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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Pleasant Valley 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

 

68

Samples

0

Samples exceeding legal limit (MCL)

48

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
20151.84 ppb86ND - 3.24 ppb
20160.620 ppb1210ND - 1.01 ppb
20170.678 ppb168ND - 1.80 ppb
20180.471 ppb1610ND - 1.10 ppb
20191.28 ppb1614ND - 2.50 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 Lab ID Result
2015-08-25LA10772-22.00 ppb
2015-08-25LA10772-12.10 ppb
2015-08-25LA10772-22.00 ppb
2015-08-25LA10772-12.10 ppb
2015-11-2314463523.24 ppb
2015-11-231446356ND
2015-11-231446356ND
2015-11-2314463523.24 ppb
2016-02-0914663171.01 ppb
2016-02-091466318ND
2016-02-091466318ND
2016-02-0914663171.01 ppb
2016-05-1214910700.600 ppb
2016-05-1214910710.590 ppb
2016-05-1214910710.590 ppb
2016-05-1214910700.600 ppb
2016-08-1615164200.920 ppb
2016-08-1615164210.600 ppb
2016-08-1615164210.600 ppb
2016-08-1615164200.920 ppb
2017-02-0335292971009ND
2017-02-0335292971010ND
2017-02-0335292971010ND
2017-02-0335292971009ND
2017-05-04353113080131.80 ppb
2017-05-04353113080120.820 ppb
2017-05-04353113080131.80 ppb
2017-05-04353113080120.820 ppb
2017-08-04353283620261.70 ppb
2017-08-04353283620251.10 ppb
2017-08-04353283620251.10 ppb
2017-08-04353283620261.70 ppb
2017-11-0735347184002ND
2017-11-0735347184001ND
2017-11-0735347184001ND
2017-11-0735347184002ND
2018-02-08353739910010.560 ppb
2018-02-08353739910020.620 ppb
2018-02-08353739910010.560 ppb
2018-02-08353739910020.620 ppb
2018-05-03353903070010.690 ppb
2018-05-03353903070021.10 ppb
2018-05-03353903070010.690 ppb
2018-05-03353903070021.10 ppb
2018-08-0135408823001ND
2018-08-01354088230020.800 ppb
2018-08-0135408823001ND
2018-08-01354088230020.800 ppb
2018-11-0135428181001ND
2018-11-0135428181002ND
2018-11-0135428181001ND
2018-11-0135428181002ND
2019-02-06354470520021.30 ppb
2019-02-06354470520011.10 ppb
2019-02-06354470520011.10 ppb
2019-02-06354470520021.30 ppb
2019-05-01354657730021.40 ppb
2019-05-01354657730021.40 ppb
2019-05-01354657730011.30 ppb
2019-05-01354657730011.30 ppb
2019-08-05354879080021.000 ppb
2019-08-05354879080012.50 ppb
2019-08-05354879080012.50 ppb
2019-08-05354879080021.000 ppb
2019-11-2135514616001ND
2019-11-21355146160021.60 ppb
2019-11-2135514616001ND
2019-11-21355146160021.60 ppb