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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Montgomery County MUD 60

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

 

96

Samples

0

Samples exceeding legal limit (MCL)

62

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND160ND
2015ND160ND
201639.8 ppb161611.6 ppb - 80.7 ppb
201735.9 ppb16165.60 ppb - 76.9 ppb
201813.8 ppb161610.1 ppb - 17.4 ppb
201910.4 ppb1614ND - 19.9 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
2014-02-21AC44192ND
2014-02-21AC44247ND
2014-02-21AC44251ND
2014-02-21AC44188ND
2014-04-28AC51855ND
2014-04-28AC51853ND
2014-04-28AC51856ND
2014-04-28AC51859ND
2014-07-14AC59596ND
2014-07-14AC59593ND
2014-07-14AC59571ND
2014-07-14AC59584ND
2014-10-27AC70589ND
2014-10-27AC70565ND
2014-10-27AC70564ND
2014-10-27AC70567ND
2015-02-24AC81653ND
2015-02-24AC81644ND
2015-02-24AC81646ND
2015-02-24AC81640ND
2015-05-01AC90281ND
2015-05-01AC90285ND
2015-05-01AC90283ND
2015-05-01AC90279ND
2015-07-14AC99352ND
2015-07-14AC99367ND
2015-07-14AC99366ND
2015-07-14AC99354ND
2015-10-15AD10795ND
2015-10-15AD10788ND
2015-10-15AD10789ND
2015-10-15AD10787ND
2016-03-09AD2786815.6 ppb
2016-03-09AD2785511.9 ppb
2016-03-09AD2785318.8 ppb
2016-03-09AD2785611.6 ppb
2016-05-19AD3743921.3 ppb
2016-05-19AD3743319.8 ppb
2016-05-19AD3744928.3 ppb
2016-05-19AD3743425.0 ppb
2016-09-28AD5184456.1 ppb
2016-09-28AD5185351.5 ppb
2016-09-29AD5198349.0 ppb
2016-09-29AD5198246.8 ppb
2016-11-02AD5642275.2 ppb
2016-11-02AD5642853.0 ppb
2016-11-03AD5643571.8 ppb
2016-11-03AD5643180.7 ppb
2017-01-25AD6672776.9 ppb
2017-01-25AD6673452.4 ppb
2017-03-09AD7433659.5 ppb
2017-03-09AD7433867.9 ppb
2017-04-20AD8036136.4 ppb
2017-04-20AD8036235.4 ppb
2017-04-20AD8035332.4 ppb
2017-04-20AD8036533.1 ppb
2017-07-13AD8921839.1 ppb
2017-07-13AD8921135.9 ppb
2017-07-13AD8922540.6 ppb
2017-07-13AD8921638.2 ppb
2017-11-02AE034036.40 ppb
2017-11-02AE033975.60 ppb
2017-11-02AE034076.60 ppb
2017-11-02AE034117.80 ppb
2018-02-08AE1297313.0 ppb
2018-02-08AE1297111.0 ppb
2018-02-08AE1299412.4 ppb
2018-02-08AE1295612.7 ppb
2018-05-24AE2769614.4 ppb
2018-05-24AE2767115.8 ppb
2018-05-24AE2744214.6 ppb
2018-05-24AE2769516.1 ppb
2018-09-13AE4001111.2 ppb
2018-09-13AE4000610.1 ppb
2018-09-13AE4001011.2 ppb
2018-09-13AE4000812.7 ppb
2018-11-20AE4663317.0 ppb
2018-11-20AE4663415.2 ppb
2018-11-20AE4663717.4 ppb
2018-11-20AE4663515.9 ppb
2019-03-06AE5734315.2 ppb
2019-03-06AE5734013.5 ppb
2019-03-06AE5733712.9 ppb
2019-03-06AE5733814.8 ppb
2019-05-23AE679248.60 ppb
2019-05-23AE679357.80 ppb
2019-05-23AE679297.20 ppb
2019-05-23AE679336.60 ppb
2019-09-16AE83595ND
2019-09-16AE836112.10 ppb
2019-09-16AE835881.000 ppb
2019-09-30AE85051ND
2019-11-26AE9056919.3 ppb
2019-11-26AE9057718.1 ppb
2019-11-26AE9058118.6 ppb
2019-11-26AE9057119.9 ppb