EWG's Tap Water Database — 2021 UPDATE



Borough of Atglen

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
20162.60 ppb221.60 ppb - 3.60 ppb
20172.41 ppb880.600 ppb - 5.90 ppb
20184.56 ppb881.30 ppb - 13.0 ppb
20193.50 ppb87ND - 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 Lab ID Result
2016-12-19153661933.60 ppb
2016-12-19153661991.60 ppb
2017-02-14156500380.600 ppb
2017-02-14156500440.600 ppb
2017-05-15160885244.00 ppb
2017-05-15160885291.90 ppb
2017-08-14167213585.90 ppb
2017-08-14167213644.60 ppb
2017-11-28171564980.700 ppb
2017-11-28171564921.000 ppb
2018-02-138022191-021.30 ppb
2018-02-138022191-013.30 ppb
2018-05-158051853-013.80 ppb
2018-05-158051853-022.10 ppb
2018-08-148081652-01RE13.0 ppb
2018-08-148081652-022.40 ppb
2018-11-138111380-018.00 ppb
2018-11-138111380-022.60 ppb
2019-02-139021440-012.40 ppb
2019-05-149051107-015.80 ppb
2019-05-149051107-022.50 ppb
2019-08-139082120-018.20 ppb
2019-08-139082120-027.40 ppb
2019-11-129112093-020.600 ppb
2019-11-129112093-011.10 ppb