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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Harwich 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

 

120

Samples

0

Samples exceeding legal limit (MCL)

101

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.881 ppb1410ND - 2.10 ppb
20150.933 ppb1811ND - 4.20 ppb
20161.03 ppb1814ND - 2.50 ppb
20171.22 ppb2624ND - 2.80 ppb
20181.51 ppb2524ND - 4.20 ppb
20191.25 ppb1918ND - 2.20 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
2014-02-271.80 ppb
2014-02-272.10 ppb
2014-02-27ND
2014-02-270.810 ppb
2014-02-270.970 ppb
2014-02-271.80 ppb
2014-03-051.70 ppb
2014-03-06ND
2014-03-06ND
2014-03-060.660 ppb
2014-03-06ND
2014-03-060.930 ppb
2014-03-060.830 ppb
2014-03-060.730 ppb
2015-02-251.80 ppb
2015-02-251.90 ppb
2015-02-25ND
2015-02-250.660 ppb
2015-02-251.20 ppb
2015-02-251.20 ppb
2015-02-26ND
2015-02-26ND
2015-02-26ND
2015-02-26ND
2015-02-260.740 ppb
2015-02-26ND
2015-02-260.840 ppb
2015-03-134.20 ppb
2015-08-12ND
2015-08-121.70 ppb
2015-08-120.960 ppb
2015-08-121.60 ppb
2016-02-291.60 ppb
2016-02-292.50 ppb
2016-02-291.50 ppb
2016-02-292.10 ppb
2016-02-291.70 ppb
2016-03-02ND
2016-03-02ND
2016-03-020.620 ppb
2016-03-020.620 ppb
2016-03-021.10 ppb
2016-03-021.000 ppb
2016-03-020.740 ppb
2016-03-23ND
2016-03-23ND
2016-08-240.540 ppb
2016-08-242.00 ppb
2016-08-240.900 ppb
2016-08-241.60 ppb
2017-02-28ND
2017-02-281.90 ppb
2017-03-090.620 ppb
2017-03-090.600 ppb
2017-03-092.20 ppb
2017-03-092.80 ppb
2017-03-090.550 ppb
2017-03-090.850 ppb
2017-03-090.520 ppb
2017-03-091.10 ppb
2017-03-091.000 ppb
2017-03-091.70 ppb
2017-03-091.10 ppb
2017-03-091.20 ppb
2017-05-17ND
2017-05-172.00 ppb
2017-06-071.40 ppb
2017-08-090.720 ppb
2017-08-091.10 ppb
2017-08-100.870 ppb
2017-08-102.10 ppb
2017-08-100.880 ppb
2017-08-102.20 ppb
2017-12-202.00 ppb
2017-12-210.590 ppb
2017-12-211.70 ppb
2018-03-080.910 ppb
2018-03-082.40 ppb
2018-03-080.630 ppb
2018-03-080.590 ppb
2018-03-080.740 ppb
2018-03-083.00 ppb
2018-03-08ND
2018-03-080.900 ppb
2018-03-081.50 ppb
2018-03-081.20 ppb
2018-03-080.620 ppb
2018-03-081.30 ppb
2018-05-163.10 ppb
2018-05-163.10 ppb
2018-05-164.20 ppb
2018-08-140.900 ppb
2018-08-141.10 ppb
2018-08-152.60 ppb
2018-08-152.00 ppb
2018-08-151.000 ppb
2018-08-151.20 ppb
2018-08-221.80 ppb
2018-12-100.680 ppb
2018-12-101.20 ppb
2018-12-101.20 ppb
2019-03-060.910 ppb
2019-03-060.780 ppb
2019-03-061.40 ppb
2019-03-061.10 ppb
2019-03-072.20 ppb
2019-03-07ND
2019-06-191.000 ppb
2019-06-191.40 ppb
2019-06-191.20 ppb
2019-08-150.780 ppb
2019-08-151.40 ppb
2019-08-151.30 ppb
2019-08-190.860 ppb
2019-08-191.40 ppb
2019-08-261.70 ppb
2019-08-261.80 ppb
2019-12-040.890 ppb
2019-12-041.80 ppb
2019-12-041.80 ppb