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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

Central Wy Reg Water Sys Jpb

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

 

178

Samples

0

Samples exceeding legal limit (MCL)

172

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20142.49 ppb2928ND - 5.40 ppb
20153.14 ppb3736ND - 6.60 ppb
20164.08 ppb3736ND - 9.10 ppb
20174.23 ppb3836ND - 8.90 ppb
20183.79 ppb3736ND - 12.0 ppb
2019N/A00N/A

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
2014-04-08C14040258-004A3.80 ppb
2014-04-08C14040258-005A3.91 ppb
2014-04-08C14040258-006A3.90 ppb
2014-04-08C14040258-007A3.12 ppb
2014-04-08C14040258-009A2.80 ppb
2014-04-08C14040258-011A3.35 ppb
2014-04-08C14040258-001A3.66 ppb
2014-04-08C14040258-002A2.22 ppb
2014-04-08C14040258-003A5.20 ppb
2014-06-25C14060882-001LND
2014-06-25C14060882-002L1.54 ppb
2014-07-08C14070272-001A0.670 ppb
2014-07-08C14070272-002A0.660 ppb
2014-07-08C14070272-003A0.720 ppb
2014-07-08C14070272-004A0.640 ppb
2014-07-08C14070272-005A0.500 ppb
2014-07-08C14070272-006A0.500 ppb
2014-07-08C14070272-007A0.550 ppb
2014-07-08C14070272-009A0.560 ppb
2014-07-08C14070272-011A0.610 ppb
2014-10-07C14100434-001A4.40 ppb
2014-10-07C14100434-002A2.00 ppb
2014-10-07C14100434-003A2.50 ppb
2014-10-07C14100434-004A5.40 ppb
2014-10-07C14100434-005A4.70 ppb
2014-10-07C14100434-006A4.20 ppb
2014-10-07C14100434-007A4.00 ppb
2014-10-07C14100434-009A4.10 ppb
2014-10-07C14100434-011A1.90 ppb
2015-01-06C15010069-001A4.40 ppb
2015-01-06C15010069-002A2.50 ppb
2015-01-06C15010069-003A4.60 ppb
2015-01-06C15010069-004A4.00 ppb
2015-01-06C15010069-005A3.60 ppb
2015-01-06C15010069-006A3.90 ppb
2015-01-06C15010069-007A3.20 ppb
2015-01-06C15010069-009A3.40 ppb
2015-01-06C15010069-011A4.40 ppb
2015-04-07C15040208-001A3.70 ppb
2015-04-07C15040208-002A3.30 ppb
2015-04-07C15040208-003A4.80 ppb
2015-04-07C15040208-004A5.00 ppb
2015-04-07C15040208-005A4.80 ppb
2015-04-07C15040208-006A4.30 ppb
2015-04-07C15040208-007A4.00 ppb
2015-04-07C15040208-009A4.60 ppb
2015-04-07C15040208-011A4.50 ppb
2015-07-07C15070202-001A2.00 ppb
2015-07-07C15070202-002A1.50 ppb
2015-07-07C15070202-003A2.90 ppb
2015-07-07C15070202-004A3.00 ppb
2015-07-07C15070202-005A4.00 ppb
2015-07-07C15070202-006A1.50 ppb
2015-07-07C15070202-007A1.10 ppb
2015-07-07C15070202-009A1.30 ppb
2015-07-07C15070202-011A1.70 ppb
2015-07-14C15070490-001END
2015-10-06C15100213-001A4.00 ppb
2015-10-06C15100213-002A2.30 ppb
2015-10-06C15100213-003A2.40 ppb
2015-10-06C15100213-004A6.60 ppb
2015-10-06C15100213-005A1.50 ppb
2015-10-06C15100213-006A2.40 ppb
2015-10-06C15100213-007A2.40 ppb
2015-10-06C15100213-009A1.30 ppb
2015-10-06C15100213-011A1.30 ppb
2016-01-05C16010071-001A6.20 ppb
2016-01-05C16010071-002A4.90 ppb
2016-01-05C16010071-003A5.00 ppb
2016-01-05C16010071-004A4.70 ppb
2016-01-05C16010071-005A4.80 ppb
2016-01-05C16010071-006A4.50 ppb
2016-01-05C16010071-007A4.40 ppb
2016-01-05C16010071-009A4.40 ppb
2016-01-05C16010071-011A5.40 ppb
2016-04-05C16040146-001A3.50 ppb
2016-04-05C16040146-002A2.90 ppb
2016-04-05C16040146-003A3.50 ppb
2016-04-05C16040146-004A4.00 ppb
2016-04-05C16040146-005A3.80 ppb
2016-04-05C16040146-006A3.70 ppb
2016-04-05C16040146-007A3.60 ppb
2016-04-05C16040146-009A3.90 ppb
2016-04-05C16040146-011A4.20 ppb
2016-06-06C16060160-001DND
2016-07-05C16070073-001A4.00 ppb
2016-07-05C16070073-002A5.40 ppb
2016-07-05C16070073-003A4.60 ppb
2016-07-05C16070073-004A3.40 ppb
2016-07-05C16070073-005A0.840 ppb
2016-07-05C16070073-006A1.50 ppb
2016-07-05C16070073-007A1.20 ppb
2016-07-05C16070073-009A1.80 ppb
2016-07-05C16070073-011A2.00 ppb
2016-10-05C16100154-001A5.70 ppb
2016-10-05C16100154-002A2.80 ppb
2016-10-05C16100154-003A9.10 ppb
2016-10-05C16100154-004A6.10 ppb
2016-10-05C16100154-005A5.50 ppb
2016-10-05C16100154-006A5.20 ppb
2016-10-05C16100154-007A5.20 ppb
2016-10-05C16100154-009A4.20 ppb
2016-10-05C16100154-011B5.10 ppb
2017-01-04C17010096-001A3.90 ppb
2017-01-04C17010096-002A3.50 ppb
2017-01-04C17010096-003A4.20 ppb
2017-01-04C17010096-004A4.20 ppb
2017-01-04C17010096-005A3.80 ppb
2017-01-04C17010096-006A3.70 ppb
2017-01-04C17010096-007A3.80 ppb
2017-01-04C17010096-009A3.60 ppb
2017-01-04C17010096-011A4.40 ppb
2017-04-04C17040071-001A5.20 ppb
2017-04-04C17040071-002A4.40 ppb
2017-04-04C17040071-003A4.30 ppb
2017-04-04C17040071-004A6.10 ppb
2017-04-04C17040071-005A5.40 ppb
2017-04-04C17040071-006A5.20 ppb
2017-04-04C17040071-007A5.70 ppb
2017-04-04C17040071-009A5.40 ppb
2017-04-04C17040071-011A6.00 ppb
2017-06-13C17060420-001LND
2017-06-13C17060420-002LND
2017-07-05C17070062-001A2.10 ppb
2017-07-05C17070062-002A1.50 ppb
2017-07-05C17070062-003A2.80 ppb
2017-07-05C17070062-004A3.50 ppb
2017-07-05C17070062-005A1.30 ppb
2017-07-05C17070062-006A1.80 ppb
2017-07-05C17070062-007A1.30 ppb
2017-07-05C17070062-009A0.990 ppb
2017-07-05C17070062-011A0.850 ppb
2017-10-03C17100100-001A5.20 ppb
2017-10-03C17100100-002A6.30 ppb
2017-10-03C17100100-003A8.20 ppb
2017-10-03C17100100-004A8.90 ppb
2017-10-03C17100100-005A6.70 ppb
2017-10-03C17100100-006A6.10 ppb
2017-10-03C17100100-007A6.00 ppb
2017-10-03C17100100-009A6.80 ppb
2017-10-03C17100100-011A7.70 ppb
2018-01-09C18010249-002A2.80 ppb
2018-01-09C18010249-003A5.50 ppb
2018-01-09C18010249-004A4.80 ppb
2018-01-09C18010249-005A4.10 ppb
2018-01-09C18010249-006A4.70 ppb
2018-01-09C18010249-007A3.90 ppb
2018-01-09C18010249-009A4.00 ppb
2018-01-09C18010249-011A4.30 ppb
2018-01-09C18010249-001A3.90 ppb
2018-04-03C18040084-009A1.70 ppb
2018-04-03C18040084-007A3.20 ppb
2018-04-03C18040084-006A3.10 ppb
2018-04-03C18040084-005A2.40 ppb
2018-04-03C18040084-011A1.90 ppb
2018-04-03C18040084-003A1.90 ppb
2018-04-03C18040084-002A2.30 ppb
2018-04-03C18040084-001A0.710 ppb
2018-04-03C18040084-004A3.70 ppb
2018-06-27C18060967-001DND
2018-07-03C18070084-011A1.000 ppb
2018-07-03C18070084-009A1.30 ppb
2018-07-03C18070084-007A2.40 ppb
2018-07-03C18070084-006A4.30 ppb
2018-07-03C18070084-005A2.30 ppb
2018-07-03C18070084-004A7.60 ppb
2018-07-03C18070084-003A3.00 ppb
2018-07-03C18070084-001A4.10 ppb
2018-07-03C18070084-002A2.00 ppb
2018-10-10C18100435-001A5.60 ppb
2018-10-10C18100435-002A1.80 ppb
2018-10-10C18100435-003A8.40 ppb
2018-10-10C18100435-004A12.0 ppb
2018-10-10C18100435-011A6.60 ppb
2018-10-10C18100435-006A4.80 ppb
2018-10-10C18100435-007A3.30 ppb
2018-10-10C18100435-009A5.50 ppb
2018-10-10C18100435-005A5.20 ppb