Chloroform
City of Corona
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.
339
Samples
0
Samples exceeding legal limit (MCL)
156
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2012 | 3.06 ppb | 61 | 34 | ND - 13.0 ppb |
| 2013 | 2.17 ppb | 71 | 31 | ND - 17.0 ppb |
| 2014 | 1.91 ppb | 60 | 25 | ND - 12.0 ppb |
| 2015 | 1.72 ppb | 55 | 21 | ND - 11.0 ppb |
| 2016 | 2.42 ppb | 42 | 15 | ND - 14.0 ppb |
| 2017 | 3.59 ppb | 50 | 30 | ND - 16.0 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 |
|---|---|---|
| 2012-03-12 | 4790-019-1345 | 6.20 ppb |
| 2012-03-12 | 4790-036-1400 | 2.10 ppb |
| 2012-03-12 | 4790-041-1445 | ND |
| 2012-03-12 | 4790-043-1100 | 2.80 ppb |
| 2012-03-12 | 4790-049-1025 | 2.30 ppb |
| 2012-06-04 | 4790-019-0940 | 9.50 ppb |
| 2012-06-04 | 4790-036-1325 | 7.80 ppb |
| 2012-06-04 | 4790-041-1300 | ND |
| 2012-06-04 | 4790-801-1000 | 11.0 ppb |
| 2012-06-04 | 4790-802-1140 | ND |
| 2012-06-04 | 4790-803-1530 | 13.0 ppb |
| 2012-06-04 | 4790-804-1430 | 12.0 ppb |
| 2012-06-04 | 4790-805-1410 | 2.50 ppb |
| 2012-06-04 | 4790-806-1110 | 11.0 ppb |
| 2012-06-04 | 4790-807-1325 | 5.70 ppb |
| 2012-06-04 | 4790-808-1105 | 9.70 ppb |
| 2012-06-13 | 4790-003-1145 | ND |
| 2012-06-13 | 4790-013-1115 | ND |
| 2012-06-13 | 4790-022-1030 | ND |
| 2012-06-13 | 4790-023-1230 | ND |
| 2012-06-13 | 4790-030-1200 | ND |
| 2012-06-13 | 4790-033-1300 | ND |
| 2012-06-20 | 4790-014-1550 | ND |
| 2012-06-20 | 4790-015-1450 | ND |
| 2012-06-20 | 4790-027-0930 | ND |
| 2012-06-20 | 4790-032-1035 | ND |
| 2012-06-20 | 4790-038-1310 | ND |
| 2012-06-21 | 4790-019-0950 | 6.00 ppb |
| 2012-06-21 | 4790-034-1300 | ND |
| 2012-06-21 | 4790-043-1220 | 9.30 ppb |
| 2012-06-21 | 4790-052-1040 | ND |
| 2012-06-22 | 4790-039-0730 | ND |
| 2012-06-27 | 4790-024-0930 | ND |
| 2012-06-27 | 4790-029-1400 | ND |
| 2012-06-27 | 4790-031-1450 | ND |
| 2012-06-27 | 4790-054-1120 | ND |
| 2012-06-27 | 4790-056-1030 | 1.20 ppb |
| 2012-06-27 | 4790-062-1020 | ND |
| 2012-09-11 | 4790-019-1050 | 4.70 ppb |
| 2012-09-11 | 4790-036-1155 | 4.70 ppb |
| 2012-09-11 | 4790-041-1150 | ND |
| 2012-09-11 | 4790-801-1050 | 11.0 ppb |
| 2012-09-11 | 4790-802-1135 | ND |
| 2012-09-11 | 4790-803-0825 | 5.50 ppb |
| 2012-09-11 | 4790-804-0855 | 6.60 ppb |
| 2012-09-11 | 4790-805-0800 | 3.80 ppb |
| 2012-09-11 | 4790-806-1115 | 7.90 ppb |
| 2012-09-11 | 4790-807-1330 | 1.50 ppb |
| 2012-09-11 | 4790-808-1035 | 4.60 ppb |
| 2012-12-04 | 4790-055-0900 | ND |
| 2012-12-10 | 4790-019-1050 | 2.80 ppb |
| 2012-12-10 | 4790-036-1200 | 2.70 ppb |
| 2012-12-10 | 4790-041-1145 | ND |
| 2012-12-10 | 4790-801-0910 | 7.40 ppb |
| 2012-12-10 | 4790-802-1100 | ND |
| 2012-12-10 | 4790-803-1010 | 0.810 ppb |
| 2012-12-10 | 4790-804-0900 | 1.40 ppb |
| 2012-12-10 | 4790-805-0940 | 2.70 ppb |
| 2012-12-10 | 4790-806-1045 | 2.20 ppb |
| 2012-12-10 | 4790-807-1130 | 1.20 ppb |
| 2012-12-10 | 4790-808-1400 | 2.90 ppb |
| 2013-02-06 | 4790-021-0930 | ND |
| 2013-02-06 | 4790-027-1330 | ND |
| 2013-02-06 | 4790-030-1130 | ND |
| 2013-02-06 | 4790-039-1130 | ND |
| 2013-02-13 | 4790-052-1510 | ND |
| 2013-02-13 | 4790-054-1350 | ND |
| 2013-02-13 | 4790-062-1440 | ND |
| 2013-03-11 | 4790-019-0830 | ND |
| 2013-03-11 | 4790-036-1345 | 0.570 ppb |
| 2013-03-11 | 4790-041-1450 | ND |
| 2013-03-11 | 4790-801-1120 | 7.80 ppb |
| 2013-03-11 | 4790-802-1305 | 1.60 ppb |
| 2013-03-11 | 4790-803-1615 | ND |
| 2013-03-11 | 4790-804-1520 | ND |
| 2013-03-11 | 4790-805-1625 | ND |
| 2013-03-11 | 4790-806-1250 | 6.00 ppb |
| 2013-03-11 | 4790-807-1120 | 2.90 ppb |
| 2013-03-11 | 4790-808-0925 | 1.30 ppb |
| 2013-05-01 | 4790-024-1230 | ND |
| 2013-05-01 | 4790-038-1050 | ND |
| 2013-05-08 | 4790-003-1440 | ND |
| 2013-05-08 | 4790-022-1400 | ND |
| 2013-05-08 | 4790-023-0910 | ND |
| 2013-05-16 | 4790-019-1340 | 5.10 ppb |
| 2013-05-16 | 4790-034-0915 | ND |
| 2013-05-16 | 4790-043-1050 | 7.70 ppb |
| 2013-06-10 | 4790-019-1510 | 5.80 ppb |
| 2013-06-10 | 4790-036-1345 | 4.60 ppb |
| 2013-06-10 | 4790-041-0920 | ND |
| 2013-06-10 | 4790-801-1115 | 17.0 ppb |
| 2013-06-10 | 4790-802-1210 | 2.10 ppb |
| 2013-06-10 | 4790-803-1130 | 4.40 ppb |
| 2013-06-10 | 4790-804-1030 | 5.50 ppb |
| 2013-06-10 | 4790-805-1150 | ND |
| 2013-06-10 | 4790-806-1145 | 6.60 ppb |
| 2013-06-10 | 4790-807-1240 | 2.10 ppb |
| 2013-06-10 | 4790-808-1220 | 5.80 ppb |
| 2013-06-12 | 4790-055-1135 | ND |
| 2013-06-26 | 4790-028-0900 | ND |
| 2013-08-07 | 9590-032-0940 | ND |
| 2013-08-15 | 9590-033-0900 | ND |
| 2013-08-15 | 9590-056-1435 | ND |
| 2013-08-21 | 9590-029-1002 | ND |
| 2013-08-22 | 9590-013-0940 | ND |
| 2013-08-22 | 9590-014-1500 | ND |
| 2013-08-22 | 9590-015-1402 | ND |
| 2013-08-22 | 9590-031-0825 | ND |
| 2013-09-04 | 9590-055-1115 | ND |
| 2013-09-09 | 9590-019-1345 | 7.20 ppb |
| 2013-09-09 | 9590-036-1325 | 4.40 ppb |
| 2013-09-09 | 9590-041-1410 | ND |
| 2013-09-09 | 9590-801-1230 | 11.0 ppb |
| 2013-09-09 | 9590-802-1345 | 1.10 ppb |
| 2013-09-09 | 9590-803-1710 | 4.40 ppb |
| 2013-09-09 | 9590-804-1650 | 4.80 ppb |
| 2013-09-09 | 9590-805-1730 | 2.10 ppb |
| 2013-09-09 | 9590-806-1450 | 6.00 ppb |
| 2013-09-09 | 9590-807-0904 | 2.00 ppb |
| 2013-09-09 | 9590-808-1027 | 4.00 ppb |
| 2013-12-10 | 9590-055-0845 | ND |
| 2013-12-16 | 9590-019-1430 | ND |
| 2013-12-16 | 9590-036-1300 | ND |
| 2013-12-16 | 9590-041-1330 | ND |
| 2013-12-16 | 9590-801-1040 | 6.20 ppb |
| 2013-12-16 | 9590-802-1150 | ND |
| 2013-12-16 | 9590-803-1400 | ND |
| 2013-12-16 | 9590-804-1450 | ND |
| 2013-12-16 | 9590-805-1430 | ND |
| 2013-12-16 | 9590-806-1130 | 5.00 ppb |
| 2013-12-16 | 9590-807-0900 | 1.20 ppb |
| 2013-12-16 | 9590-808-0945 | 7.70 ppb |
| 2014-02-12 | 9590-021-0900 | ND |
| 2014-02-12 | 9590-027-1020 | ND |
| 2014-02-12 | 9590-028-1450 | ND |
| 2014-02-12 | 9590-039-1100 | ND |
| 2014-02-12 | 9590-052-1145 | ND |
| 2014-02-12 | 9590-054-1355 | 1.50 ppb |
| 2014-02-26 | 9590-030-0730 | ND |
| 2014-03-03 | 9590-019-1345 | ND |
| 2014-03-03 | 9590-036-1430 | 1.70 ppb |
| 2014-03-03 | 9590-041-1505 | ND |
| 2014-03-03 | 9590-801-1315 | 11.0 ppb |
| 2014-03-03 | 9590-802-1510 | ND |
| 2014-03-03 | 9590-803-1229 | ND |
| 2014-03-03 | 9590-804-1026 | ND |
| 2014-03-03 | 9590-805-1305 | ND |
| 2014-03-03 | 9590-806-1435 | 1.90 ppb |
| 2014-03-03 | 9590-807-0855 | 1.70 ppb |
| 2014-03-03 | 9590-808-1135 | ND |
| 2014-03-12 | 9590-055-1120 | ND |
| 2014-05-14 | 9590-024-1325 | ND |
| 2014-05-14 | 9590-038-1035 | ND |
| 2014-05-14 | 9590-043-0915 | 7.30 ppb |
| 2014-05-15 | 9590-019-1155 | 5.50 ppb |
| 2014-05-15 | 9590-022-0850 | ND |
| 2014-05-15 | 9590-023-1005 | ND |
| 2014-05-15 | 9590-034-1500 | ND |
| 2014-06-02 | 9590-801-1200 | 8.90 ppb |
| 2014-06-02 | 9590-802-1045 | 2.60 ppb |
| 2014-06-02 | 9590-803-0825 | 3.80 ppb |
| 2014-06-02 | 9590-804-0850 | 3.90 ppb |
| 2014-06-02 | 9590-805-0920 | 2.00 ppb |
| 2014-06-02 | 9590-806-1230 | 4.90 ppb |
| 2014-06-02 | 9590-807-0950 | 1.20 ppb |
| 2014-06-02 | 9590-808-1020 | 5.30 ppb |
| 2014-08-13 | 9590-015-0930 | ND |
| 2014-08-13 | 9590-031-1455 | ND |
| 2014-08-13 | 9590-032-1100 | ND |
| 2014-08-13 | 9590-033-1315 | ND |
| 2014-08-21 | 9590-029-0900 | ND |
| 2014-08-26 | 9590-003-1400 | ND |
| 2014-08-27 | 9590-014-1315 | ND |
| 2014-08-27 | 9590-056-1415 | ND |
| 2014-08-28 | 9590-013-1030 | ND |
| 2014-09-15 | 9590-801-1300 | 12.0 ppb |
| 2014-09-15 | 9590-802-1400 | 4.10 ppb |
| 2014-09-15 | 9590-803-0815 | 4.60 ppb |
| 2014-09-15 | 9590-804-0910 | 5.20 ppb |
| 2014-09-15 | 9590-805-0935 | 2.10 ppb |
| 2014-09-15 | 9590-806-1330 | 7.40 ppb |
| 2014-09-15 | 9590-807-1010 | 2.20 ppb |
| 2014-09-15 | 9590-808-1130 | 5.20 ppb |
| 2014-09-16 | 9590-054-1500 | ND |
| 2014-12-15 | 9590-801-1420 | 7.10 ppb |
| 2014-12-15 | 9590-802-1340 | ND |
| 2014-12-15 | 9590-803-0850 | ND |
| 2014-12-15 | 9590-804-0920 | ND |
| 2014-12-15 | 9590-805-0950 | ND |
| 2014-12-15 | 9590-807-1020 | 1.60 ppb |
| 2014-12-15 | 9590-808-1135 | ND |
| 2014-12-15 | 9590-809-1040 | ND |
| 2015-02-03 | 9590-030-1000 | 1.40 ppb |
| 2015-02-12 | 9590-027-0900 | ND |
| 2015-02-12 | 9590-028-1420 | ND |
| 2015-02-12 | 9590-030-0810 | ND |
| 2015-02-12 | 9590-039-0950 | ND |
| 2015-02-12 | 9590-052-1330 | 1.60 ppb |
| 2015-03-09 | 9590-801-1250 | 6.40 ppb |
| 2015-03-09 | 9590-802-1230 | 1.80 ppb |
| 2015-03-09 | 9590-803-0900 | ND |
| 2015-03-09 | 9590-804-0935 | ND |
| 2015-03-09 | 9590-805-1015 | ND |
| 2015-03-09 | 9590-807-1040 | ND |
| 2015-03-09 | 9590-808-1320 | ND |
| 2015-03-09 | 9590-809-1110 | ND |
| 2015-05-28 | 9590-003-0940 | ND |
| 2015-05-28 | 9590-019-1045 | 5.40 ppb |
| 2015-05-28 | 9590-024-0930 | ND |
| 2015-05-28 | 9590-034-0830 | ND |
| 2015-05-28 | 9590-038-1000 | ND |
| 2015-05-28 | 9590-043-1100 | 8.70 ppb |
| 2015-06-08 | 9590-801-1450 | 9.20 ppb |
| 2015-06-08 | 9590-802-1420 | 2.00 ppb |
| 2015-06-08 | 9590-803-0900 | 3.60 ppb |
| 2015-06-08 | 9590-804-0940 | 3.20 ppb |
| 2015-06-08 | 9590-805-1010 | ND |
| 2015-06-08 | 9590-807-1040 | 2.20 ppb |
| 2015-06-08 | 9590-808-1340 | 6.30 ppb |
| 2015-06-08 | 9590-809-1100 | 2.60 ppb |
| 2015-06-09 | 9590-062-0815 | ND |
| 2015-08-12 | 9590-029-0900 | ND |
| 2015-08-12 | 9590-031-1020 | ND |
| 2015-08-12 | 9590-032-1100 | ND |
| 2015-08-12 | 9590-056-0940 | ND |
| 2015-08-20 | 9590-013-0900 | ND |
| 2015-08-20 | 9590-014-1430 | ND |
| 2015-08-20 | 9590-015-1130 | ND |
| 2015-08-20 | 9590-033-0950 | ND |
| 2015-09-17 | 9590-801-1120 | 11.0 ppb |
| 2015-09-17 | 9590-802-1100 | ND |
| 2015-09-17 | 9590-803-0815 | 1.30 ppb |
| 2015-09-17 | 9590-804-0840 | ND |
| 2015-09-17 | 9590-805-0900 | 2.30 ppb |
| 2015-09-17 | 9590-807-0910 | 1.60 ppb |
| 2015-09-17 | 9590-808-1040 | 4.80 ppb |
| 2015-09-17 | 9590-809-1020 | 6.70 ppb |
| 2015-10-14 | 9590-023-0930 | ND |
| 2015-10-14 | 9590-054-1330 | 3.00 ppb |
| 2015-12-23 | 9590-801-1015 | 9.50 ppb |
| 2015-12-23 | 9590-802-1130 | ND |
| 2015-12-23 | 9590-803-0910 | ND |
| 2015-12-23 | 9590-804-0945 | ND |
| 2015-12-23 | 9590-805-0930 | ND |
| 2015-12-23 | 9590-807-1510 | ND |
| 2015-12-23 | 9590-808-1420 | ND |
| 2015-12-23 | 9590-809-1440 | ND |
| 2016-03-09 | 9590-801-1025 | 5.40 ppb |
| 2016-03-09 | 9590-802-1050 | ND |
| 2016-03-09 | 9590-803-1110 | ND |
| 2016-03-09 | 9590-804-0840 | ND |
| 2016-03-09 | 9590-805-0910 | ND |
| 2016-03-09 | 9590-807-1330 | ND |
| 2016-03-09 | 9590-808-1440 | ND |
| 2016-03-09 | 9590-809-1400 | ND |
| 2016-04-13 | 9590-027-0950 | ND |
| 2016-04-13 | 9590-028-0800 | ND |
| 2016-04-13 | 9590-030-0850 | ND |
| 2016-04-21 | 9590-054-1340 | ND |
| 2016-04-27 | 9590-062-1320 | ND |
| 2016-06-09 | 9590-801-1151 | 8.60 ppb |
| 2016-06-09 | 9590-802-1045 | ND |
| 2016-06-09 | 9590-803-0827 | 5.30 ppb |
| 2016-06-09 | 9590-804-0852 | 5.40 ppb |
| 2016-06-09 | 9590-805-0910 | 5.70 ppb |
| 2016-06-09 | 9590-807-0936 | 3.20 ppb |
| 2016-06-09 | 9590-808-1028 | 7.30 ppb |
| 2016-06-09 | 9590-809-1006 | 3.70 ppb |
| 2016-07-20 | 9590-039-1045 | ND |
| 2016-08-18 | 9590-003-1000 | ND |
| 2016-08-18 | 9590-023-1050 | ND |
| 2016-08-18 | 9590-038-1400 | ND |
| 2016-08-23 | 9590-024-1430 | ND |
| 2016-08-24 | 9590-019-1030 | 6.80 ppb |
| 2016-08-24 | 9590-034-0900 | ND |
| 2016-08-24 | 9590-043-1430 | 8.80 ppb |
| 2016-09-13 | 9590-802-1350 | 1.10 ppb |
| 2016-09-13 | 9590-808-1450 | 13.0 ppb |
| 2016-09-13 | 9590-809-1440 | 14.0 ppb |
| 2016-10-11 | 9590-031-1530 | ND |
| 2016-10-12 | 9590-032-1430 | ND |
| 2016-10-20 | 9590-029-1400 | ND |
| 2016-10-27 | 9590-014-0915 | ND |
| 2016-10-27 | 9590-015-1020 | ND |
| 2016-10-27 | 9590-033-1400 | ND |
| 2016-10-27 | 9590-056-0840 | ND |
| 2016-12-15 | 9590-802-1350 | ND |
| 2016-12-15 | 9590-808-1010 | 6.50 ppb |
| 2016-12-15 | 9590-809-0950 | 6.70 ppb |
| 2017-03-16 | 9590-801-0900 | 6.60 ppb |
| 2017-03-16 | 9590-802-0950 | ND |
| 2017-03-16 | 9590-803-1120 | 3.80 ppb |
| 2017-03-16 | 9590-804-1030 | 3.40 ppb |
| 2017-03-16 | 9590-805-1100 | ND |
| 2017-03-16 | 9590-807-1520 | 15.0 ppb |
| 2017-03-16 | 9590-808-1420 | 16.0 ppb |
| 2017-03-16 | 9590-809-1440 | 16.0 ppb |
| 2017-04-12 | 9590-030-1000 | ND |
| 2017-04-12 | 9590-054-1400 | ND |
| 2017-04-12 | 9590-062-1500 | ND |
| 2017-04-20 | 9590-027-1400 | ND |
| 2017-04-20 | 9590-038-0920 | ND |
| 2017-04-20 | 9590-039-1500 | ND |
| 2017-06-15 | 9590-801-1120 | 4.60 ppb |
| 2017-06-15 | 9590-802-1540 | ND |
| 2017-06-15 | 9590-803-0920 | 3.40 ppb |
| 2017-06-15 | 9590-804-0945 | 3.90 ppb |
| 2017-06-15 | 9590-805-1010 | 2.90 ppb |
| 2017-06-15 | 9590-807-1340 | 4.60 ppb |
| 2017-06-15 | 9590-808-1430 | 4.60 ppb |
| 2017-06-15 | 9590-809-1400 | 4.70 ppb |
| 2017-08-09 | 9590-019-1030 | 5.30 ppb |
| 2017-08-09 | 9590-023-0945 | ND |
| 2017-08-09 | 9590-024-1400 | ND |
| 2017-08-09 | 9590-043-1530 | 5.10 ppb |
| 2017-08-10 | 9590-034-1220 | ND |
| 2017-09-13 | 9590-801-1100 | 11.0 ppb |
| 2017-09-13 | 9590-802-1400 | 3.10 ppb |
| 2017-09-13 | 9590-803-0850 | 6.30 ppb |
| 2017-09-13 | 9590-804-0910 | 8.50 ppb |
| 2017-09-13 | 9590-805-0930 | 6.80 ppb |
| 2017-09-13 | 9590-807-1000 | 6.20 ppb |
| 2017-09-13 | 9590-808-1440 | 7.40 ppb |
| 2017-09-13 | 9590-809-1520 | 6.10 ppb |
| 2017-10-12 | 9590-015-1500 | ND |
| 2017-10-12 | 9590-031-0930 | ND |
| 2017-10-12 | 9590-032-1030 | ND |
| 2017-10-19 | 9590-014-1030 | ND |
| 2017-10-19 | 9590-029-1500 | ND |
| 2017-10-19 | 9590-056-1400 | ND |
| 2017-10-26 | 9590-033-1000 | ND |
| 2017-12-14 | 9590-801-1350 | 6.40 ppb |
| 2017-12-14 | 9590-802-1450 | ND |
| 2017-12-14 | 9590-803-0830 | 2.30 ppb |
| 2017-12-14 | 9590-804-0855 | 1.80 ppb |
| 2017-12-14 | 9590-805-0925 | 2.50 ppb |
| 2017-12-14 | 9590-807-0945 | 3.00 ppb |
| 2017-12-14 | 9590-808-1020 | 4.20 ppb |
| 2017-12-14 | 9590-809-1010 | 3.80 ppb |