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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Concord Water Department

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

 

113

Samples

0

Samples exceeding legal limit (MCL)

85

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.969 ppb116ND - 3.60 ppb
20155.03 ppb2318ND - 38.0 ppb
20166.26 ppb2319ND - 55.0 ppb
20171.78 ppb106ND - 9.20 ppb
20185.69 ppb2318ND - 61.0 ppb
20197.13 ppb2318ND - 54.9 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 Result
2014-02-041.80 ppb
2014-05-050.960 ppb
2014-07-011.10 ppb
2014-07-15ND
2014-07-15ND
2014-07-151.50 ppb
2014-07-28ND
2014-08-041.70 ppb
2014-08-13ND
2014-08-25ND
2014-11-043.60 ppb
2015-02-044.20 ppb
2015-02-041.30 ppb
2015-02-041.30 ppb
2015-02-042.40 ppb
2015-05-041.000 ppb
2015-05-042.30 ppb
2015-05-048.50 ppb
2015-05-040.700 ppb
2015-07-011.50 ppb
2015-07-15ND
2015-07-16ND
2015-07-16ND
2015-07-23ND
2015-08-031.000 ppb
2015-08-0338.0 ppb
2015-08-030.800 ppb
2015-08-0336.0 ppb
2015-09-14ND
2015-09-290.900 ppb
2015-11-031.000 ppb
2015-11-035.80 ppb
2015-11-037.50 ppb
2015-11-031.60 ppb
2016-02-093.40 ppb
2016-02-092.80 ppb
2016-02-091.90 ppb
2016-02-096.40 ppb
2016-05-043.70 ppb
2016-05-042.10 ppb
2016-05-041.70 ppb
2016-05-043.10 ppb
2016-07-261.50 ppb
2016-08-081.60 ppb
2016-08-0855.0 ppb
2016-08-085.70 ppb
2016-08-0836.0 ppb
2016-08-10ND
2016-08-18ND
2016-08-25ND
2016-08-25ND
2016-09-131.70 ppb
2016-09-290.560 ppb
2016-11-082.80 ppb
2016-11-084.40 ppb
2016-11-088.50 ppb
2016-11-081.10 ppb
2017-02-071.70 ppb
2017-02-072.70 ppb
2017-02-079.20 ppb
2017-02-070.940 ppb
2017-07-031.39 ppb
2017-07-31ND
2017-08-14ND
2017-08-25ND
2017-08-281.86 ppb
2017-09-18ND
2018-02-061.20 ppb
2018-02-061.30 ppb
2018-02-061.000 ppb
2018-02-061.000 ppb
2018-05-081.20 ppb
2018-05-084.90 ppb
2018-05-081.10 ppb
2018-05-083.00 ppb
2018-07-11ND
2018-07-16ND
2018-07-25ND
2018-07-261.04 ppb
2018-07-26ND
2018-08-062.10 ppb
2018-08-0661.0 ppb
2018-08-063.50 ppb
2018-08-0637.0 ppb
2018-08-28ND
2018-08-280.980 ppb
2018-11-061.50 ppb
2018-11-063.50 ppb
2018-11-061.80 ppb
2018-11-063.70 ppb
2019-02-051.20 ppb
2019-02-054.20 ppb
2019-02-055.80 ppb
2019-02-054.50 ppb
2019-05-071.57 ppb
2019-05-074.79 ppb
2019-05-078.05 ppb
2019-05-074.98 ppb
2019-07-01ND
2019-07-01ND
2019-07-03ND
2019-07-111.63 ppb
2019-07-262.95 ppb
2019-07-31ND
2019-09-041.89 ppb
2019-09-0454.9 ppb
2019-09-042.21 ppb
2019-09-0436.7 ppb
2019-09-18ND
2019-11-053.68 ppb
2019-11-059.43 ppb
2019-11-059.56 ppb
2019-11-056.02 ppb