Bromodichloromethane

City of Palo Alto

Bromodichloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromodichloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

188

Samples

Samples exceeding legal limit (MCL)

111

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	1.20 ppb	32	19	ND - 3.80 ppb
2015	1.29 ppb	32	28	ND - 2.60 ppb
2016	2.33 ppb	32	28	ND - 4.60 ppb
2017	1.98 ppb	32	23	ND - 4.40 ppb
2018	0.171 ppb	35	5	ND - 1.30 ppb
2019	1.22 ppb	25	8	ND - 4.40 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.06 ppb

The EWG Health Guideline of 0.06 ppb for bromodichloromethane 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
2014-03-03	2706-900-1257	ND
2014-03-03	2706-901-1230	ND
2014-03-03	2706-902-0950	ND
2014-03-03	2706-903-1326	ND
2014-03-03	2706-904-1019	1.10 ppb
2014-03-03	2706-905-1120	1.10 ppb
2014-03-03	2706-906-0915	3.80 ppb
2014-03-03	2706-907-1100	ND
2014-06-02	2706-900-1226	ND
2014-06-02	2706-901-1040	ND
2014-06-02	2706-902-1156	ND
2014-06-02	2706-903-1250	ND
2014-06-02	2706-904-1010	ND
2014-06-02	2706-905-0918	ND
2014-06-02	2706-906-1103	ND
2014-06-02	2706-907-0840	ND
2014-09-18	2706-900-1135	2.50 ppb
2014-09-18	2706-901-1115	3.00 ppb
2014-09-18	2706-902-0910	2.80 ppb
2014-09-18	2706-903-1155	2.80 ppb
2014-09-18	2706-904-0940	1.40 ppb
2014-09-18	2706-905-1040	2.80 ppb
2014-09-18	2706-906-0840	3.60 ppb
2014-09-18	2706-907-1015	2.90 ppb
2014-12-01	2706-900-1045	1.30 ppb
2014-12-01	2706-901-1015	1.40 ppb
2014-12-01	2706-902-1320	1.40 ppb
2014-12-01	2706-903-1105	1.40 ppb
2014-12-01	2706-904-1250	1.20 ppb
2014-12-01	2706-905-0925	1.30 ppb
2014-12-01	2706-906-1215	1.40 ppb
2014-12-01	2706-907-0900	1.30 ppb
2015-03-05	2706-900-1130	1.40 ppb
2015-03-05	2706-901-1050	1.30 ppb
2015-03-05	2706-902-0850	1.40 ppb
2015-03-05	2706-903-1155	1.40 ppb
2015-03-05	2706-904-1110	1.30 ppb
2015-03-05	2706-905-1010	1.40 ppb
2015-03-05	2706-906-0925	1.20 ppb
2015-03-05	2706-907-0955	1.40 ppb
2015-06-01	2706-900-1225	1.20 ppb
2015-06-01	2706-901-1110	1.50 ppb
2015-06-01	2706-902-0855	1.30 ppb
2015-06-01	2706-903-1245	1.30 ppb
2015-06-01	2706-904-0925	1.20 ppb
2015-06-01	2706-905-1035	ND
2015-06-01	2706-906-0830	1.50 ppb
2015-06-01	2706-907-1015	ND
2015-09-08	2706-900-1210	1.10 ppb
2015-09-08	2706-901-1058	1.10 ppb
2015-09-08	2706-902-0850	1.20 ppb
2015-09-08	2706-903-1230	1.20 ppb
2015-09-08	2706-904-0920	1.30 ppb
2015-09-08	2706-905-1015	ND
2015-09-08	2706-906-0825	1.20 ppb
2015-09-08	2706-907-0955	ND
2015-12-01	2706-900-1200	1.80 ppb
2015-12-01	2706-901-1130	1.80 ppb
2015-12-01	2706-902-0915	2.60 ppb
2015-12-01	2706-903-1255	1.80 ppb
2015-12-01	2706-904-0945	1.80 ppb
2015-12-01	2706-905-1050	1.70 ppb
2015-12-01	2706-906-0845	2.40 ppb
2015-12-01	2706-907-1030	1.60 ppb
2016-03-07	2706-900-1330	3.80 ppb
2016-03-07	2706-901-1300	3.30 ppb
2016-03-07	2706-902-0845	3.60 ppb
2016-03-07	2706-903-1400	3.60 ppb
2016-03-07	2706-904-1200	3.50 ppb
2016-03-07	2706-905-1125	3.30 ppb
2016-03-07	2706-906-0825	4.00 ppb
2016-03-07	2706-907-1050	3.00 ppb
2016-06-06	2706-900-1155	1.30 ppb
2016-06-06	2706-901-1040	1.80 ppb
2016-06-06	2706-902-1125	1.30 ppb
2016-06-06	2706-903-1205	1.20 ppb
2016-06-06	2706-904-1020	1.40 ppb
2016-06-06	2706-905-0950	1.70 ppb
2016-06-06	2706-906-1105	1.30 ppb
2016-06-06	2706-907-0940	1.70 ppb
2016-09-06	2706-900-1325	ND
2016-09-06	2706-901-1145	1.10 ppb
2016-09-06	2706-902-1235	1.10 ppb
2016-09-06	2706-903-1340	1.000 ppb
2016-09-06	2706-904-1120	ND
2016-09-06	2706-905-1043	ND
2016-09-06	2706-906-1300	1.000 ppb
2016-09-06	2706-907-1020	ND
2016-12-05	2706-900-1205	3.90 ppb
2016-12-05	2706-901-1100	4.40 ppb
2016-12-05	2706-902-0845	4.60 ppb
2016-12-05	2706-903-1230	4.30 ppb
2016-12-05	2706-904-1030	3.40 ppb
2016-12-05	2706-905-1000	2.90 ppb
2016-12-05	2706-906-0820	4.30 ppb
2016-12-05	2706-907-0935	2.70 ppb
2017-03-06	2706-900-1250	3.50 ppb
2017-03-06	2706-901-1045	3.50 ppb
2017-03-06	2706-902-1220	3.70 ppb
2017-03-06	2706-903-1310	3.50 ppb
2017-03-06	2706-904-1020	3.10 ppb
2017-03-06	2706-905-0955	3.20 ppb
2017-03-06	2706-906-1120	3.50 ppb
2017-03-06	2706-907-0930	2.60 ppb
2017-06-05	2706-900-0935	3.10 ppb
2017-06-05	2706-901-1045	3.50 ppb
2017-06-05	2706-902-0850	3.30 ppb
2017-06-05	2706-903-1005	3.50 ppb
2017-06-05	2706-904-1120	4.40 ppb
2017-06-05	2706-905-1200	4.30 ppb
2017-06-05	2706-906-0820	3.40 ppb
2017-06-05	2706-907-1220	3.80 ppb
2017-09-11	2706-900-1300	ND
2017-09-11	2706-901-1145	ND
2017-09-11	2706-902-1207	ND
2017-09-11	2706-903-1320	ND
2017-09-11	2706-904-1125	ND
2017-09-11	2706-905-1100	ND
2017-09-11	2706-906-1235	ND
2017-09-11	2706-907-1040	ND
2017-12-04	2706-900-1330	1.000 ppb
2017-12-04	2706-901-1155	1.20 ppb
2017-12-04	2706-902-1300	1.10 ppb
2017-12-04	2706-903-1345	1.000 ppb
2017-12-04	2706-904-1125	1.000 ppb
2017-12-04	2706-905-1050	1.000 ppb
2017-12-04	2706-906-1230	1.10 ppb
2017-12-04	2706-907-1040	ND
2018-03-05	2706-015-0815	ND
2018-03-05	2706-900-1215	ND
2018-03-05	2706-901-1131	1.30 ppb
2018-03-05	2706-902-1040	ND
2018-03-05	2706-903-1240	ND
2018-03-05	2706-904-1037	1.20 ppb
2018-03-05	2706-905-0932	1.20 ppb
2018-03-05	2706-906-0955	ND
2018-03-05	2706-907-0855	1.20 ppb
2018-06-04	0007-900-1210	ND
2018-06-04	0007-901-1100	ND
2018-06-04	0007-902-0845	ND
2018-06-04	0007-903-1235	ND
2018-06-04	0007-904-1130	ND
2018-06-04	0007-905-1015	ND
2018-06-04	0007-906-0905	ND
2018-06-04	0007-907-0955	ND
2018-09-04	2706-900-1220	ND
2018-09-04	2706-901-1155	ND
2018-09-04	2706-902-0900	ND
2018-09-04	2706-903-1245	ND
2018-09-04	2706-904-1020	ND
2018-09-04	2706-905-1130	ND
2018-09-04	2706-906-0920	ND
2018-09-04	2706-907-1110	ND
2018-12-03	2706-014-1026	ND
2018-12-03	2706-015-0840	ND
2018-12-03	2706-900-1200	ND
2018-12-03	2706-901-1135	1.10 ppb
2018-12-03	2706-902-0930	ND
2018-12-03	2706-903-1220	ND
2018-12-03	2706-904-0955	ND
2018-12-03	2706-905-1055	ND
2018-12-03	2706-906-0910	ND
2018-12-03	2706-907-1035	ND
2019-03-04	2706-900-1140	3.80 ppb
2019-03-04	2706-901-1010	4.40 ppb
2019-03-04	2706-902-0735	4.20 ppb
2019-03-04	2706-903-1225	4.00 ppb
2019-03-04	2706-904-0810	3.90 ppb
2019-03-04	2706-905-0920	3.30 ppb
2019-03-04	2706-906-1040	4.10 ppb
2019-03-04	2706-907-0905	2.70 ppb
2019-08-12	2706-900-1200	ND
2019-08-12	2706-901-1105	ND
2019-08-12	2706-902-0850	ND
2019-08-12	2706-903-1220	ND
2019-08-12	2706-904-0930	ND
2019-08-12	2706-905-1020	ND
2019-08-12	2706-906-0825	ND
2019-08-12	2706-907-1000	ND
2019-11-04	2706-900-1230	ND
2019-11-04	2706-901-1110	ND
2019-11-04	2706-902-0900	ND
2019-11-04	2706-903-1255	ND
2019-11-04	2706-904-0935	ND
2019-11-04	2706-905-1035	ND
2019-11-04	2706-906-0840	ND
2019-11-04	2706-907-1015	ND
2019-12-09	2706-015-0815	ND