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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Pittsburg

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)

52

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20140.466 ppb169ND - 1.40 ppb
20150.550 ppb1611ND - 1.40 ppb
20160.656 ppb1612ND - 1.40 ppb
20170.694 ppb1612ND - 3.00 ppb
20180.258 ppb166ND - 0.780 ppb
20190.0700 ppb162ND - 0.600 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
2014-02-18640500.930 ppb
2014-02-1864048ND
2014-02-1864046ND
2014-02-1864044ND
2014-05-05110651ND
2014-05-05110650ND
2014-05-051106490.730 ppb
2014-05-05110648ND
2014-08-181759590.920 ppb
2014-08-181759580.670 ppb
2014-08-181759601.40 ppb
2014-08-181759610.540 ppb
2014-11-172329631.000 ppb
2014-11-17232962ND
2014-11-172329610.740 ppb
2014-11-172329590.520 ppb
2015-02-16280167ND
2015-02-16280166ND
2015-02-16280165ND
2015-02-16280164ND
2015-05-183356781.20 ppb
2015-05-183356790.560 ppb
2015-05-183356811.40 ppb
2015-05-183356801.20 ppb
2015-08-173895860.580 ppb
2015-08-173895850.510 ppb
2015-08-173895840.560 ppb
2015-08-173895830.890 ppb
2015-11-30428169ND
2015-11-304281680.660 ppb
2015-11-304281670.730 ppb
2015-11-304281660.510 ppb
2016-02-08490888ND
2016-02-08490887ND
2016-02-08490889ND
2016-02-08490890ND
2016-05-315548800.660 ppb
2016-05-315548790.630 ppb
2016-05-315548780.650 ppb
2016-05-315548770.770 ppb
2016-08-226086960.750 ppb
2016-08-226086951.20 ppb
2016-08-226086941.20 ppb
2016-08-226086930.830 ppb
2016-11-146607420.500 ppb
2016-11-146607451.40 ppb
2016-11-146607440.510 ppb
2016-11-146607431.40 ppb
2017-02-207118193.00 ppb
2017-02-207118180.640 ppb
2017-02-20711817ND
2017-02-207118160.730 ppb
2017-05-30769043ND
2017-05-307690420.710 ppb
2017-05-307690410.500 ppb
2017-05-307690400.890 ppb
2017-08-228248890.540 ppb
2017-08-228248881.50 ppb
2017-08-228248900.720 ppb
2017-08-228248910.730 ppb
2017-11-14878982ND
2017-11-148789810.540 ppb
2017-11-14878980ND
2017-11-148789790.610 ppb
2018-02-20908563ND
2018-02-20908562ND
2018-02-209085610.570 ppb
2018-02-20908560ND
2018-05-229747880.720 ppb
2018-05-229747890.690 ppb
2018-05-22974791ND
2018-05-22974790ND
2018-08-211030105ND
2018-08-211030104ND
2018-08-2110301030.780 ppb
2018-08-211030102ND
2018-11-0610746050.690 ppb
2018-11-0610746040.680 ppb
2018-11-061074603ND
2018-11-061074602ND
2019-02-121121020ND
2019-02-121121019ND
2019-02-121121021ND
2019-02-121121022ND
2019-05-141157997ND
2019-05-141157996ND
2019-05-141157995ND
2019-05-1411579940.520 ppb
2019-08-131223579ND
2019-08-1312235780.600 ppb
2019-08-131223577ND
2019-08-131223576ND
2019-11-181277556ND
2019-11-181277559ND
2019-11-181277558ND
2019-11-181277557ND