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EWG's Tap Water Database — 2021 UPDATE

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Chloroform

City of Santa Clara

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

 

246

Samples

0

Samples exceeding legal limit (MCL)

161

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
201410.3 ppb3725ND - 40.0 ppb
201510.5 ppb4023ND - 52.0 ppb
201618.0 ppb5033ND - 63.0 ppb
201715.7 ppb3728ND - 44.0 ppb
201813.0 ppb4128ND - 45.0 ppb
201910.5 ppb4124ND - 44.0 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
2014-01-229590-900-104419.0 ppb
2014-01-229590-901-103014.0 ppb
2014-01-229590-902-110519.0 ppb
2014-01-229590-903-1015ND
2014-01-229590-904-0935ND
2014-01-229590-905-08341.20 ppb
2014-01-229590-906-08542.40 ppb
2014-01-229590-907-09551.60 ppb
2014-04-029590-030-1035ND
2014-04-239590-900-102529.0 ppb
2014-04-239590-901-101029.0 ppb
2014-04-239590-902-104030.0 ppb
2014-04-239590-903-09555.40 ppb
2014-04-239590-904-09101.80 ppb
2014-04-239590-905-083512.0 ppb
2014-04-239590-906-08509.00 ppb
2014-04-239590-907-0930ND
2014-07-239590-900-134031.0 ppb
2014-07-239590-901-0905ND
2014-07-239590-902-094532.0 ppb
2014-07-239590-903-0845ND
2014-07-239590-904-1005ND
2014-07-239590-905-1025ND
2014-07-239590-906-10452.90 ppb
2014-07-239590-907-11303.10 ppb
2014-08-269590-027-1050ND
2014-08-269590-034-0930ND
2014-08-279590-011-0905ND
2014-08-279590-036-1030ND
2014-10-249590-900-091034.0 ppb
2014-10-249590-901-093036.0 ppb
2014-10-249590-902-085540.0 ppb
2014-10-249590-903-09157.10 ppb
2014-10-249590-904-10253.70 ppb
2014-10-249590-905-09356.10 ppb
2014-10-249590-906-09555.60 ppb
2014-10-249590-907-10455.40 ppb
2015-01-219590-900-121527.0 ppb
2015-01-219590-901-114231.0 ppb
2015-01-219590-902-112630.0 ppb
2015-01-219590-903-1150ND
2015-01-219590-904-0948ND
2015-01-219590-905-1003ND
2015-01-219590-906-102613.0 ppb
2015-01-219590-907-09266.10 ppb
2015-04-229590-900-094532.0 ppb
2015-04-229590-901-091532.0 ppb
2015-04-229590-902-101032.0 ppb
2015-04-229590-903-0858ND
2015-04-229590-904-11253.60 ppb
2015-04-229590-905-1410ND
2015-04-229590-906-143514.0 ppb
2015-04-229590-907-1140ND
2015-07-239590-900-141032.0 ppb
2015-07-239590-901-11157.30 ppb
2015-07-239590-902-134530.0 ppb
2015-07-239590-903-1050ND
2015-07-239590-904-09503.10 ppb
2015-07-239590-905-08503.00 ppb
2015-07-239590-906-09103.00 ppb
2015-07-239590-907-10151.90 ppb
2015-08-179590-004-0925ND
2015-08-179590-019-1045ND
2015-08-199590-002-0955ND
2015-08-199590-015-1100ND
2015-08-209590-007-1120ND
2015-08-209590-031-1010ND
2015-08-249590-013-0950ND
2015-08-249590-014-1045ND
2015-10-219590-900-132152.0 ppb
2015-10-219590-901-112511.0 ppb
2015-10-219590-902-134051.0 ppb
2015-10-219590-903-1108ND
2015-10-219590-904-10221.90 ppb
2015-10-219590-905-0923ND
2015-10-219590-906-09572.20 ppb
2015-10-219590-907-10412.20 ppb
2016-01-209590-900-100050.0 ppb
2016-01-209590-901-093534.0 ppb
2016-01-209590-902-102048.0 ppb
2016-01-209590-903-09153.80 ppb
2016-01-209590-904-13561.90 ppb
2016-01-209590-905-10453.40 ppb
2016-01-209590-906-11024.30 ppb
2016-01-209590-907-14133.60 ppb
2016-01-279590-900-112763.0 ppb
2016-01-279590-901-110561.0 ppb
2016-01-279590-902-114663.0 ppb
2016-01-279590-903-105054.0 ppb
2016-01-279590-904-1206ND
2016-01-279590-905-1218ND
2016-01-279590-906-12325.20 ppb
2016-01-279590-907-13565.80 ppb
2016-04-209590-900-102140.0 ppb
2016-04-209590-901-100229.0 ppb
2016-04-209590-902-104339.0 ppb
2016-04-209590-903-0942ND
2016-04-209590-904-1159ND
2016-04-209590-905-1106ND
2016-04-209590-906-112913.0 ppb
2016-04-209590-907-122410.00 ppb
2016-07-209590-900-110353.0 ppb
2016-07-209590-901-082752.0 ppb
2016-07-209590-902-085556.0 ppb
2016-07-209590-903-080920.0 ppb
2016-07-209590-904-100710.00 ppb
2016-07-209590-905-092514.0 ppb
2016-07-209590-906-094214.0 ppb
2016-07-209590-907-1022ND
2016-08-159590-010-1055ND
2016-08-159590-016-1010ND
2016-08-159590-018-0915ND
2016-08-179590-005-1127ND
2016-08-179590-025-0918ND
2016-08-179590-029-1016ND
2016-08-189590-008-0956ND
2016-08-189590-012-1035ND
2016-08-189590-023-0920ND
2016-09-289590-026-0855ND
2016-10-269590-900-092747.0 ppb
2016-10-269590-901-091446.0 ppb
2016-10-269590-902-094046.0 ppb
2016-10-269590-903-09011.60 ppb
2016-10-269590-904-10553.00 ppb
2016-10-269590-905-1003ND
2016-10-269590-906-10212.80 ppb
2016-10-269590-907-11082.90 ppb
2017-01-259590-900-112814.0 ppb
2017-01-259590-901-120115.0 ppb
2017-01-259590-902-105417.0 ppb
2017-01-259590-903-114614.0 ppb
2017-01-259590-904-0959ND
2017-01-259590-905-08521.70 ppb
2017-01-259590-906-09153.30 ppb
2017-01-259590-907-10281.90 ppb
2017-04-199590-900-120042.0 ppb
2017-04-199590-901-104843.0 ppb
2017-04-199590-902-121944.0 ppb
2017-04-199590-903-103544.0 ppb
2017-04-199590-904-0952ND
2017-04-199590-905-08381.70 ppb
2017-04-199590-906-09035.30 ppb
2017-04-199590-907-10106.00 ppb
2017-04-249590-030-1120ND
2017-08-029590-900-105337.0 ppb
2017-08-029590-901-103841.0 ppb
2017-08-029590-902-111840.0 ppb
2017-08-029590-903-1025ND
2017-08-029590-904-09386.60 ppb
2017-08-029590-905-08417.50 ppb
2017-08-029590-906-09017.00 ppb
2017-08-029590-907-0953ND
2017-08-169590-011-0901ND
2017-08-169590-027-1012ND
2017-08-179590-036-1055ND
2017-10-049590-034-1007ND
2017-10-189590-900-101435.0 ppb
2017-10-189590-901-092935.0 ppb
2017-10-189590-902-095935.0 ppb
2017-10-189590-903-091429.0 ppb
2017-10-189590-904-114414.0 ppb
2017-10-189590-905-115516.0 ppb
2017-10-189590-906-125315.0 ppb
2017-10-189590-907-12128.90 ppb
2018-01-239590-022-1010ND
2018-01-299590-900-075528.0 ppb
2018-01-299590-901-084327.0 ppb
2018-01-299590-902-081731.0 ppb
2018-01-299590-903-083216.0 ppb
2018-01-299590-904-1008ND
2018-01-299590-905-09091.50 ppb
2018-01-299590-906-09283.90 ppb
2018-01-299590-907-10234.00 ppb
2018-05-239590-900-100445.0 ppb
2018-05-259590-901-094742.0 ppb
2018-05-259590-902-10254.40 ppb
2018-05-259590-903-093939.0 ppb
2018-05-259590-904-06086.60 ppb
2018-05-259590-905-08189.70 ppb
2018-05-259590-906-083510.00 ppb
2018-05-259590-907-0913ND
2018-07-259590-900-090040.0 ppb
2018-07-259590-901-084839.0 ppb
2018-07-259590-902-09152.70 ppb
2018-07-259590-903-083839.0 ppb
2018-07-259590-904-10155.90 ppb
2018-07-259590-905-0939ND
2018-07-259590-906-09546.30 ppb
2018-07-259590-907-10275.30 ppb
2018-08-139590-004-0908ND
2018-08-139590-026-1047ND
2018-08-169590-002-1000ND
2018-08-169590-031-0900ND
2018-08-209590-013-1005ND
2018-08-209590-014-0840ND
2018-08-209590-019-1042ND
2018-09-129590-007-1011ND
2018-10-179590-900-093033.0 ppb
2018-10-179590-901-090433.0 ppb
2018-10-179590-902-094631.0 ppb
2018-10-179590-903-085019.0 ppb
2018-10-179590-904-10073.00 ppb
2018-10-179590-905-10193.30 ppb
2018-10-179590-906-10543.40 ppb
2018-10-179590-907-1117ND
2019-01-169590-900-095711.0 ppb
2019-01-169590-901-093410.00 ppb
2019-01-169590-902-1016ND
2019-01-169590-903-092410.00 ppb
2019-01-169590-904-07412.50 ppb
2019-01-169590-905-07533.70 ppb
2019-01-169590-906-08093.50 ppb
2019-01-169590-907-0852ND
2019-04-179590-900-093430.0 ppb
2019-04-179590-901-091831.0 ppb
2019-04-179590-902-09492.10 ppb
2019-04-179590-903-090630.0 ppb
2019-04-179590-904-1012ND
2019-04-179590-905-1028ND
2019-04-179590-906-10553.40 ppb
2019-04-179590-907-11193.90 ppb
2019-07-159590-900-111644.0 ppb
2019-07-159590-901-105643.0 ppb
2019-07-159590-902-112942.0 ppb
2019-07-159590-903-1040ND
2019-07-159590-904-09493.80 ppb
2019-07-159590-905-10093.90 ppb
2019-07-159590-906-09264.10 ppb
2019-07-159590-907-0843ND
2019-08-149590-022-0905ND
2019-08-149590-030-1002ND
2019-08-209590-008-0945ND
2019-08-209590-018-1115ND
2019-08-209590-023-1200ND
2019-08-219590-016-1009ND
2019-08-219590-029-0905ND
2019-08-229590-010-0920ND
2019-10-019590-012-1031ND
2019-10-159590-900-081438.0 ppb
2019-10-159590-901-075839.0 ppb
2019-10-159590-902-083444.0 ppb
2019-10-159590-903-07451.70 ppb
2019-10-159590-904-10178.10 ppb
2019-10-159590-905-0941ND
2019-10-159590-906-095816.0 ppb
2019-10-159590-907-1028ND