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.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 0.705 ppb | 30 | 18 | ND - 3.20 ppb |
2015 | 1.45 ppb | 41 | 37 | ND - 3.90 ppb |
2016 | 3.10 ppb | 40 | 35 | ND - 12.8 ppb |
2017 | 8.30 ppb | 40 | 38 | ND - 26.6 ppb |
2018 | 5.36 ppb | 46 | 40 | ND - 12.3 ppb |
2019 | 7.96 ppb | 43 | 42 | ND - 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 |
---|---|---|
2014-01-07 | 5701-005-1027 | ND |
2014-01-21 | 5701-008-1129 | ND |
2014-02-11 | 5701-005-1017 | 0.520 ppb |
2014-02-18 | 5701-001-1113 | ND |
2014-02-18 | 5701-006-1123 | ND |
2014-03-04 | 5701-005-1454 | ND |
2014-04-08 | 5701-005-1259 | 0.810 ppb |
2014-05-13 | 5701-005-1152 | ND |
2014-05-27 | 5701-001-1212 | ND |
2014-05-27 | 5701-006-1215 | ND |
2014-06-10 | 5701-005-1100 | 0.580 ppb |
2014-07-29 | 5701-005-1230 | 2.56 ppb |
2014-08-12 | 5701-005-1002 | 3.20 ppb |
2014-08-25 | 5701-001-1040 | ND |
2014-08-25 | 5701-006-1055 | ND |
2014-08-25 | 5701-008-1025 | 1.77 ppb |
2014-09-09 | 5701-005-1540 | 0.970 ppb |
2014-09-09 | 5701-800-1457 | 1.26 ppb |
2014-09-09 | 5701-801-1450 | 1.36 ppb |
2014-10-14 | 5701-005-1445 | 0.670 ppb |
2014-10-14 | 5701-800-1402 | 0.870 ppb |
2014-10-14 | 5701-801-1353 | 1.14 ppb |
2014-11-18 | 5701-001-1124 | ND |
2014-11-18 | 5701-006-1130 | ND |
2014-11-25 | 5701-005-1555 | 0.890 ppb |
2014-11-25 | 5701-800-1338 | 0.870 ppb |
2014-11-25 | 5701-801-1326 | 0.860 ppb |
2014-12-16 | 5701-005-1250 | 1.08 ppb |
2014-12-16 | 5701-800-1219 | 0.890 ppb |
2014-12-16 | 5701-801-1227 | 0.850 ppb |
2015-01-13 | 5701-005-1132 | 1.26 ppb |
2015-01-13 | 5701-800-1106 | 0.670 ppb |
2015-01-13 | 5701-801-1058 | 0.610 ppb |
2015-01-20 | 5701-008-1108 | 0.650 ppb |
2015-02-10 | 5701-005-0830 | 0.540 ppb |
2015-02-10 | 5701-800-0829 | 0.500 ppb |
2015-02-10 | 5701-801-0829 | 0.560 ppb |
2015-02-17 | 5701-001-1116 | ND |
2015-02-17 | 5701-006-1128 | ND |
2015-03-10 | 5701-005-0925 | 0.640 ppb |
2015-03-10 | 5701-800-0927 | 0.620 ppb |
2015-03-10 | 5701-801-0928 | 0.580 ppb |
2015-04-07 | 5701-005-0849 | 1.12 ppb |
2015-04-07 | 5701-800-0848 | 0.970 ppb |
2015-04-07 | 5701-801-0848 | 0.930 ppb |
2015-05-13 | 5701-005-0933 | 1.72 ppb |
2015-05-13 | 5701-800-0909 | 3.20 ppb |
2015-05-13 | 5701-801-0931 | 2.41 ppb |
2015-05-19 | 5701-001-1028 | ND |
2015-05-19 | 5701-006-1021 | ND |
2015-06-09 | 5701-005-1022 | 2.23 ppb |
2015-06-09 | 5701-800-0953 | 2.49 ppb |
2015-06-09 | 5701-801-1008 | 2.59 ppb |
2015-07-14 | 5701-005-0850 | 1.88 ppb |
2015-07-14 | 5701-800-0849 | 3.90 ppb |
2015-07-14 | 5701-801-0850 | 3.15 ppb |
2015-08-18 | 5701-005-0836 | 1.20 ppb |
2015-08-18 | 5701-008-1055 | 1.42 ppb |
2015-08-18 | 5701-800-0834 | 2.95 ppb |
2015-08-18 | 5701-801-0837 | 2.56 ppb |
2015-09-15 | 5701-005-0843 | 1.57 ppb |
2015-09-15 | 5701-800-0841 | 2.75 ppb |
2015-09-15 | 5701-801-0842 | 1.99 ppb |
2015-10-13 | 5701-005-1016 | 1.30 ppb |
2015-10-13 | 5701-800-1014 | 1.89 ppb |
2015-10-13 | 5701-801-1015 | 2.00 ppb |
2015-11-09 | 5810-800-1338 | 2.00 ppb |
2015-11-09 | 5810-801-1328 | 1.40 ppb |
2015-12-15 | 5701-005-0800 | 0.860 ppb |
2015-12-15 | 5701-800-0759 | 1.13 ppb |
2015-12-15 | 5701-801-0759 | 1.04 ppb |
2016-01-06 | 5701-005-0910 | 0.860 ppb |
2016-01-06 | 5701-800-0911 | ND |
2016-01-06 | 5701-801-0911 | 0.770 ppb |
2016-01-19 | 5701-008-1500 | ND |
2016-02-09 | 5701-005-0905 | 0.970 ppb |
2016-02-09 | 5701-800-0905 | 0.830 ppb |
2016-02-09 | 5701-801-0905 | 0.700 ppb |
2016-03-08 | 5701-005-0911 | 0.840 ppb |
2016-03-08 | 5701-800-0910 | 0.920 ppb |
2016-03-08 | 5701-801-0911 | 0.880 ppb |
2016-04-12 | 5701-005-0858 | 12.8 ppb |
2016-04-12 | 5701-800-0857 | 3.02 ppb |
2016-04-12 | 5701-801-0857 | 3.03 ppb |
2016-05-10 | 5701-005-0916 | 4.85 ppb |
2016-05-10 | 5810-800-1106 | 9.20 ppb |
2016-05-10 | 5810-801-1056 | 8.50 ppb |
2016-05-24 | 5701-001-1244 | ND |
2016-05-24 | 5701-006-1238 | ND |
2016-06-14 | 5701-005-0819 | 1.59 ppb |
2016-06-14 | 5701-800-0818 | 8.26 ppb |
2016-06-14 | 5701-801-0819 | 12.1 ppb |
2016-07-12 | 5701-005-0827 | 4.19 ppb |
2016-07-12 | 5701-800-0825 | 8.62 ppb |
2016-07-12 | 5701-801-0826 | 7.47 ppb |
2016-08-03 | 9590-008-1045 | 4.30 ppb |
2016-08-09 | 5701-005-0937 | 3.79 ppb |
2016-08-09 | 5701-800-0938 | 6.30 ppb |
2016-08-09 | 5701-801-0939 | 5.23 ppb |
2016-09-13 | 5701-005-0837 | 1.19 ppb |
2016-09-13 | 5701-800-0835 | 3.30 ppb |
2016-09-13 | 5701-801-0836 | 0.920 ppb |
2016-10-18 | 5701-005-0936 | 0.690 ppb |
2016-10-18 | 5701-800-0935 | 1.44 ppb |
2016-10-18 | 5701-801-0936 | 0.590 ppb |
2016-11-15 | 5701-005-0848 | 1.04 ppb |
2016-11-15 | 5701-800-0848 | 0.770 ppb |
2016-11-15 | 5701-801-0849 | 1.14 ppb |
2016-12-13 | 5810-005-1113 | 1.90 ppb |
2016-12-13 | 5810-800-1200 | 1.10 ppb |
2016-12-13 | 5810-801-1140 | ND |
2017-01-17 | 5810-005-1258 | 1.30 ppb |
2017-01-17 | 5810-800-1352 | 1.20 ppb |
2017-01-17 | 5810-801-1337 | 1.20 ppb |
2017-01-24 | 5701-008-1506 | 1.63 ppb |
2017-02-14 | 5701-005-0945 | 8.23 ppb |
2017-02-14 | 5701-800-0942 | 6.68 ppb |
2017-02-14 | 5701-801-0943 | 6.68 ppb |
2017-03-14 | 5810-005-1005 | 23.0 ppb |
2017-03-14 | 5701-800-0827 | 26.6 ppb |
2017-03-14 | 5701-801-0828 | 10.7 ppb |
2017-04-03 | 5701-005-0817 | 10.5 ppb |
2017-04-03 | 5701-800-0817 | 7.55 ppb |
2017-04-03 | 5701-801-0818 | 5.94 ppb |
2017-05-02 | 5701-001-1245 | ND |
2017-05-02 | 5701-006-1241 | ND |
2017-05-09 | 5701-005-0955 | 8.67 ppb |
2017-05-09 | 5701-800-0953 | 16.0 ppb |
2017-05-09 | 5701-801-0954 | 6.94 ppb |
2017-06-13 | 5810-005-1246 | 6.30 ppb |
2017-06-13 | 5810-800-1157 | 13.0 ppb |
2017-06-13 | 5810-801-1210 | 7.20 ppb |
2017-07-11 | 5810-005-1024 | 12.0 ppb |
2017-07-11 | 5810-800-1143 | 17.0 ppb |
2017-07-11 | 5810-801-0956 | 13.0 ppb |
2017-08-08 | 5810-005-1025 | 7.40 ppb |
2017-08-08 | 5810-800-1118 | 16.0 ppb |
2017-08-08 | 5810-801-1058 | 12.0 ppb |
2017-08-22 | 5701-008-1525 | 6.97 ppb |
2017-09-12 | 5810-005-1452 | 7.10 ppb |
2017-09-12 | 5810-800-1411 | 8.40 ppb |
2017-09-12 | 5810-801-1353 | 9.90 ppb |
2017-10-10 | 5810-005-1500 | 6.20 ppb |
2017-10-10 | 5810-800-1331 | 7.60 ppb |
2017-10-10 | 5810-801-1317 | 8.50 ppb |
2017-11-13 | 5810-005-1303 | 4.00 ppb |
2017-11-13 | 5810-800-1358 | 6.90 ppb |
2017-11-13 | 5810-801-1419 | 5.90 ppb |
2017-12-12 | 5701-005-0850 | 4.99 ppb |
2017-12-12 | 5701-800-0850 | 4.71 ppb |
2017-12-12 | 5701-801-0850 | 3.98 ppb |
2018-01-09 | 5810-005-1120 | 11.0 ppb |
2018-01-09 | 5701-008-1108 | 1.21 ppb |
2018-01-09 | 5810-800-1228 | 8.10 ppb |
2018-01-09 | 5810-801-1202 | 6.80 ppb |
2018-02-13 | 5810-005-1107 | 6.20 ppb |
2018-02-13 | 5810-800-1319 | 12.0 ppb |
2018-02-13 | 5810-801-1259 | 10.00 ppb |
2018-03-01 | 5701-800-0804 | 7.09 ppb |
2018-03-01 | 5701-800-1545 | 5.57 ppb |
2018-03-01 | 5701-801-0806 | 5.31 ppb |
2018-03-01 | 5701-801-0807 | 0.950 ppb |
2018-03-13 | 5701-005-1246 | 7.27 ppb |
2018-03-13 | 5701-800-1248 | 9.65 ppb |
2018-03-13 | 5701-801-1248 | 10.4 ppb |
2018-04-10 | 5701-005-0814 | 7.56 ppb |
2018-04-10 | 5701-800-0813 | 10.0 ppb |
2018-04-10 | 5701-801-0813 | 6.03 ppb |
2018-05-15 | 5701-001-1052 | ND |
2018-05-15 | 5701-005-0940 | 12.3 ppb |
2018-05-15 | 5701-006-1038 | ND |
2018-05-15 | 5701-800-0941 | 10.7 ppb |
2018-05-15 | 5701-801-0941 | 10.8 ppb |
2018-06-12 | 5701-005-0829 | 4.63 ppb |
2018-06-12 | 5701-800-0828 | 11.9 ppb |
2018-06-12 | 5701-801-0828 | 6.56 ppb |
2018-07-17 | 5701-005-1538 | 6.51 ppb |
2018-07-17 | 5701-800-1505 | 6.00 ppb |
2018-07-17 | 5701-801-1518 | 6.94 ppb |
2018-08-14 | 5701-005-1004 | 4.80 ppb |
2018-08-14 | 5701-800-1004 | 7.82 ppb |
2018-08-14 | 5701-801-1004 | 8.82 ppb |
2018-08-21 | 5701-008-1337 | 1.76 ppb |
2018-09-18 | 5701-005-0830 | 1.27 ppb |
2018-09-18 | 5701-800-0829 | 5.25 ppb |
2018-09-18 | 5701-801-0830 | 3.88 ppb |
2018-10-02 | 5701-005-0910 | 0.930 ppb |
2018-10-02 | 5701-800-0909 | 2.23 ppb |
2018-10-02 | 5701-801-0910 | 2.10 ppb |
2018-10-30 | 5810-800-1538 | ND |
2018-10-30 | 5810-801-1519 | ND |
2018-11-13 | 5701-005-1005 | ND |
2018-11-13 | 5701-800-1006 | 0.870 ppb |
2018-11-13 | 5701-801-1006 | ND |
2018-12-11 | 5701-005-1350 | 2.83 ppb |
2018-12-11 | 5701-800-1351 | 1.37 ppb |
2018-12-11 | 5701-801-1351 | 1.25 ppb |
2019-01-08 | 5701-005-0813 | 3.11 ppb |
2019-01-08 | 5701-800-0814 | 2.57 ppb |
2019-01-08 | 5701-801-0814 | 2.41 ppb |
2019-01-22 | 5810-008-1125 | 1.80 ppb |
2019-02-12 | 5810-005-1109 | 1.30 ppb |
2019-02-12 | 5810-800-1229 | 2.00 ppb |
2019-02-12 | 5810-801-1208 | 2.00 ppb |
2019-03-12 | 5701-005-0907 | 15.8 ppb |
2019-03-12 | 5701-800-0908 | 5.96 ppb |
2019-03-12 | 5701-801-0908 | 13.2 ppb |
2019-04-09 | 5701-005-1518 | 10.0 ppb |
2019-04-09 | 5701-800-1014 | 22.3 ppb |
2019-04-09 | 5701-801-1001 | 10.5 ppb |
2019-05-14 | 5701-005-1012 | 2.50 ppb |
2019-05-14 | 5701-800-1011 | 7.59 ppb |
2019-05-14 | 5701-801-1011 | 7.59 ppb |
2019-06-10 | 5701-800-1018 | 10.6 ppb |
2019-06-10 | 5701-801-1018 | 10.1 ppb |
2019-06-11 | 5701-800-1018 | 6.56 ppb |
2019-06-11 | 5701-801-1400 | 7.06 ppb |
2019-06-25 | 5701-005-1146 | 18.5 ppb |
2019-06-25 | 5701-800-1157 | 23.9 ppb |
2019-06-25 | 5701-801-1130 | 23.0 ppb |
2019-07-16 | 5701-005-0959 | 11.3 ppb |
2019-07-16 | 5701-800-1207 | 13.4 ppb |
2019-07-16 | 5701-801-1153 | 10.8 ppb |
2019-08-13 | 5701-005-1252 | 5.82 ppb |
2019-08-13 | 5701-800-1319 | 9.08 ppb |
2019-08-13 | 5701-801-1339 | 7.40 ppb |
2019-08-20 | 5701-008-0839 | 4.39 ppb |
2019-09-17 | 5701-005-1232 | 5.89 ppb |
2019-09-17 | 5701-800-1253 | 13.9 ppb |
2019-09-17 | 5701-801-1304 | 7.23 ppb |
2019-10-15 | 5701-001-1500 | ND |
2019-10-15 | 5701-005-1510 | 7.60 ppb |
2019-10-15 | 5701-800-1354 | 6.41 ppb |
2019-10-15 | 5701-801-1339 | 7.42 ppb |
2019-11-12 | 5701-005-1226 | 3.04 ppb |
2019-11-12 | 5701-800-1355 | 4.14 ppb |
2019-11-12 | 5701-801-1408 | 3.17 ppb |
2019-12-10 | 5701-005-1455 | 5.13 ppb |
2019-12-10 | 5701-800-1445 | 2.95 ppb |
2019-12-10 | 5701-801-1431 | 2.80 ppb |