Bromate

Seattle Public Utilities

Bromate is a carcinogenic disinfection byproduct formed when source waters containing bromide are treated with ozonation or sodium hypochlorite. Studies of laboratory animals show that bromate damages DNA and causes cancer in multiple organs. Click here to read more about disinfection byproducts.

MORE ABOUT THIS CONTAMINANT

211

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	0.0694 ppb	36	2	ND - 1.50 ppb
2015	0.000125 ppb	36	3	ND - 0.00200 ppb
2016	0 ppb	35	1	ND - 0.001000 ppb
2017	0.000111 ppb	36	3	ND - 0.00200 ppb
2018	ND	37	0	ND
2019	ND	31	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 bromate was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL) 10 ppb

The legal limit for bromate, established in 1998, was based on analytical detection limits at the time that the standard was set. This limit may not fully protect against the risk of cancer due to bromate exposure.

ppb = parts per billion

All test results

Date	Lab ID	Result
2014-01-01	00990	ND
2014-01-08	00991	ND
2014-01-14	02154	ND
2014-02-05	05732	ND
2014-02-05	05731	ND
2014-02-11	06378	ND
2014-03-05	09898	ND
2014-03-05	09899	ND
2014-03-11	10614	1.50 ppb
2014-04-02	14479	ND
2014-04-02	14480	ND
2014-04-08	14976	ND
2014-05-07	21003	ND
2014-05-07	21004	ND
2014-05-13	20781	ND
2014-06-04	25081	ND
2014-06-04	25080	ND
2014-06-10	25265	ND
2014-07-02	29282	ND
2014-07-02	29283	ND
2014-07-08	29674	ND
2014-08-06	34838	ND
2014-08-06	34837	ND
2014-08-12	35741	ND
2014-09-03	39782	ND
2014-09-03	39783	ND
2014-09-09	40755	ND
2014-10-01	45948	ND
2014-10-01	45949	ND
2014-10-13	45923	ND
2014-11-05	50711	ND
2014-11-05	50712	ND
2014-11-11	50357	ND
2014-12-03	54641	ND
2014-12-03	54642	ND
2014-12-09	54514	1.000 ppb
2015-01-07	01659	ND
2015-01-07	01658	ND
2015-01-13	02030	ND
2015-02-04	05645	ND
2015-02-04	05644	ND
2015-02-10	06315	ND
2015-03-04	09626	ND
2015-03-04	09625	ND
2015-03-10	10206	ND
2015-04-01	14405	ND
2015-04-01	14404	ND
2015-04-14	16065	ND
2015-05-06	21441	ND
2015-05-06	21440	ND
2015-05-12	21200	ND
2015-06-03	25925	ND
2015-06-09	26350	ND
2015-06-09	25926	ND
2015-07-01	31132	ND
2015-07-01	31131	ND
2015-07-14	32099	ND
2015-08-11	37370	ND
2015-08-12	38912	ND
2015-08-12	38911	ND
2015-09-02	42974	ND
2015-09-02	42973	ND
2015-09-08	42488	ND
2015-10-07	49061	ND
2015-10-07	49060	ND
2015-10-13	49471	0.001000 ppb
2015-11-04	54090	ND
2015-11-04	54089	ND
2015-11-11	54542	0.00200 ppb
2015-12-02	60627	ND
2015-12-02	60626	ND
2015-12-08	59127	0.00150 ppb
2016-01-06		ND
2016-01-06		ND
2016-01-12		ND
2016-02-03		ND
2016-02-03		ND
2016-02-09		ND
2016-03-02		ND
2016-03-02		ND
2016-03-08		ND
2016-04-06		ND
2016-04-06		ND
2016-04-12		ND
2016-05-04		ND
2016-05-04		ND
2016-05-10		ND
2016-06-01		ND
2016-06-01		ND
2016-07-06		ND
2016-07-06		ND
2016-07-12		ND
2016-08-03		ND
2016-08-03		ND
2016-08-09		ND
2016-09-07		ND
2016-09-07		ND
2016-09-13		ND
2016-10-08		ND
2016-10-08		ND
2016-10-11		ND
2016-11-02		ND
2016-11-02		ND
2016-11-08		0.001000 ppb
2016-12-05		ND
2016-12-07		ND
2016-12-07		ND
2017-01-03		ND
2017-01-04		ND
2017-01-04		ND
2017-02-01		ND
2017-02-01		0.001000 ppb
2017-02-06		0.00200 ppb
2017-03-01		ND
2017-03-01		ND
2017-03-06		ND
2017-04-03		ND
2017-04-05		ND
2017-04-05		ND
2017-05-01		ND
2017-05-03		ND
2017-05-03		ND
2017-06-05		ND
2017-06-07		ND
2017-06-07		ND
2017-07-05		ND
2017-07-05		ND
2017-07-05		ND
2017-08-01		ND
2017-08-02		ND
2017-08-02		ND
2017-09-05		ND
2017-09-06		ND
2017-09-06		ND
2017-10-02		ND
2017-10-04		ND
2017-10-04		ND
2017-11-01		ND
2017-11-01		ND
2017-11-06		ND
2017-12-06		ND
2017-12-06		ND
2017-12-11		0.001000 ppb
2018-01-03		ND
2018-01-03		ND
2018-01-03		ND
2018-02-05		ND
2018-02-07		ND
2018-02-07		ND
2018-03-05		ND
2018-03-07		ND
2018-03-07		ND
2018-04-02		ND
2018-04-04		ND
2018-04-04		ND
2018-05-02		ND
2018-05-02		ND
2018-05-07		ND
2018-06-04		ND
2018-06-06		ND
2018-06-06		ND
2018-07-02		ND
2018-07-11		ND
2018-07-11		ND
2018-08-07		ND
2018-08-13		ND
2018-08-13		ND
2018-08-14		ND
2018-09-04		ND
2018-09-05		ND
2018-09-05		ND
2018-10-01		ND
2018-10-03		ND
2018-10-03		ND
2018-11-05		ND
2018-11-07		ND
2018-11-07		ND
2018-12-03		ND
2018-12-05		ND
2018-12-05		ND
2019-01-02		ND
2019-01-02		ND
2019-01-07		ND
2019-03-04		ND
2019-03-06		ND
2019-03-06		ND
2019-04-01		ND
2019-04-04		ND
2019-04-04		ND
2019-05-01		ND
2019-05-01		ND
2019-05-06		ND
2019-06-05		ND
2019-06-05		ND
2019-07-01		ND
2019-07-03		ND
2019-07-03		ND
2019-08-05		ND
2019-08-07		ND
2019-08-07		ND
2019-09-03		ND
2019-09-04		ND
2019-09-04		ND
2019-10-02		ND
2019-10-07		ND
2019-11-04		ND
2019-11-06		ND
2019-11-06		ND
2019-12-02		ND
2019-12-04		ND
2019-12-04		ND