Dibromochloromethane

Elaine Waterworks

Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane 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

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	2.49 ppb	4	2	ND - 9.70 ppb
2015	1.79 ppb	5	3	ND - 7.90 ppb
2016	0.485 ppb	5	3	ND - 1.50 ppb
2017	1.79 ppb	2	2	0.970 ppb - 2.60 ppb
2018	1.90 ppb	4	4	0.364 ppb - 3.80 ppb
2019	ND	2	0	ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for dibromochloromethane 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
2014-05-20	14142005902	9.70 ppb
2014-05-20	14142005802	ND
2014-08-19	14233000503	0.243 ppb
2014-11-18	14324000701	ND
2015-05-05	15127014502	7.90 ppb
2015-09-15	15260001503	0.422 ppb
2015-09-15	15260001509	ND
2015-12-08	15344001903	0.604 ppb
2015-12-08	15344001909	ND
2016-02-16	16049005603	0.349 ppb
2016-02-16	16049005609	ND
2016-05-17	16140007909	ND
2016-05-17	16140007903	0.577 ppb
2016-05-17	16140007802	1.50 ppb
2017-05-31	17152005502	2.60 ppb
2017-05-31	17152005401	0.970 ppb
2018-04-16	18109014601	1.88 ppb
2018-04-24	18116001402	3.80 ppb
2018-07-17	18200000203	0.364 ppb
2018-10-22	18298004303	1.55 ppb
2019-04-24	19115007101	ND
2019-05-14	19136002902	ND