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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Hyannis Water System

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

 

132

Samples

0

Samples exceeding legal limit (MCL)

75

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
20141.11 ppb105ND - 5.00 ppb
20150.619 ppb268ND - 4.80 ppb
20160.697 ppb3016ND - 2.00 ppb
20171.02 ppb2314ND - 2.40 ppb
20181.09 ppb2213ND - 3.10 ppb
20192.28 ppb2119ND - 4.50 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
2014-02-11ND
2014-04-08ND
2014-07-151.000 ppb
2014-07-151.70 ppb
2014-07-151.70 ppb
2014-07-151.70 ppb
2014-07-155.00 ppb
2014-07-15ND
2014-07-15ND
2014-10-15ND
2015-01-13ND
2015-02-10ND
2015-02-10ND
2015-02-10ND
2015-02-100.700 ppb
2015-04-21ND
2015-05-12ND
2015-05-12ND
2015-05-12ND
2015-05-122.80 ppb
2015-07-142.20 ppb
2015-07-141.70 ppb
2015-07-141.40 ppb
2015-07-141.30 ppb
2015-07-144.80 ppb
2015-07-14ND
2015-07-14ND
2015-08-11ND
2015-08-11ND
2015-08-11ND
2015-08-11ND
2015-11-03ND
2015-11-10ND
2015-11-101.20 ppb
2015-11-10ND
2015-11-10ND
2016-01-14ND
2016-02-091.40 ppb
2016-02-09ND
2016-02-091.60 ppb
2016-02-091.50 ppb
2016-04-13ND
2016-05-10ND
2016-05-10ND
2016-05-10ND
2016-05-10ND
2016-06-080.940 ppb
2016-06-081.000 ppb
2016-06-29ND
2016-07-19ND
2016-07-19ND
2016-07-19ND
2016-07-191.60 ppb
2016-07-19ND
2016-07-191.30 ppb
2016-07-190.960 ppb
2016-07-190.810 ppb
2016-08-10ND
2016-08-101.30 ppb
2016-08-10ND
2016-08-101.40 ppb
2016-10-111.40 ppb
2016-11-231.000 ppb
2016-11-232.00 ppb
2016-11-231.40 ppb
2016-11-231.30 ppb
2017-01-191.40 ppb
2017-02-02ND
2017-02-021.80 ppb
2017-02-02ND
2017-02-021.80 ppb
2017-04-191.90 ppb
2017-04-191.90 ppb
2017-05-09ND
2017-05-092.30 ppb
2017-05-09ND
2017-05-09ND
2017-07-12ND
2017-07-120.510 ppb
2017-07-121.90 ppb
2017-08-08ND
2017-08-081.50 ppb
2017-08-081.60 ppb
2017-08-081.30 ppb
2017-10-181.50 ppb
2017-11-14ND
2017-11-142.40 ppb
2017-11-14ND
2017-11-141.60 ppb
2018-01-092.60 ppb
2018-02-13ND
2018-02-13ND
2018-02-13ND
2018-02-13ND
2018-05-032.30 ppb
2018-05-151.000 ppb
2018-05-152.00 ppb
2018-05-15ND
2018-05-15ND
2018-07-17ND
2018-07-170.520 ppb
2018-07-171.80 ppb
2018-08-07ND
2018-08-072.00 ppb
2018-08-073.10 ppb
2018-08-071.30 ppb
2018-10-231.80 ppb
2018-11-132.40 ppb
2018-11-132.10 ppb
2018-11-131.000 ppb
2018-11-13ND
2019-01-091.80 ppb
2019-02-06ND
2019-02-062.20 ppb
2019-02-06ND
2019-02-061.20 ppb
2019-04-111.80 ppb
2019-05-081.50 ppb
2019-05-082.20 ppb
2019-08-094.50 ppb
2019-08-093.10 ppb
2019-08-094.30 ppb
2019-08-091.90 ppb
2019-08-090.700 ppb
2019-08-092.70 ppb
2019-08-093.00 ppb
2019-10-084.30 ppb
2019-10-082.40 ppb
2019-11-073.90 ppb
2019-11-073.90 ppb
2019-11-071.50 ppb
2019-11-070.980 ppb