Chloroform

City of Santa Ana

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

391

Samples

Samples exceeding legal limit (MCL)

141

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	4.44 ppb	63	20	ND - 19.0 ppb
2015	4.01 ppb	59	22	ND - 16.9 ppb
2016	2.18 ppb	68	19	ND - 16.5 ppb
2017	2.98 ppb	60	29	ND - 14.6 ppb
2018	1.69 ppb	60	21	ND - 8.60 ppb
2019	1.48 ppb	81	30	ND - 22.7 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
2014-02-18	4417-018-1055	ND
2014-02-18	4417-019-1215	ND
2014-02-18	4417-021-0820	ND
2014-02-18	4417-022-0905	ND
2014-02-18	4417-027-1400	ND
2014-02-18	4417-028-1415	ND
2014-02-18	4417-029-1030	ND
2014-02-18	4417-030-0845	ND
2014-02-18	4417-033-1010	ND
2014-02-18	4417-034-1520	ND
2014-02-18	4417-037-1255	ND
2014-02-18	4417-038-0730	ND
2014-02-18	4417-039-1335	ND
2014-02-18	4417-061-1230	ND
2014-02-18	4417-073-1435	ND
2014-02-18	4417-074-0940	ND
2014-03-11	4417-025-0815	ND
2014-03-11	4417-031-0855	ND
2014-03-12	3761-801-0846	18.5 ppb
2014-03-12	3761-802-0942	10.8 ppb
2014-03-12	3761-803-1009	10.00 ppb
2014-03-12	3761-804-1022	11.0 ppb
2014-03-12	3761-805-1042	12.0 ppb
2014-03-12	3761-806-1055	ND
2014-03-12	3761-807-1106	ND
2014-03-12	3761-808-1127	ND
2014-05-20	4417-018-1015	ND
2014-05-20	4417-019-0835	ND
2014-05-20	4417-025-0810	ND
2014-05-20	4417-074-1005	ND
2014-06-12	3761-801-0831	11.9 ppb
2014-06-12	3761-802-0946	16.3 ppb
2014-06-12	3761-803-1021	16.1 ppb
2014-06-12	3761-804-1031	17.3 ppb
2014-06-12	3761-805-1056	14.0 ppb
2014-06-12	3761-806-1116	13.6 ppb
2014-06-12	3761-807-1131	13.6 ppb
2014-06-12	3761-808-1225	ND
2014-08-12	3761-801-0826	19.0 ppb
2014-08-12	3761-802-0856	17.0 ppb
2014-08-12	3761-803-0936	15.3 ppb
2014-08-12	3761-804-0946	18.0 ppb
2014-08-12	3761-805-1216	15.0 ppb
2014-08-12	3761-806-1226	ND
2014-08-12	3761-807-1241	ND
2014-08-12	3761-808-1301	ND
2014-08-20	4417-018-0915	ND
2014-08-20	4417-019-0645	ND
2014-08-20	4417-025-0725	ND
2014-08-20	4417-035-0710	ND
2014-08-20	4417-074-0925	ND
2014-11-13	4417-018-0900	ND
2014-11-13	4417-019-0840	ND
2014-11-13	4417-025-0820	ND
2014-12-15	3761-801-0856	11.4 ppb
2014-12-15	3761-802-0926	10.1 ppb
2014-12-15	3761-803-0951	ND
2014-12-15	3761-804-1001	ND
2014-12-15	3761-805-1026	9.00 ppb
2014-12-15	3761-806-1041	ND
2014-12-15	3761-807-1051	ND
2014-12-15	3761-808-1126	ND
2014-12-18	4417-026-0800	ND
2015-02-24	4417-018-1110	ND
2015-02-24	4417-019-0840	ND
2015-02-24	4417-028-0905	ND
2015-02-24	4417-029-1145	ND
2015-02-24	4417-031-0950	ND
2015-02-24	4417-033-1135	ND
2015-02-24	4417-034-1215	ND
2015-02-24	4417-037-0810	ND
2015-02-24	4417-038-0735	ND
2015-02-24	4417-039-1020	ND
2015-02-24	4417-073-0940	ND
2015-03-12	3761-801-0916	11.2 ppb
2015-03-12	3761-802-0951	8.50 ppb
2015-03-12	3761-803-1031	7.20 ppb
2015-03-12	3761-804-1041	8.20 ppb
2015-03-12	3761-805-1101	9.00 ppb
2015-03-12	3761-806-1116	ND
2015-03-12	3761-807-1126	ND
2015-03-12	3761-808-1146	3.30 ppb
2015-03-18	4417-025-0745	ND
2015-03-18	4417-061-0805	ND
2015-05-19	4417-019-0840	ND
2015-05-19	4417-021-0705	ND
2015-05-19	4417-022-0735	ND
2015-05-19	4417-025-0805	ND
2015-05-19	4417-026-1010	ND
2015-05-19	4417-030-0720	ND
2015-05-19	4417-074-1050	ND
2015-06-12	3761-801-0820	14.7 ppb
2015-06-12	3761-802-0900	11.9 ppb
2015-06-12	3761-803-0920	11.8 ppb
2015-06-12	3761-804-1015	11.9 ppb
2015-06-12	3761-805-1055	10.8 ppb
2015-06-12	3761-806-1120	ND
2015-06-12	3761-807-1145	ND
2015-06-12	3761-808-1215	5.20 ppb
2015-06-16	4417-027-0635	ND
2015-08-12	4417-018-0625	ND
2015-08-12	4417-019-0525	ND
2015-08-12	4417-025-0510	ND
2015-08-12	4417-035-0540	ND
2015-08-12	3761-801-0900	12.8 ppb
2015-08-12	3761-802-0930	16.8 ppb
2015-08-12	3761-803-1050	16.9 ppb
2015-08-12	3761-804-1055	16.9 ppb
2015-08-12	3761-805-1120	11.4 ppb
2015-08-12	3761-806-1135	12.2 ppb
2015-08-12	3761-807-1145	11.7 ppb
2015-08-12	3761-808-1220	ND
2015-11-17	4417-019-0840	ND
2015-11-17	4417-025-0820	ND
2015-12-08	3761-801-0856	6.50 ppb
2015-12-08	3761-802-0921	9.80 ppb
2015-12-08	3761-803-0931	ND
2015-12-08	3761-804-0941	ND
2015-12-08	3761-805-1001	7.80 ppb
2015-12-08	3761-806-1016	ND
2015-12-08	3761-807-1031	ND
2015-12-08	3761-808-1056	ND
2016-02-16	4417-019-0910	ND
2016-02-16	4417-025-0855	ND
2016-02-16	4417-026-1110	ND
2016-02-16	4417-027-1000	ND
2016-02-16	4417-028-0950	ND
2016-02-16	4417-031-1045	ND
2016-02-16	4417-033-1220	ND
2016-02-16	4417-034-1135	ND
2016-02-16	4417-037-0835	ND
2016-02-16	4417-038-0750	ND
2016-02-16	4417-039-1025	ND
2016-02-16	4417-061-0915	ND
2016-02-16	4417-073-1245	ND
2016-03-07	4417-029-0810	ND
2016-03-08	3761-801-1045	3.90 ppb
2016-03-08	3761-802-0820	2.90 ppb
2016-03-08	3761-803-0955	ND
2016-03-08	3761-804-0940	ND
2016-03-08	3761-805-1120	7.50 ppb
2016-03-08	3761-806-1135	ND
2016-03-08	3761-807-1105	ND
2016-03-08	3761-808-1010	ND
2016-05-24	4417-019-0945	ND
2016-05-24	4417-021-0820	ND
2016-05-24	4417-022-0905	ND
2016-05-24	4417-025-0925	ND
2016-05-24	4417-030-0840	ND
2016-05-24	4417-074-1155	ND
2016-06-15	3761-801-0830	4.70 ppb
2016-06-15	3761-802-0900	11.6 ppb
2016-06-15	3761-803-0930	13.6 ppb
2016-06-15	3761-804-0940	10.9 ppb
2016-06-15	3761-805-1000	5.50 ppb
2016-06-15	3761-806-1010	ND
2016-06-15	3761-807-1030	ND
2016-06-15	3761-808-1100	ND
2016-07-07	4417-025-0630	ND
2016-07-07	4417-025-0640	ND
2016-07-07	4417-030-0600	ND
2016-07-07	4417-030-0605	ND
2016-08-03	4417-018-0800	ND
2016-08-03	4417-019-0915	ND
2016-08-03	4417-028-0955	ND
2016-08-03	4417-033-1100	ND
2016-08-03	4417-034-0710	ND
2016-08-03	4417-035-0830	ND
2016-08-03	4417-037-0845	ND
2016-08-03	4417-038-1025	ND
2016-08-11	3761-801-1145	5.00 ppb
2016-08-11	3761-802-1050	14.1 ppb
2016-08-11	3761-803-0910	15.2 ppb
2016-08-11	3761-804-1030	16.5 ppb
2016-08-11	3761-805-1110	4.30 ppb
2016-08-11	3761-806-1120	4.40 ppb
2016-08-11	3761-807-1130	4.70 ppb
2016-08-11	3761-808-0930	4.60 ppb
2016-10-31	4417-018-0805	ND
2016-10-31	4417-019-0825	ND
2016-10-31	4417-025-0835	ND
2016-10-31	4417-033-0915	ND
2016-12-13	3761-801-1035	6.80 ppb
2016-12-13	3761-802-0850	6.20 ppb
2016-12-13	3761-803-0955	ND
2016-12-13	3761-804-0925	5.50 ppb
2016-12-13	3761-805-1100	ND
2016-12-13	3761-806-1130	ND
2016-12-13	3761-807-1050	ND
2016-12-13	3761-808-1010	ND
2017-02-27	4417-019-0815	ND
2017-02-27	4417-025-0850	ND
2017-02-27	4417-026-1025	ND
2017-02-27	4417-027-0920	ND
2017-02-27	4417-031-1005	ND
2017-02-27	4417-039-0945	ND
2017-02-27	4417-061-0835	ND
2017-03-14	3761-801-0950	7.30 ppb
2017-03-14	3761-802-1020	12.0 ppb
2017-03-14	3761-803-1040	1.70 ppb
2017-03-14	3761-804-1050	3.20 ppb
2017-03-14	3761-805-1115	9.40 ppb
2017-03-14	3761-806-1125	8.70 ppb
2017-03-14	3761-807-1135	7.90 ppb
2017-03-14	3761-808-1155	ND
2017-05-16	4417-019-0950	ND
2017-05-16	4417-021-1140	ND
2017-05-16	4417-022-1205	ND
2017-05-16	4417-025-0830	ND
2017-05-16	4417-028-0915	ND
2017-05-16	4417-030-1150	ND
2017-05-16	4417-031-1040	ND
2017-05-16	4417-034-0750	ND
2017-05-16	4417-035-0940	ND
2017-05-16	4417-037-1230	ND
2017-05-16	4417-038-1115	ND
2017-05-16	4417-074-1020	ND
2017-06-01	4417-073-0915	ND
2017-06-14	3761-801-0750	4.10 ppb
2017-06-14	3761-802-0830	14.6 ppb
2017-06-14	3761-803-0950	10.1 ppb
2017-06-14	3761-804-1000	9.60 ppb
2017-06-14	3761-805-1025	4.30 ppb
2017-06-14	3761-806-1045	3.60 ppb
2017-06-14	3761-807-1055	4.30 ppb
2017-06-14	3761-808-1115	1.60 ppb
2017-08-08	4417-019-0610	ND
2017-08-08	4417-025-0635	ND
2017-08-08	4417-073-0715	ND
2017-08-08	4417-073-0725	ND
2017-08-15	3761-801-0825	12.5 ppb
2017-08-15	3761-802-0845	7.60 ppb
2017-08-15	3761-803-0935	10.00 ppb
2017-08-15	3761-804-0950	9.70 ppb
2017-08-15	3761-805-1020	4.20 ppb
2017-08-15	3761-806-1030	4.20 ppb
2017-08-15	3761-807-1040	4.40 ppb
2017-08-15	3761-808-1100	ND
2017-09-19	4417-073-1100	ND
2017-09-19	4417-073-1110	ND
2017-11-14	4417-019-0930	ND
2017-11-14	4417-025-0855	ND
2017-12-12	3761-801-0920	4.40 ppb
2017-12-12	3761-802-1000	3.10 ppb
2017-12-12	3761-803-1018	2.90 ppb
2017-12-12	3761-804-1030	3.00 ppb
2017-12-12	3761-805-1056	3.30 ppb
2017-12-12	3761-806-1114	3.40 ppb
2017-12-12	3761-807-1125	3.50 ppb
2017-12-12	3761-808-1153	ND
2018-02-21	4417-019-0700	ND
2018-02-21	4417-025-0630	ND
2018-02-21	4417-026-0950	ND
2018-02-21	4417-027-0750	ND
2018-02-21	4417-039-0830	ND
2018-02-21	4417-061-0725	ND
2018-03-13	3761-801-1110	4.40 ppb
2018-03-13	3761-802-0900	2.40 ppb
2018-03-13	3761-803-1240	ND
2018-03-13	3761-804-1212	ND
2018-03-13	3761-805-1120	2.70 ppb
2018-03-13	3761-806-1135	ND
2018-03-13	3761-807-1140	1.40 ppb
2018-03-13	3761-808-1225	ND
2018-04-26	4417-035-0815	ND
2018-05-15	4417-019-0845	ND
2018-05-15	4417-021-0750	ND
2018-05-15	4417-022-1240	ND
2018-05-15	4417-025-1050	ND
2018-05-15	4417-028-0920	ND
2018-05-15	4417-031-0950	ND
2018-05-15	4417-034-1215	ND
2018-05-15	4417-037-0815	ND
2018-05-15	4417-074-1015	ND
2018-06-12	3761-801-0850	5.50 ppb
2018-06-12	3761-802-0935	8.60 ppb
2018-06-12	3761-803-1000	6.60 ppb
2018-06-12	3761-804-1012	7.00 ppb
2018-06-12	3761-805-1035	5.80 ppb
2018-06-12	3761-806-1052	5.50 ppb
2018-06-12	3761-807-1105	5.70 ppb
2018-06-12	3761-808-1133	ND
2018-06-20	4417-030-0815	ND
2018-08-14	3761-801-0845	5.70 ppb
2018-08-14	3761-802-0920	5.60 ppb
2018-08-14	3761-803-0945	4.90 ppb
2018-08-14	3761-804-0955	3.00 ppb
2018-08-14	3761-805-1015	5.10 ppb
2018-08-14	3761-806-1028	5.20 ppb
2018-08-14	3761-807-1039	5.40 ppb
2018-08-14	3761-808-1104	ND
2018-08-21	4417-019-0635	ND
2018-08-21	4417-025-0655	ND
2018-10-11	4417-038-0800	ND
2018-11-06	4417-019-1105	ND
2018-11-06	4417-025-1050	ND
2018-11-06	4417-038-1025	ND
2018-11-06	4417-038-1035	ND
2018-11-13	3761-801-0445	4.20 ppb
2018-11-13	3761-802-0505	3.20 ppb
2018-11-13	3761-803-0525	ND
2018-11-13	3761-804-0540	ND
2018-11-13	3761-805-0600	3.30 ppb
2018-11-13	3761-806-0615	ND
2018-11-13	3761-807-0625	ND
2018-11-13	3761-808-0645	ND
2018-11-13	3761-809-0710	ND
2018-11-13	3761-810-0730	ND
2018-11-13	3761-811-0750	ND
2018-11-13	3761-812-0805	ND
2019-02-12	3761-801-0825	5.10 ppb
2019-02-12	3761-802-1110	4.90 ppb
2019-02-12	3761-803-1400	ND
2019-02-12	3761-804-1422	ND
2019-02-12	3761-805-1130	4.90 ppb
2019-02-12	3761-806-1240	ND
2019-02-12	3761-807-1225	1.60 ppb
2019-02-12	3761-808-1413	ND
2019-02-12	3761-809-1252	ND
2019-02-12	3761-810-1330	ND
2019-02-12	3761-811-1347	ND
2019-02-12	3761-812-1338	ND
2019-03-11	4417-021-0840	ND
2019-03-11	4417-025-0925	ND
2019-03-11	4417-026-1140	ND
2019-03-11	4417-027-1030	ND
2019-03-11	4417-028-1020	ND
2019-03-11	4417-031-1110	ND
2019-03-11	4417-035-1000	ND
2019-03-11	4417-037-0905	ND
2019-03-11	4417-038-0815	ND
2019-03-11	4417-039-1055	ND
2019-03-11	4417-061-0940	ND
2019-03-11	4417-074-1200	ND
2019-03-20	4417-030-1335	ND
2019-03-20	4417-035-1310	ND
2019-03-20	4417-035-1320	ND
2019-04-23	4417-035-0740	ND
2019-04-23	4417-035-0750	ND
2019-05-07	4417-035-0740	ND
2019-05-07	4417-035-0745	ND
2019-05-07	3761-801-0825	5.30 ppb
2019-05-07	3761-802-0857	3.40 ppb
2019-05-07	3761-803-1042	2.90 ppb
2019-05-07	3761-804-1018	2.40 ppb
2019-05-07	3761-805-0924	2.60 ppb
2019-05-07	3761-806-0953	2.50 ppb
2019-05-07	3761-807-0938	2.50 ppb
2019-05-07	3761-808-1031	ND
2019-05-07	3761-809-1155	2.60 ppb
2019-05-07	3761-810-1103	2.80 ppb
2019-05-07	3761-811-1130	1.30 ppb
2019-05-07	3761-812-1120	2.10 ppb
2019-05-29	4417-019-1130	ND
2019-05-29	4417-025-0825	ND
2019-07-23	4417-019-0840	ND
2019-07-23	4417-019-0845	ND
2019-07-23	4417-025-0915	ND
2019-07-23	4417-033-0750	ND
2019-07-23	4417-034-1020	ND
2019-07-23	4417-035-0855	ND
2019-08-13	3761-801-1210	5.60 ppb
2019-08-13	3761-802-0948	5.90 ppb
2019-08-13	3761-803-0724	3.80 ppb
2019-08-13	3761-804-0741	3.40 ppb
2019-08-13	3761-805-1039	3.80 ppb
2019-08-13	3761-806-1020	3.60 ppb
2019-08-13	3761-807-1057	1.80 ppb
2019-08-13	3761-808-0804	3.70 ppb
2019-08-13	3761-809-1117	3.20 ppb
2019-08-13	3761-810-0118	ND
2019-08-13	3761-811-1251	1.20 ppb
2019-08-13	3761-812-1236	22.7 ppb
2019-09-17	4417-073-0815	ND
2019-11-05	4417-019-1105	ND
2019-11-05	4417-022-1030	ND
2019-11-05	4417-025-1125	ND
2019-11-05	4417-073-0955	ND
2019-11-05	4417-073-1505	ND
2019-11-12	3761-801-0646	5.40 ppb
2019-11-12	3761-802-0756	3.90 ppb
2019-11-12	3761-803-0532	ND
2019-11-12	3761-804-0550	ND
2019-11-12	3761-805-1131	2.70 ppb
2019-11-12	3761-806-1141	ND
2019-11-12	3761-807-1123	ND
2019-11-12	3761-808-0542	ND
2019-11-12	3761-809-0706	ND
2019-11-12	3761-810-0625	2.30 ppb
2019-11-12	3761-811-0613	ND
2019-11-12	3761-812-0604	ND