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EWG's Tap Water Database — 2021 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.

MORE ABOUT THIS CONTAMINANT

 

240

Samples

0

Samples exceeding legal limit (MCL)

210

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20140.705 ppb3018ND - 3.20 ppb
20151.45 ppb4137ND - 3.90 ppb
20163.10 ppb4035ND - 12.8 ppb
20178.30 ppb4038ND - 26.6 ppb
20185.36 ppb4640ND - 12.3 ppb
20197.96 ppb4342ND - 23.9 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
2014-01-075701-005-1027ND
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
2018-01-095810-005-112011.0 ppb
2018-01-095701-008-11081.21 ppb
2018-01-095810-800-12288.10 ppb
2018-01-095810-801-12026.80 ppb
2018-02-135810-005-11076.20 ppb
2018-02-135810-800-131912.0 ppb
2018-02-135810-801-125910.00 ppb
2018-03-015701-800-08047.09 ppb
2018-03-015701-800-15455.57 ppb
2018-03-015701-801-08065.31 ppb
2018-03-015701-801-08070.950 ppb
2018-03-135701-005-12467.27 ppb
2018-03-135701-800-12489.65 ppb
2018-03-135701-801-124810.4 ppb
2018-04-105701-005-08147.56 ppb
2018-04-105701-800-081310.0 ppb
2018-04-105701-801-08136.03 ppb
2018-05-155701-001-1052ND
2018-05-155701-005-094012.3 ppb
2018-05-155701-006-1038ND
2018-05-155701-800-094110.7 ppb
2018-05-155701-801-094110.8 ppb
2018-06-125701-005-08294.63 ppb
2018-06-125701-800-082811.9 ppb
2018-06-125701-801-08286.56 ppb
2018-07-175701-005-15386.51 ppb
2018-07-175701-800-15056.00 ppb
2018-07-175701-801-15186.94 ppb
2018-08-145701-005-10044.80 ppb
2018-08-145701-800-10047.82 ppb
2018-08-145701-801-10048.82 ppb
2018-08-215701-008-13371.76 ppb
2018-09-185701-005-08301.27 ppb
2018-09-185701-800-08295.25 ppb
2018-09-185701-801-08303.88 ppb
2018-10-025701-005-09100.930 ppb
2018-10-025701-800-09092.23 ppb
2018-10-025701-801-09102.10 ppb
2018-10-305810-800-1538ND
2018-10-305810-801-1519ND
2018-11-135701-005-1005ND
2018-11-135701-800-10060.870 ppb
2018-11-135701-801-1006ND
2018-12-115701-005-13502.83 ppb
2018-12-115701-800-13511.37 ppb
2018-12-115701-801-13511.25 ppb
2019-01-085701-005-08133.11 ppb
2019-01-085701-800-08142.57 ppb
2019-01-085701-801-08142.41 ppb
2019-01-225810-008-11251.80 ppb
2019-02-125810-005-11091.30 ppb
2019-02-125810-800-12292.00 ppb
2019-02-125810-801-12082.00 ppb
2019-03-125701-005-090715.8 ppb
2019-03-125701-800-09085.96 ppb
2019-03-125701-801-090813.2 ppb
2019-04-095701-005-151810.0 ppb
2019-04-095701-800-101422.3 ppb
2019-04-095701-801-100110.5 ppb
2019-05-145701-005-10122.50 ppb
2019-05-145701-800-10117.59 ppb
2019-05-145701-801-10117.59 ppb
2019-06-105701-800-101810.6 ppb
2019-06-105701-801-101810.1 ppb
2019-06-115701-800-10186.56 ppb
2019-06-115701-801-14007.06 ppb
2019-06-255701-005-114618.5 ppb
2019-06-255701-800-115723.9 ppb
2019-06-255701-801-113023.0 ppb
2019-07-165701-005-095911.3 ppb
2019-07-165701-800-120713.4 ppb
2019-07-165701-801-115310.8 ppb
2019-08-135701-005-12525.82 ppb
2019-08-135701-800-13199.08 ppb
2019-08-135701-801-13397.40 ppb
2019-08-205701-008-08394.39 ppb
2019-09-175701-005-12325.89 ppb
2019-09-175701-800-125313.9 ppb
2019-09-175701-801-13047.23 ppb
2019-10-155701-001-1500ND
2019-10-155701-005-15107.60 ppb
2019-10-155701-800-13546.41 ppb
2019-10-155701-801-13397.42 ppb
2019-11-125701-005-12263.04 ppb
2019-11-125701-800-13554.14 ppb
2019-11-125701-801-14083.17 ppb
2019-12-105701-005-14555.13 ppb
2019-12-105701-800-14452.95 ppb
2019-12-105701-801-14312.80 ppb