EWG's Tap Water Database — 2019 UPDATE



St. Louis City

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.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20122.91 ppb26261.37 ppb - 5.39 ppb
20132.11 ppb14140.790 ppb - 9.69 ppb
20141.14 ppb14140.800 ppb - 1.67 ppb
20151.98 ppb14141.16 ppb - 2.83 ppb
20163.17 ppb991.53 ppb - 5.45 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 Lab ID Result
2012-03-06AB685292.97 ppb
2012-03-06AB685405.26 ppb
2012-03-06AB685394.29 ppb
2012-03-06AB685382.82 ppb
2012-03-06AB685373.88 ppb
2012-03-06AB685364.73 ppb
2012-03-06AB685354.44 ppb
2012-03-06AB685344.55 ppb
2012-03-06AB685335.05 ppb
2012-03-06AB685323.07 ppb
2012-03-06AB685312.68 ppb
2012-03-06AB685305.39 ppb
2012-06-11AB763491.79 ppb
2012-06-11AB763501.87 ppb
2012-06-11AB763511.48 ppb
2012-06-11AB763522.08 ppb
2012-06-11AB763531.62 ppb
2012-06-11AB763481.84 ppb
2012-06-11AB763471.91 ppb
2012-06-11AB763461.84 ppb
2012-06-11AB763451.37 ppb
2012-06-11AB763441.48 ppb
2012-06-11AB763431.78 ppb
2012-06-11AB763421.66 ppb
2012-06-28HBCB062812M5243.10 ppb
2012-06-28CRCW062812M5242.60 ppb
2013-06-11AC024481.91 ppb
2013-06-11AC024471.22 ppb
2013-06-11AC024461.20 ppb
2013-06-11AC024451.30 ppb
2013-06-11AC024441.35 ppb
2013-06-11AC024431.35 ppb
2013-06-11AC024421.38 ppb
2013-06-11AC024411.33 ppb
2013-06-11AC024400.790 ppb
2013-06-11AC024390.920 ppb
2013-06-11AC024381.08 ppb
2013-06-11AC024371.09 ppb
2013-10-22HBCB102213M5249.69 ppb
2013-10-22CRCW102213M5244.96 ppb
2014-05-28AC261300.800 ppb
2014-05-28AC261291.06 ppb
2014-05-28AC261281.28 ppb
2014-05-28AC261270.890 ppb
2014-05-28AC261260.900 ppb
2014-05-28AC261251.11 ppb
2014-05-28AC261241.05 ppb
2014-05-28AC261230.880 ppb
2014-05-28AC261141.06 ppb
2014-05-28AC261151.58 ppb
2014-05-28AC261191.67 ppb
2014-05-28AC261200.860 ppb
2014-05-28AC261211.58 ppb
2014-05-28AC261221.21 ppb
2015-03-17AC446591.72 ppb
2015-03-17AC446491.16 ppb
2015-03-17AC446501.80 ppb
2015-03-17AC446512.08 ppb
2015-03-17AC446571.82 ppb
2015-03-17AC446482.05 ppb
2015-03-17AC446521.48 ppb
2015-03-17AC446581.40 ppb
2015-03-17AC446561.88 ppb
2015-03-17AC446552.35 ppb
2015-03-17AC446542.58 ppb
2015-03-17AC446532.83 ppb
2015-06-01AC473901.79 ppb
2015-06-01AC473912.71 ppb
2016-03-08AC688381.63 ppb
2016-03-08AC688422.40 ppb
2016-03-08AC688375.45 ppb
2016-03-08AC688394.52 ppb
2016-03-08AC688404.53 ppb
2016-03-08AC688414.66 ppb
2016-06-06AC758671.53 ppb
2016-06-06AC775101.89 ppb
2016-06-06AC758661.96 ppb