Dibromochloromethane

Windsor

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.

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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	N/A	0	0	N/A
2015	1.72 ppb	12	9	ND - 5.10 ppb
2016	2.26 ppb	16	16	0.540 ppb - 7.30 ppb
2017	1.12 ppb	16	7	ND - 4.30 ppb
2018	1.87 ppb	16	8	ND - 7.60 ppb
2019	0.567 ppb	16	7	ND - 2.30 ppb

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	Result
2015-04-20	1.50 ppb
2015-04-20	1.000 ppb
2015-04-20	1.10 ppb
2015-04-20	1.50 ppb
2015-07-14	5.10 ppb
2015-07-14	ND
2015-07-14	4.40 ppb
2015-07-14	4.90 ppb
2015-10-13	ND
2015-10-13	0.550 ppb
2015-10-13	ND
2015-10-13	0.580 ppb
2016-01-13	1.000 ppb
2016-01-13	0.880 ppb
2016-01-13	0.840 ppb
2016-01-13	1.20 ppb
2016-04-13	1.000 ppb
2016-04-13	0.950 ppb
2016-04-13	0.780 ppb
2016-04-13	0.740 ppb
2016-07-29	7.20 ppb
2016-07-29	7.30 ppb
2016-07-29	6.70 ppb
2016-07-29	5.30 ppb
2016-10-12	0.560 ppb
2016-10-12	0.540 ppb
2016-10-12	0.610 ppb
2016-10-12	0.550 ppb
2017-01-17	ND
2017-01-17	ND
2017-01-17	ND
2017-01-17	ND
2017-04-18	ND
2017-04-18	ND
2017-04-18	ND
2017-04-18	ND
2017-07-18	4.30 ppb
2017-07-18	ND
2017-07-18	2.50 ppb
2017-07-18	3.90 ppb
2017-10-10	1.80 ppb
2017-10-10	0.580 ppb
2017-10-10	2.10 ppb
2017-10-10	2.80 ppb
2018-01-16	ND
2018-01-16	0.540 ppb
2018-01-16	ND
2018-01-16	ND
2018-04-17	0.900 ppb
2018-04-17	ND
2018-04-17	1.10 ppb
2018-04-17	1.60 ppb
2018-07-23	ND
2018-07-23	ND
2018-07-23	ND
2018-07-23	ND
2018-10-23	6.40 ppb
2018-10-23	5.70 ppb
2018-10-23	7.60 ppb
2018-10-23	6.00 ppb
2019-01-30	ND
2019-01-30	ND
2019-01-30	ND
2019-01-30	0.560 ppb
2019-04-23	2.30 ppb
2019-04-23	0.980 ppb
2019-04-23	0.830 ppb
2019-04-23	1.30 ppb
2019-07-23	ND
2019-07-23	ND
2019-07-23	ND
2019-07-23	ND
2019-10-23	1.90 ppb
2019-10-23	ND
2019-10-23	1.20 ppb
2019-10-23	ND