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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

City of South Houston

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.

 

108

Samples

0

Samples exceeding legal limit (MCL)

103

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20128.76 ppb1311ND - 29.0 ppb
201311.7 ppb16169.10 ppb - 16.0 ppb
201411.0 ppb1613ND - 32.9 ppb
201523.9 ppb212111.0 ppb - 56.0 ppb
201620.0 ppb212113.0 ppb - 31.9 ppb
201717.8 ppb21219.00 ppb - 27.6 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
2012-02-06AB8023729.0 ppb
2012-05-18AB902519.50 ppb
2012-05-18AB9026417.7 ppb
2012-05-18AB902545.10 ppb
2012-05-18AB90250ND
2012-07-06AB946801.30 ppb
2012-07-06AB946622.20 ppb
2012-07-06AB946634.00 ppb
2012-07-06AB94679ND
2012-10-12AC0320615.4 ppb
2012-10-12AC0321814.4 ppb
2012-10-12AC0320713.3 ppb
2012-10-12AC032192.00 ppb
2013-01-14AC075739.50 ppb
2013-01-14AC075679.60 ppb
2013-01-14AC075749.10 ppb
2013-01-14AC075689.60 ppb
2013-04-02AC1546711.9 ppb
2013-04-02AC1545712.2 ppb
2013-04-02AC1546012.1 ppb
2013-04-02AC1546312.2 ppb
2013-07-19AC2531611.2 ppb
2013-07-19AC2532111.6 ppb
2013-07-19AC2528511.6 ppb
2013-07-19AC2532210.8 ppb
2013-10-24AC3322814.5 ppb
2013-10-24AC3322116.0 ppb
2013-10-24AC3320313.7 ppb
2013-10-24AC3320211.7 ppb
2014-02-14AC4309115.8 ppb
2014-02-14AC4306814.7 ppb
2014-02-14AC4307015.5 ppb
2014-02-14AC4302314.6 ppb
2014-04-07AC4961217.8 ppb
2014-04-07AC4961518.2 ppb
2014-04-07AC4958218.8 ppb
2014-06-06AC5629811.6 ppb
2014-08-11AC62901ND
2014-08-11AC6292932.9 ppb
2014-08-11AC629001.50 ppb
2014-08-11AC629021.20 ppb
2014-11-24AC72786ND
2014-11-24AC7272010.9 ppb
2014-11-24AC72782ND
2014-11-24AC727871.90 ppb
2015-01-21AC7710112.0 ppb
2015-01-21AC7709512.0 ppb
2015-01-21AC7709311.0 ppb
2015-01-21AC7709912.0 ppb
2015-01-21AC7710913.0 ppb
2015-01-21AC7720211.7 ppb
2015-01-21AC7720411.5 ppb
2015-01-21AC7720913.0 ppb
2015-01-21AC7720312.1 ppb
2015-06-12AC9589941.1 ppb
2015-06-12AC9590050.6 ppb
2015-06-12AC9592744.9 ppb
2015-06-12AC9590756.0 ppb
2015-07-20AD0012129.4 ppb
2015-07-20AD0007732.4 ppb
2015-07-20AD0010530.8 ppb
2015-07-20AD0010026.7 ppb
2015-10-06AD0959020.9 ppb
2015-10-06AD0958514.7 ppb
2015-10-06AD0959221.0 ppb
2015-10-06AD0958124.5 ppb
2016-01-14AD1820716.0 ppb
2016-01-14AD1820517.0 ppb
2016-01-14AD1822113.0 ppb
2016-01-14AD1821916.0 ppb
2016-01-14AD1821516.0 ppb
2016-01-14AD1816518.2 ppb
2016-01-14AD1816321.4 ppb
2016-01-14AD1816418.4 ppb
2016-01-14AD1816222.2 ppb
2016-04-08AD3254120.7 ppb
2016-04-08AD3254621.6 ppb
2016-04-08AD3252822.7 ppb
2016-04-08AD3253518.8 ppb
2016-07-11AD4351529.9 ppb
2016-07-11AD4352231.9 ppb
2016-07-11AD4351628.0 ppb
2016-07-11AD4355529.0 ppb
2016-10-07AD5279414.4 ppb
2016-10-07AD5279815.4 ppb
2016-10-07AD5279616.1 ppb
2016-10-07AD5279514.1 ppb
2017-01-06AD636179.80 ppb
2017-01-06AD635619.00 ppb
2017-01-06AD6356011.3 ppb
2017-01-06AD6356310.00 ppb
2017-01-06AD635629.70 ppb
2017-03-01AD7278520.0 ppb
2017-03-01AD7276318.0 ppb
2017-03-01AD7276522.0 ppb
2017-03-01AD7275316.0 ppb
2017-04-07AD7891222.3 ppb
2017-04-07AD7891127.6 ppb
2017-04-07AD7891022.5 ppb
2017-04-07AD7891326.0 ppb
2017-07-14AD8941416.7 ppb
2017-07-14AD8941718.4 ppb
2017-07-14AD8941917.1 ppb
2017-07-14AD8941516.0 ppb
2017-10-17AE0105918.9 ppb
2017-10-17AE0105623.2 ppb
2017-10-17AE0106018.6 ppb
2017-10-17AE0107120.8 ppb