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EWG's Tap Water Database — 2021 UPDATE

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Bromodichloromethane

Castle Rock

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

 

113

Samples

0

Samples exceeding legal limit (MCL)

96

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015ND10ND
20160.534 ppb2414ND - 2.91 ppb
20171.44 ppb2419ND - 8.12 ppb
20182.44 ppb32320.700 ppb - 9.30 ppb
20191.63 ppb3231ND - 8.20 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 Result
2015-03-24ND
2016-05-030.630 ppb
2016-05-030.540 ppb
2016-05-031.73 ppb
2016-05-030.560 ppb
2016-05-03ND
2016-05-030.720 ppb
2016-05-030.560 ppb
2016-05-030.900 ppb
2016-08-150.630 ppb
2016-08-150.520 ppb
2016-08-150.880 ppb
2016-08-15ND
2016-08-150.690 ppb
2016-08-150.530 ppb
2016-08-15ND
2016-08-15ND
2016-11-142.91 ppb
2016-11-14ND
2016-11-141.02 ppb
2016-11-14ND
2016-11-14ND
2016-11-14ND
2016-11-14ND
2016-11-14ND
2017-05-15ND
2017-05-15ND
2017-05-152.96 ppb
2017-05-15ND
2017-05-15ND
2017-05-150.530 ppb
2017-05-15ND
2017-05-160.610 ppb
2017-08-150.750 ppb
2017-08-150.720 ppb
2017-08-150.520 ppb
2017-08-151.35 ppb
2017-08-150.540 ppb
2017-08-150.640 ppb
2017-08-150.550 ppb
2017-08-230.610 ppb
2017-11-135.12 ppb
2017-11-131.12 ppb
2017-11-138.12 ppb
2017-11-131.32 ppb
2017-11-130.890 ppb
2017-11-136.28 ppb
2017-11-130.970 ppb
2017-11-130.980 ppb
2018-02-212.60 ppb
2018-02-212.70 ppb
2018-02-214.10 ppb
2018-02-210.800 ppb
2018-02-210.700 ppb
2018-02-212.40 ppb
2018-02-211.30 ppb
2018-02-213.30 ppb
2018-05-140.800 ppb
2018-05-140.800 ppb
2018-05-140.800 ppb
2018-05-146.50 ppb
2018-05-146.80 ppb
2018-05-140.800 ppb
2018-05-140.700 ppb
2018-05-145.60 ppb
2018-08-072.10 ppb
2018-08-079.30 ppb
2018-08-074.80 ppb
2018-08-071.80 ppb
2018-08-071.000 ppb
2018-08-071.90 ppb
2018-08-071.70 ppb
2018-08-072.30 ppb
2018-11-273.50 ppb
2018-11-270.800 ppb
2018-11-272.10 ppb
2018-11-270.700 ppb
2018-11-270.800 ppb
2018-11-270.700 ppb
2018-11-270.800 ppb
2018-11-273.00 ppb
2019-02-192.00 ppb
2019-02-191.20 ppb
2019-02-192.20 ppb
2019-02-190.700 ppb
2019-02-190.700 ppb
2019-02-191.10 ppb
2019-02-191.40 ppb
2019-02-192.20 ppb
2019-05-07ND
2019-05-070.900 ppb
2019-05-078.20 ppb
2019-05-070.600 ppb
2019-05-080.800 ppb
2019-05-080.700 ppb
2019-05-080.600 ppb
2019-05-080.900 ppb
2019-08-075.10 ppb
2019-08-070.700 ppb
2019-08-074.20 ppb
2019-08-072.40 ppb
2019-08-071.20 ppb
2019-08-070.800 ppb
2019-08-072.20 ppb
2019-08-072.30 ppb
2019-11-120.600 ppb
2019-11-120.900 ppb
2019-11-123.10 ppb
2019-11-120.900 ppb
2019-11-120.900 ppb
2019-11-120.800 ppb
2019-11-120.900 ppb
2019-11-120.900 ppb