EWG's Tap Water Database — 2021 UPDATE



Entranosa Water and Wastewater Co-op

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
20151.08 ppb220.650 ppb - 1.50 ppb
20160.915 ppb220.530 ppb - 1.30 ppb
20170.690 ppb220.430 ppb - 0.950 ppb
20180.715 ppb220.230 ppb - 1.20 ppb
20190.300 ppb21ND - 0.600 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
2015-08-1220150232431.50 ppb
2015-08-1220150232420.650 ppb
2016-08-0520160225481.30 ppb
2016-08-0520160225490.530 ppb
2017-08-1520170235830.950 ppb
2017-08-1520170235820.430 ppb
2018-08-0920180222780.230 ppb
2018-08-0920180222791.20 ppb
2019-08-1920190231570.600 ppb