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EWG's Tap Water Database — 2019 UPDATE

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Chloroform

California Water Service Co-leona Valley

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.

 

195

Samples

0

Samples exceeding legal limit (MCL)

153

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20121.49 ppb2314ND - 4.63 ppb
20130.782 ppb2111ND - 3.71 ppb
20140.705 ppb3018ND - 3.20 ppb
20151.45 ppb4137ND - 3.90 ppb
20163.10 ppb4035ND - 12.8 ppb
20178.30 ppb4038ND - 26.6 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
2012-01-115701-005-14004.63 ppb
2012-01-245701-008-12501.17 ppb
2012-02-085701-005-13151.99 ppb
2012-02-285701-001-1410ND
2012-02-285701-006-1415ND
2012-03-125701-005-09284.43 ppb
2012-03-225701-005-14052.16 ppb
2012-04-175701-005-13222.30 ppb
2012-05-085701-005-14053.16 ppb
2012-05-235701-001-1215ND
2012-05-235701-006-1230ND
2012-06-125701-005-14402.07 ppb
2012-07-175701-005-09304.24 ppb
2012-08-145701-005-12562.49 ppb
2012-08-155701-001-1136ND
2012-08-155701-006-1144ND
2012-08-155701-008-11281.95 ppb
2012-09-115701-005-13131.59 ppb
2012-10-095701-005-1251ND
2012-11-195701-001-1217ND
2012-11-195701-005-11440.990 ppb
2012-11-195701-006-1210ND
2012-12-115701-005-12261.01 ppb
2013-01-085701-005-12461.73 ppb
2013-01-225701-008-11350.630 ppb
2013-02-125701-001-1100ND
2013-02-125701-005-13392.90 ppb
2013-02-125701-006-1115ND
2013-04-165701-005-15013.71 ppb
2013-05-145701-005-13051.11 ppb
2013-05-215701-001-1447ND
2013-06-185701-005-10101.42 ppb
2013-07-115701-005-13382.13 ppb
2013-08-155701-005-09410.980 ppb
2013-08-265701-001-1220ND
2013-08-265701-006-1213ND
2013-08-265701-008-12020.590 ppb
2013-09-105701-005-12480.690 ppb
2013-09-185701-005-1046ND
2013-10-085701-005-1034ND
2013-11-125701-005-1338ND
2013-11-195701-001-1045ND
2013-11-195701-006-1056ND
2013-12-105701-005-10380.530 ppb
2014-01-075701-005-1027ND
2014-01-215701-008-1129ND
2014-02-115701-005-10170.520 ppb
2014-02-185701-001-1113ND
2014-02-185701-006-1123ND
2014-03-045701-005-1454ND
2014-04-085701-005-12590.810 ppb
2014-05-135701-005-1152ND
2014-05-275701-001-1212ND
2014-05-275701-006-1215ND
2014-06-105701-005-11000.580 ppb
2014-07-295701-005-12302.56 ppb
2014-08-125701-005-10023.20 ppb
2014-08-255701-001-1040ND
2014-08-255701-006-1055ND
2014-08-255701-008-10251.77 ppb
2014-09-095701-005-15400.970 ppb
2014-09-095701-800-14571.26 ppb
2014-09-095701-801-14501.36 ppb
2014-10-145701-005-14450.670 ppb
2014-10-145701-800-14020.870 ppb
2014-10-145701-801-13531.14 ppb
2014-11-185701-001-1124ND
2014-11-185701-006-1130ND
2014-11-255701-005-15550.890 ppb
2014-11-255701-800-13380.870 ppb
2014-11-255701-801-13260.860 ppb
2014-12-165701-005-12501.08 ppb
2014-12-165701-800-12190.890 ppb
2014-12-165701-801-12270.850 ppb
2015-01-135701-005-11321.26 ppb
2015-01-135701-800-11060.670 ppb
2015-01-135701-801-10580.610 ppb
2015-01-205701-008-11080.650 ppb
2015-02-105701-005-08300.540 ppb
2015-02-105701-800-08290.500 ppb
2015-02-105701-801-08290.560 ppb
2015-02-175701-001-1116ND
2015-02-175701-006-1128ND
2015-03-105701-005-09250.640 ppb
2015-03-105701-800-09270.620 ppb
2015-03-105701-801-09280.580 ppb
2015-04-075701-005-08491.12 ppb
2015-04-075701-800-08480.970 ppb
2015-04-075701-801-08480.930 ppb
2015-05-135701-005-09331.72 ppb
2015-05-135701-800-09093.20 ppb
2015-05-135701-801-09312.41 ppb
2015-05-195701-001-1028ND
2015-05-195701-006-1021ND
2015-06-095701-005-10222.23 ppb
2015-06-095701-800-09532.49 ppb
2015-06-095701-801-10082.59 ppb
2015-07-145701-005-08501.88 ppb
2015-07-145701-800-08493.90 ppb
2015-07-145701-801-08503.15 ppb
2015-08-185701-005-08361.20 ppb
2015-08-185701-008-10551.42 ppb
2015-08-185701-800-08342.95 ppb
2015-08-185701-801-08372.56 ppb
2015-09-155701-005-08431.57 ppb
2015-09-155701-800-08412.75 ppb
2015-09-155701-801-08421.99 ppb
2015-10-135701-005-10161.30 ppb
2015-10-135701-800-10141.89 ppb
2015-10-135701-801-10152.00 ppb
2015-11-095810-800-13382.00 ppb
2015-11-095810-801-13281.40 ppb
2015-12-155701-005-08000.860 ppb
2015-12-155701-800-07591.13 ppb
2015-12-155701-801-07591.04 ppb
2016-01-065701-005-09100.860 ppb
2016-01-065701-800-0911ND
2016-01-065701-801-09110.770 ppb
2016-01-195701-008-1500ND
2016-02-095701-005-09050.970 ppb
2016-02-095701-800-09050.830 ppb
2016-02-095701-801-09050.700 ppb
2016-03-085701-005-09110.840 ppb
2016-03-085701-800-09100.920 ppb
2016-03-085701-801-09110.880 ppb
2016-04-125701-005-085812.8 ppb
2016-04-125701-800-08573.02 ppb
2016-04-125701-801-08573.03 ppb
2016-05-105701-005-09164.85 ppb
2016-05-105810-800-11069.20 ppb
2016-05-105810-801-10568.50 ppb
2016-05-245701-001-1244ND
2016-05-245701-006-1238ND
2016-06-145701-005-08191.59 ppb
2016-06-145701-800-08188.26 ppb
2016-06-145701-801-081912.1 ppb
2016-07-125701-005-08274.19 ppb
2016-07-125701-800-08258.62 ppb
2016-07-125701-801-08267.47 ppb
2016-08-039590-008-10454.30 ppb
2016-08-095701-005-09373.79 ppb
2016-08-095701-800-09386.30 ppb
2016-08-095701-801-09395.23 ppb
2016-09-135701-005-08371.19 ppb
2016-09-135701-800-08353.30 ppb
2016-09-135701-801-08360.920 ppb
2016-10-185701-005-09360.690 ppb
2016-10-185701-800-09351.44 ppb
2016-10-185701-801-09360.590 ppb
2016-11-155701-005-08481.04 ppb
2016-11-155701-800-08480.770 ppb
2016-11-155701-801-08491.14 ppb
2016-12-135810-005-11131.90 ppb
2016-12-135810-800-12001.10 ppb
2016-12-135810-801-1140ND
2017-01-175810-005-12581.30 ppb
2017-01-175810-800-13521.20 ppb
2017-01-175810-801-13371.20 ppb
2017-01-245701-008-15061.63 ppb
2017-02-145701-005-09458.23 ppb
2017-02-145701-800-09426.68 ppb
2017-02-145701-801-09436.68 ppb
2017-03-145810-005-100523.0 ppb
2017-03-145701-800-082726.6 ppb
2017-03-145701-801-082810.7 ppb
2017-04-035701-005-081710.5 ppb
2017-04-035701-800-08177.55 ppb
2017-04-035701-801-08185.94 ppb
2017-05-025701-001-1245ND
2017-05-025701-006-1241ND
2017-05-095701-005-09558.67 ppb
2017-05-095701-800-095316.0 ppb
2017-05-095701-801-09546.94 ppb
2017-06-135810-005-12466.30 ppb
2017-06-135810-800-115713.0 ppb
2017-06-135810-801-12107.20 ppb
2017-07-115810-005-102412.0 ppb
2017-07-115810-800-114317.0 ppb
2017-07-115810-801-095613.0 ppb
2017-08-085810-005-10257.40 ppb
2017-08-085810-800-111816.0 ppb
2017-08-085810-801-105812.0 ppb
2017-08-225701-008-15256.97 ppb
2017-09-125810-005-14527.10 ppb
2017-09-125810-800-14118.40 ppb
2017-09-125810-801-13539.90 ppb
2017-10-105810-005-15006.20 ppb
2017-10-105810-800-13317.60 ppb
2017-10-105810-801-13178.50 ppb
2017-11-135810-005-13034.00 ppb
2017-11-135810-800-13586.90 ppb
2017-11-135810-801-14195.90 ppb
2017-12-125701-005-08504.99 ppb
2017-12-125701-800-08504.71 ppb
2017-12-125701-801-08503.98 ppb