EWG's Tap Water Database — 2019 UPDATE



Peu/ministerial Hills

Bromoform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromoform 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
20120.700 ppb110.700 ppb
20130.500 ppb110.500 ppb
20140.600 ppb110.600 ppb
20160.700 ppb220.600 ppb - 0.800 ppb
20170.700 ppb110.700 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.5 ppb

The EWG Health Guideline of 0.5 ppb for bromoform 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
2012-10-251210-00822-0010.700 ppb
2013-10-101310-00391-0010.500 ppb
2014-10-131410-00854-0010.600 ppb
2016-07-141607-01485-0010.800 ppb
2016-10-241610-02385-0010.600 ppb
2017-12-041712-00335-0010.700 ppb