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EWG's Tap Water Database — 2021 UPDATE

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Dibromochloromethane

Castle Rock

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

 

113

Samples

0

Samples exceeding legal limit (MCL)

68

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015ND10ND
20160.665 ppb249ND - 5.81 ppb
20171.93 ppb2410ND - 13.6 ppb
20183.92 ppb3222ND - 14.1 ppb
20192.02 ppb3227ND - 10.2 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
2015-03-24ND
2016-05-031.27 ppb
2016-05-03ND
2016-05-032.94 ppb
2016-05-030.530 ppb
2016-05-03ND
2016-05-030.610 ppb
2016-05-03ND
2016-05-031.25 ppb
2016-08-150.650 ppb
2016-08-15ND
2016-08-151.15 ppb
2016-08-15ND
2016-08-15ND
2016-08-15ND
2016-08-15ND
2016-08-15ND
2016-11-145.81 ppb
2016-11-14ND
2016-11-141.75 ppb
2016-11-14ND
2016-11-14ND
2016-11-14ND
2016-11-14ND
2016-11-14ND
2017-05-15ND
2017-05-15ND
2017-05-154.18 ppb
2017-05-15ND
2017-05-15ND
2017-05-15ND
2017-05-15ND
2017-05-16ND
2017-08-15ND
2017-08-15ND
2017-08-15ND
2017-08-151.94 ppb
2017-08-15ND
2017-08-15ND
2017-08-15ND
2017-08-23ND
2017-11-1310.9 ppb
2017-11-130.610 ppb
2017-11-1313.6 ppb
2017-11-131.59 ppb
2017-11-131.000 ppb
2017-11-1310.9 ppb
2017-11-130.750 ppb
2017-11-130.780 ppb
2018-02-216.80 ppb
2018-02-217.30 ppb
2018-02-219.60 ppb
2018-02-210.700 ppb
2018-02-21ND
2018-02-214.90 ppb
2018-02-212.10 ppb
2018-02-217.90 ppb
2018-05-14ND
2018-05-14ND
2018-05-14ND
2018-05-1410.7 ppb
2018-05-1411.2 ppb
2018-05-14ND
2018-05-14ND
2018-05-149.50 ppb
2018-08-073.20 ppb
2018-08-0714.1 ppb
2018-08-077.00 ppb
2018-08-072.20 ppb
2018-08-070.600 ppb
2018-08-072.30 ppb
2018-08-072.20 ppb
2018-08-073.10 ppb
2018-11-278.20 ppb
2018-11-27ND
2018-11-274.30 ppb
2018-11-27ND
2018-11-270.500 ppb
2018-11-27ND
2018-11-27ND
2018-11-277.00 ppb
2019-02-194.60 ppb
2019-02-191.10 ppb
2019-02-195.20 ppb
2019-02-190.600 ppb
2019-02-19ND
2019-02-191.000 ppb
2019-02-191.40 ppb
2019-02-194.70 ppb
2019-05-07ND
2019-05-070.800 ppb
2019-05-0710.2 ppb
2019-05-070.500 ppb
2019-05-08ND
2019-05-080.600 ppb
2019-05-08ND
2019-05-080.900 ppb
2019-08-077.90 ppb
2019-08-070.600 ppb
2019-08-075.50 ppb
2019-08-072.60 ppb
2019-08-071.20 ppb
2019-08-070.600 ppb
2019-08-072.20 ppb
2019-08-072.80 ppb
2019-11-12ND
2019-11-120.800 ppb
2019-11-125.60 ppb
2019-11-120.600 ppb
2019-11-120.600 ppb
2019-11-120.600 ppb
2019-11-120.800 ppb
2019-11-120.600 ppb