Chloroform
North Wales Water Authority
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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 15.6 ppb | 37 | 37 | 1.91 ppb - 41.4 ppb |
2015 | 15.3 ppb | 27 | 27 | 1.43 ppb - 34.3 ppb |
2016 | 13.9 ppb | 39 | 39 | 3.03 ppb - 33.1 ppb |
2017 | 22.0 ppb | 80 | 80 | 2.84 ppb - 39.4 ppb |
2018 | 23.4 ppb | 62 | 62 | 2.52 ppb - 52.5 ppb |
2019 | 20.9 ppb | 54 | 54 | 2.39 ppb - 55.4 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 |
---|---|---|
2014-02-12 | 20140557 | 10.8 ppb |
2014-02-12 | 20140558 | 14.4 ppb |
2014-02-12 | 20140559 | 8.15 ppb |
2014-02-12 | 20140560 | 7.29 ppb |
2014-02-12 | 20140561 | 3.94 ppb |
2014-02-12 | 20140562 | 11.4 ppb |
2014-02-12 | 20140563 | 9.20 ppb |
2014-02-12 | 20140564 | 4.83 ppb |
2014-02-17 | 20140576 | 8.34 ppb |
2014-02-17 | 20140577 | 9.82 ppb |
2014-03-04 | 20140745 | 1.91 ppb |
2014-05-13 | 20141613 | 21.7 ppb |
2014-05-13 | 20141614 | 28.8 ppb |
2014-05-13 | 20141615 | 18.1 ppb |
2014-05-13 | 20141616 | 20.3 ppb |
2014-05-13 | 20141617 | 20.5 ppb |
2014-05-13 | 20141618 | 24.8 ppb |
2014-05-13 | 20141619 | 23.5 ppb |
2014-05-13 | 20141620 | 17.2 ppb |
2014-06-10 | 20141963 | 4.78 ppb |
2014-08-05 | 20142640 | 4.94 ppb |
2014-08-12 | 20142741 | 30.2 ppb |
2014-08-12 | 20142742 | 41.4 ppb |
2014-08-12 | 20142743 | 21.0 ppb |
2014-08-12 | 20142744 | 21.5 ppb |
2014-08-12 | 20142745 | 29.3 ppb |
2014-08-12 | 20142746 | 18.6 ppb |
2014-08-12 | 20142747 | 14.8 ppb |
2014-08-12 | 20142748 | 6.13 ppb |
2014-11-11 | 14111187-01 | 14.0 ppb |
2014-11-11 | 14111187-02 | 26.8 ppb |
2014-11-11 | 14111187-03 | 14.2 ppb |
2014-11-11 | 14111187-04 | 12.8 ppb |
2014-11-11 | 14111187-05 | 20.4 ppb |
2014-11-11 | 14111187-06 | 15.6 ppb |
2014-11-11 | 14111187-07 | 14.0 ppb |
2014-11-11 | 14111187-08 | 3.50 ppb |
2015-02-10 | 12403028 | 11.3 ppb |
2015-02-10 | 12403033 | 17.0 ppb |
2015-02-10 | 12403038 | 9.18 ppb |
2015-02-10 | 12403043 | 8.61 ppb |
2015-02-10 | 12403048 | 9.34 ppb |
2015-02-10 | 12403053 | 8.18 ppb |
2015-02-10 | 12403058 | 8.08 ppb |
2015-02-10 | 12403063 | 4.68 ppb |
2015-03-10 | 12516878 | 1.43 ppb |
2015-08-11 | 13136890 | 27.4 ppb |
2015-08-11 | 13136895 | 34.3 ppb |
2015-08-11 | 13136900 | 21.9 ppb |
2015-08-11 | 13136905 | 24.5 ppb |
2015-08-11 | 13136910 | 32.3 ppb |
2015-08-11 | 13136915 | 18.3 ppb |
2015-08-11 | 13136920 | 24.1 ppb |
2015-08-11 | 13136925 | 5.69 ppb |
2015-09-14 | 13265900 | 3.33 ppb |
2015-11-11 | 13515288 | 18.0 ppb |
2015-11-11 | 13515293 | 27.3 ppb |
2015-11-11 | 13515298 | 17.2 ppb |
2015-11-11 | 13515303 | 16.4 ppb |
2015-11-11 | 13515308 | 17.2 ppb |
2015-11-11 | 13515313 | 16.4 ppb |
2015-11-11 | 13515318 | 16.2 ppb |
2015-11-11 | 13515323 | 11.3 ppb |
2015-12-01 | 13634683 | 2.26 ppb |
2016-02-10 | 13871418 | 7.89 ppb |
2016-02-10 | 13871423 | 17.3 ppb |
2016-02-10 | 13871428 | 8.17 ppb |
2016-02-10 | 13871433 | 7.21 ppb |
2016-02-10 | 13871438 | 17.7 ppb |
2016-02-10 | 13871443 | 9.14 ppb |
2016-02-10 | 13871448 | 14.0 ppb |
2016-02-10 | 13871453 | 4.87 ppb |
2016-03-07 | 13987510 | 4.10 ppb |
2016-05-11 | 14252421 | 8.40 ppb |
2016-05-11 | 14252427 | 14.8 ppb |
2016-05-11 | 14252433 | 12.0 ppb |
2016-05-11 | 14252439 | 8.60 ppb |
2016-05-11 | 14252445 | 16.4 ppb |
2016-05-11 | 14252451 | 9.30 ppb |
2016-05-11 | 14252457 | 19.0 ppb |
2016-05-11 | 14252463 | 3.80 ppb |
2016-06-07 | 14407391 | 3.03 ppb |
2016-06-07 | 14407392 | 3.03 ppb |
2016-06-29 | 14407418 | 4.01 ppb |
2016-06-29 | 14407419 | 4.01 ppb |
2016-08-10 | 14737310 | 28.2 ppb |
2016-08-10 | 14737316 | 26.3 ppb |
2016-08-10 | 14737322 | 25.6 ppb |
2016-08-10 | 14737328 | 20.8 ppb |
2016-08-10 | 14737334 | 28.7 ppb |
2016-08-10 | 14737340 | 14.6 ppb |
2016-08-10 | 14737346 | 23.6 ppb |
2016-08-10 | 14737352 | 6.00 ppb |
2016-09-06 | 14909867 | 5.25 ppb |
2016-09-06 | 14909868 | 5.25 ppb |
2016-11-09 | 15227770 | 23.9 ppb |
2016-11-09 | 15227776 | 31.4 ppb |
2016-11-09 | 15227782 | 18.7 ppb |
2016-11-09 | 15227788 | 10.7 ppb |
2016-11-09 | 15227794 | 17.8 ppb |
2016-11-09 | 15227800 | 15.9 ppb |
2016-11-09 | 15227806 | 33.1 ppb |
2016-11-09 | 15227812 | 8.00 ppb |
2017-02-08 | 15657191 | 13.3 ppb |
2017-02-08 | 15657192 | 13.3 ppb |
2017-02-08 | 15657197 | 17.8 ppb |
2017-02-08 | 15657198 | 17.8 ppb |
2017-02-08 | 15657203 | 15.0 ppb |
2017-02-08 | 15657204 | 15.0 ppb |
2017-02-08 | 15657209 | 10.1 ppb |
2017-02-08 | 15657210 | 10.1 ppb |
2017-02-08 | 15657215 | 13.4 ppb |
2017-02-08 | 15657216 | 13.4 ppb |
2017-02-08 | 15657221 | 20.0 ppb |
2017-02-08 | 15657222 | 20.0 ppb |
2017-02-08 | 15657227 | 18.9 ppb |
2017-02-08 | 15657228 | 18.9 ppb |
2017-02-08 | 15657233 | 8.48 ppb |
2017-02-08 | 15657234 | 8.48 ppb |
2017-03-16 | 15797878 | 2.84 ppb |
2017-03-16 | 15797879 | 2.84 ppb |
2017-05-10 | 16096468 | 36.5 ppb |
2017-05-10 | 16096469 | 36.5 ppb |
2017-05-10 | 16096474 | 19.2 ppb |
2017-05-10 | 16096475 | 19.2 ppb |
2017-05-10 | 16096480 | 14.2 ppb |
2017-05-10 | 16096481 | 14.2 ppb |
2017-05-10 | 16096486 | 23.4 ppb |
2017-05-10 | 16096487 | 23.4 ppb |
2017-05-10 | 16096492 | 24.6 ppb |
2017-05-10 | 16096493 | 24.6 ppb |
2017-05-10 | 16096498 | 37.7 ppb |
2017-05-10 | 16096499 | 37.7 ppb |
2017-05-10 | 16096504 | 34.0 ppb |
2017-05-10 | 16096505 | 34.0 ppb |
2017-05-10 | 16096510 | 8.91 ppb |
2017-05-10 | 16096511 | 8.91 ppb |
2017-06-06 | 16259069 | 5.99 ppb |
2017-06-06 | 16259070 | 5.99 ppb |
2017-08-09 | 16568087 | 35.5 ppb |
2017-08-09 | 16568088 | 35.5 ppb |
2017-08-09 | 16567863 | 28.0 ppb |
2017-08-09 | 16568093 | 33.6 ppb |
2017-08-09 | 16568094 | 33.6 ppb |
2017-08-09 | 16567868 | 25.2 ppb |
2017-08-09 | 16568099 | 38.1 ppb |
2017-08-09 | 16568100 | 38.1 ppb |
2017-08-09 | 16567873 | 28.9 ppb |
2017-08-09 | 16568105 | 23.0 ppb |
2017-08-09 | 16568106 | 23.0 ppb |
2017-08-09 | 16567878 | 17.3 ppb |
2017-08-09 | 16568111 | 39.4 ppb |
2017-08-09 | 16568112 | 39.4 ppb |
2017-08-09 | 16567883 | 31.4 ppb |
2017-08-09 | 16568117 | 37.4 ppb |
2017-08-09 | 16568118 | 37.4 ppb |
2017-08-09 | 16567888 | 28.1 ppb |
2017-08-09 | 16568123 | 39.3 ppb |
2017-08-09 | 16568124 | 39.3 ppb |
2017-08-09 | 16567893 | 29.8 ppb |
2017-08-09 | 16568129 | 7.47 ppb |
2017-08-09 | 16568130 | 7.47 ppb |
2017-08-09 | 16567898 | 5.50 ppb |
2017-09-05 | 16728669 | 4.62 ppb |
2017-09-05 | 16728670 | 4.62 ppb |
2017-11-13 | 17024973 | 31.6 ppb |
2017-11-13 | 17024974 | 31.6 ppb |
2017-11-13 | 17024979 | 26.9 ppb |
2017-11-13 | 17024980 | 26.9 ppb |
2017-11-13 | 17024985 | 24.1 ppb |
2017-11-13 | 17024986 | 24.1 ppb |
2017-11-13 | 17024991 | 16.6 ppb |
2017-11-13 | 17024992 | 16.6 ppb |
2017-11-13 | 17024997 | 28.1 ppb |
2017-11-13 | 17024998 | 28.1 ppb |
2017-11-13 | 17025003 | 35.1 ppb |
2017-11-13 | 17025004 | 35.1 ppb |
2017-11-13 | 17025009 | 27.2 ppb |
2017-11-13 | 17025010 | 27.2 ppb |
2017-11-13 | 17025015 | 7.16 ppb |
2017-11-13 | 17025016 | 7.16 ppb |
2017-12-05 | 17163831 | 3.68 ppb |
2017-12-05 | 17163832 | 3.68 ppb |
2018-02-12 | 20180597 | 19.0 ppb |
2018-02-12 | 20180597 | 19.0 ppb |
2018-02-12 | 20180598 | 15.7 ppb |
2018-02-12 | 20180598 | 15.7 ppb |
2018-02-12 | 20180599 | 12.7 ppb |
2018-02-12 | 20180599 | 12.7 ppb |
2018-02-12 | 20180600 | 8.75 ppb |
2018-02-12 | 20180600 | 8.75 ppb |
2018-02-12 | 20180601 | 11.6 ppb |
2018-02-12 | 20180601 | 11.6 ppb |
2018-02-12 | 20180602 | 23.6 ppb |
2018-02-12 | 20180602 | 23.6 ppb |
2018-02-12 | 20180603 | 14.5 ppb |
2018-02-12 | 20180603 | 14.5 ppb |
2018-02-12 | 20180604 | 5.35 ppb |
2018-02-12 | 20180604 | 5.35 ppb |
2018-03-13 | 20180956 | 2.52 ppb |
2018-03-13 | 20180956 | 2.52 ppb |
2018-05-14 | 20181890 | 27.7 ppb |
2018-05-14 | 20181890 | 27.7 ppb |
2018-05-14 | 20181891 | 18.2 ppb |
2018-05-14 | 20181891 | 18.2 ppb |
2018-05-14 | 20181892 | 24.0 ppb |
2018-05-14 | 20181892 | 24.0 ppb |
2018-05-14 | 20181893 | 14.3 ppb |
2018-05-14 | 20181893 | 14.3 ppb |
2018-05-14 | 20181894 | 18.9 ppb |
2018-05-14 | 20181894 | 18.9 ppb |
2018-05-14 | 20181895 | 28.8 ppb |
2018-05-14 | 20181895 | 28.8 ppb |
2018-05-14 | 20181896 | 26.9 ppb |
2018-05-14 | 20181896 | 26.9 ppb |
2018-05-14 | 20181897 | 7.93 ppb |
2018-05-14 | 20181897 | 7.93 ppb |
2018-06-05 | 20182148 | 4.50 ppb |
2018-06-05 | 20182148 | 4.50 ppb |
2018-08-13 | 20183097 | 38.2 ppb |
2018-08-13 | 20183097 | 38.2 ppb |
2018-08-13 | 20183098 | 36.3 ppb |
2018-08-13 | 20183098 | 36.3 ppb |
2018-08-13 | 20183099 | 44.8 ppb |
2018-08-13 | 20183099 | 44.8 ppb |
2018-08-13 | 20183100 | 28.8 ppb |
2018-08-13 | 20183100 | 28.8 ppb |
2018-08-13 | 20183101 | 41.4 ppb |
2018-08-13 | 20183101 | 41.4 ppb |
2018-08-13 | 20183102 | 24.1 ppb |
2018-08-13 | 20183102 | 24.1 ppb |
2018-08-13 | 20183103 | 37.4 ppb |
2018-08-13 | 20183103 | 37.4 ppb |
2018-08-13 | 20183104 | 14.4 ppb |
2018-08-13 | 20183104 | 14.4 ppb |
2018-09-04 | 20183373 | 8.01 ppb |
2018-09-04 | 20183373 | 8.01 ppb |
2018-11-12 | 8113026-01 | 52.5 ppb |
2018-11-12 | 8113026-02 | 45.8 ppb |
2018-11-12 | 8113026-03 | 44.1 ppb |
2018-11-12 | 8113026-04 | 30.8 ppb |
2018-11-12 | 8113026-05 | 49.4 ppb |
2018-11-12 | 8113026-06 | 48.6 ppb |
2018-11-12 | 8113026-07 | 49.0 ppb |
2018-11-12 | 8113026-08 | 13.2 ppb |
2019-02-11 | 20190552 | 13.7 ppb |
2019-02-11 | 20190552 | 13.7 ppb |
2019-02-11 | 20190553 | 20.6 ppb |
2019-02-11 | 20190553 | 20.6 ppb |
2019-02-11 | 20190554 | 16.9 ppb |
2019-02-11 | 20190554 | 16.9 ppb |
2019-02-11 | 20190555 | 9.79 ppb |
2019-02-11 | 20190555 | 9.79 ppb |
2019-02-11 | 20190556 | 10.4 ppb |
2019-02-11 | 20190556 | 10.4 ppb |
2019-02-11 | 20190557 | 24.3 ppb |
2019-02-11 | 20190557 | 24.3 ppb |
2019-02-11 | 20190558 | 23.0 ppb |
2019-02-11 | 20190558 | 23.0 ppb |
2019-02-11 | 20190559 | 5.81 ppb |
2019-02-11 | 20190559 | 5.81 ppb |
2019-03-05 | 20190857 | 2.85 ppb |
2019-03-05 | 20190857 | 2.85 ppb |
2019-05-13 | 20191796 | 25.3 ppb |
2019-05-13 | 20191796 | 25.3 ppb |
2019-05-13 | 20191797 | 34.1 ppb |
2019-05-13 | 20191797 | 34.1 ppb |
2019-05-13 | 20191798 | 24.6 ppb |
2019-05-13 | 20191798 | 24.6 ppb |
2019-05-13 | 20191799 | 13.3 ppb |
2019-05-13 | 20191799 | 13.3 ppb |
2019-05-13 | 20191800 | 23.6 ppb |
2019-05-13 | 20191800 | 23.6 ppb |
2019-05-13 | 20191801 | 32.5 ppb |
2019-05-13 | 20191801 | 32.5 ppb |
2019-05-13 | 20191802 | 24.2 ppb |
2019-05-13 | 20191802 | 24.2 ppb |
2019-05-13 | 20191803 | 6.93 ppb |
2019-05-13 | 20191803 | 6.93 ppb |
2019-08-13 | 9083732-01 | 47.4 ppb |
2019-08-13 | 9083732-02 | 43.8 ppb |
2019-08-13 | 9083732-03 | 37.0 ppb |
2019-08-13 | 9083732-04 | 31.2 ppb |
2019-08-13 | 9083732-05 | 43.3 ppb |
2019-08-13 | 9083732-06 | 22.8 ppb |
2019-08-13 | 9083732-07RE | 55.4 ppb |
2019-08-13 | 9083732-08 | 12.0 ppb |
2019-09-03 | 20193443 | 3.45 ppb |
2019-09-03 | 20193443 | 3.45 ppb |
2019-11-11 | 9113440-01 | 18.3 ppb |
2019-11-11 | 20194418 | 28.9 ppb |
2019-11-11 | 20194419 | 31.1 ppb |
2019-11-11 | 20194420 | 24.5 ppb |
2019-11-11 | 20194422 | 16.5 ppb |
2019-11-11 | 20194423 | 26.6 ppb |
2019-11-11 | 20194424 | 33.9 ppb |
2019-11-11 | 20194425 | 5.84 ppb |
2019-12-03 | 9121679-01 | 15.6 ppb |
2019-12-03 | 20194748 | 2.39 ppb |