771.90 ppb
2016-07-07AD432753.50 ppb
2016-07-07AD432781.70 ppb
2016-07-07AD4327926.0 ppb
2016-10-06AD52647ND
2016-10-06AD5264327.6 ppb
2016-10-06AD526441.60 ppb
2016-10-06AD5264838.1 ppb
2017-02-07AD69156ND
2017-02-07AD691521.10 ppb
2017-02-07AD69154ND
2017-02-07AD691559.60 ppb
2017-05-08AD82978ND
2017-05-08AD82977ND
2017-05-08AD82985ND
2017-05-08AD8298310.6 ppb
2017-07-28AD9139716.0 ppb
2017-07-28AD91315ND
2017-07-28AD913301.30 ppb
2017-07-28AD913161.40 ppb
2017-07-28AD9132915.2 ppb
2017-10-05AD99538ND
2017-10-05AD995401.70 ppb
2017-10-05AD99539ND
2017-10-05AD9953710.7 ppb
2018-02-09AE13261ND
2018-02-09AE13240ND
2018-02-09AE13266ND
2018-02-09AE132392.70 ppb
2018-04-13AE22483ND
2018-04-13AE22484ND
2018-04-13AE22471ND
2018-04-13AE2247222.6 ppb
2018-08-09AE3638416.0 ppb
2018-08-09AE36307ND
2018-08-09AE363051.40 ppb
2018-08-09AE36308ND
2018-08-09AE3630116.3 ppb
2018-10-03AE42508ND
2018-10-03AE425041.50 ppb
2018-10-03AE42507ND
2018-10-03AE4250622.7 ppb
2019-01-23AE50911ND
2019-01-23AE50912ND
2019-01-23AE50913ND
2019-01-23AE5091410.00 ppb
2019-04-16AE62748ND
2019-04-16AE62744ND
2019-04-16AE62745ND
2019-04-16AE6274612.1 ppb
2019-07-22AE7536211.0 ppb
2019-07-22AE752533.30 ppb
2019-07-22AE753044.60 ppb
2019-07-22AE752544.00 ppb
2019-07-22AE7525512.0 ppb
2019-10-07AE857854.10 ppb
2019-10-07AE857833.40 ppb
2019-10-07AE8578910.7 ppb
2019-11-15AE895011.10 ppb