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Chloroform

Watertown City

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.

 

142

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201051.2 ppb161615.0 ppb - 110.0 ppb
201175.3 ppb121249.0 ppb - 150.0 ppb
201263.4 ppb161623.0 ppb - 118.0 ppb
201360.6 ppb161616.0 ppb - 140.0 ppb
201455.2 ppb34342.80 ppb - 129.0 ppb
201545.0 ppb484813.0 ppb - 97.0 ppb

ppb = parts per billion.

State and national drinking water standards and health guidelines

Health Guideline 0.4 ppb

The 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.

EPA Maximum Contaminant
Level Goal (MCLG)70.0 ppb

A non-enforceable federal health guideline. For cancer-causing chemicals, these health goals are typically set to zero.

ppb = parts per billion.

All test results

Date Lab ID Result
2010-02-111002459-00316.0 ppb
2010-02-111002459-00115.0 ppb
2010-02-111002459-00434.0 ppb
2010-02-111002459-00216.0 ppb
2010-05-131007613-00474.0 ppb
2010-05-131007613-00350.0 ppb
2010-05-131007613-00140.0 ppb
2010-05-131007613-00240.0 ppb
2010-08-131013847-00381.0 ppb
2010-08-131013847-004110.0 ppb
2010-08-131013847-00189.0 ppb
2010-08-131013847-00267.0 ppb
2010-11-09101957-00136.0 ppb
2010-11-091019574-00350.0 ppb
2010-11-091019574-00234.0 ppb
2010-11-091019574-00467.0 ppb
2011-05-111106553-00160.0 ppb
2011-05-111106553-00260.0 ppb
2011-05-111106553-00498.0 ppb
2011-05-111106553-00367.0 ppb
2011-08-031112110-003100.0 ppb
2011-08-031112110-004150.0 ppb
2011-08-031112110-00280.0 ppb
2011-08-031112110-00164.0 ppb
2011-11-141118448-00154.0 ppb
2011-11-141118448-00355.0 ppb
2011-11-141118448-00249.0 ppb
2011-11-141118448-00467.0 ppb
2012-02-221202714-00444.0 ppb
2012-02-221202714-00327.0 ppb
2012-02-221202714-00223.0 ppb
2012-02-221202714-00141.0 ppb
2012-05-021206534-00350.0 ppb
2012-05-021206534-00171.0 ppb
2012-05-021206534-00475.0 ppb
2012-05-021026534-00249.0 ppb
2012-08-011212371-00291.0 ppb
2012-08-011212371-00972.0 ppb
2012-08-011212371-006118.0 ppb
2012-08-011212371-010100.0 ppb
2012-11-071218302-00684.0 ppb
2012-11-071218302-00945.0 ppb
2012-11-071218302-01054.0 ppb
2012-11-071218302-00270.0 ppb
2013-02-061301770-00716.0 ppb
2013-02-061301770-00647.0 ppb
2013-02-061301770-00823.0 ppb
2013-02-061301770-00222.0 ppb
2013-05-08MRT0031 DBP 2QTR1375.0 ppb
2013-05-08DS00014 DBP 2QTR1354.0 ppb
2013-05-08DS00026 DBP 2QTR1355.0 ppb
2013-05-08DS00015 2QTR201358.0 ppb
2013-08-061313147-004140.0 ppb
2013-08-061313147-003131.0 ppb
2013-08-071313147-00286.0 ppb
2013-08-081313147-00173.0 ppb
2013-11-061318290-01243.0 ppb
2013-11-061318290-01140.0 ppb
2013-11-061318290-00757.0 ppb
2013-11-061318290-01049.0 ppb
2014-02-051401657-01214.0 ppb
2014-02-051401657-01114.0 ppb
2014-02-051401657-01015.0 ppb
2014-02-051401657-00722.0 ppb
2014-02-051401657-0132.80 ppb
2014-04-021404398-00922.0 ppb
2014-05-071406257-01135.0 ppb
2014-05-071406257-01237.0 ppb
2014-05-071406257-00143.0 ppb
2014-05-071406257-00437.0 ppb
2014-07-161410755-01181.0 ppb
2014-07-161410755-01271.0 ppb
2014-07-161410755-01093.0 ppb
2014-07-161410755-007129.0 ppb
2014-08-061412351-007105.0 ppb
2014-08-061412351-01274.0 ppb
2014-08-061412351-01177.0 ppb
2014-08-061412351-01089.0 ppb
2014-09-101414832-00997.0 ppb
2014-09-101414832-01165.0 ppb
2014-09-101414832-00878.0 ppb
2014-09-101414832-01267.0 ppb
2014-10-081416618-01247.0 ppb
2014-10-081416618-01044.0 ppb
2014-10-081416618-01145.0 ppb
2014-10-081416618-00766.0 ppb
2014-11-051418303-01068.0 ppb
2014-11-051418303-00785.0 ppb
2014-11-051418303-01149.0 ppb
2014-11-051418303-01257.0 ppb
2014-12-031419724-01235.0 ppb
2014-12-031419724-01133.0 ppb
2014-12-031419724-00826.0 ppb
2014-12-031419724-00953.0 ppb
2015-01-141500772-01018.0 ppb
2015-01-141500772-01214.0 ppb
2015-01-151500772-01113.0 ppb
2015-01-151500772-00725.0 ppb
2015-02-041501522-01114.0 ppb
2015-02-041501522-00822.0 ppb
2015-02-041501522-01216.0 ppb
2015-02-041501522-00923.0 ppb
2015-03-041502825-01019.0 ppb
2015-03-041502825-01116.0 ppb
2015-03-041502825-01214.0 ppb
2015-03-041502825-00725.0 ppb
2015-04-081504564-01220.0 ppb
2015-04-081504564-01022.0 ppb
2015-04-081504564-01119.0 ppb
2015-04-081504564-00723.0 ppb
2015-05-061506084-01251.0 ppb
2015-05-061506084-01051.0 ppb
2015-05-061506084-00750.0 ppb
2015-05-061506084-01151.0 ppb
2015-06-031507791-01234.0 ppb
2015-06-031507791-01033.0 ppb
2015-06-031507791-01145.0 ppb
2015-06-031507791-00749.0 ppb
2015-07-081510103-01164.0 ppb
2015-07-081510103-01261.0 ppb
2015-07-081510103-01066.0 ppb
2015-07-081510103-00797.0 ppb
2015-08-051511980-01262.0 ppb
2015-08-051511980-01159.0 ppb
2015-08-051511980-00785.0 ppb
2015-08-051511980-01068.0 ppb
2015-09-091514301-01097.0 ppb
2015-09-091514301-01275.0 ppb
2015-09-091514301-01173.0 ppb
2015-09-091514301-00788.0 ppb
2015-10-071516030-01243.0 ppb
2015-10-071516030-01139.0 ppb
2015-10-071516030-00644.0 ppb
2015-10-071516030-00956.0 ppb
2015-11-041517576-01067.0 ppb
2015-11-041517576-01146.0 ppb
2015-11-041517576-00763.0 ppb
2015-11-041517576-01247.0 ppb
2015-12-021519086-01135.0 ppb
2015-12-021519086-01240.0 ppb
2015-12-021519086-00757.0 ppb
2015-12-021519086-01062.0 ppb