EWG's Tap Water Database — 2021 UPDATE



Mars Borough Water Works

1,2-Dichloroethylene, a neurotoxic solvent, exists in two different forms: trans-1,2-dichloroethylene and cis-1,2-dichloroethylene. A mixture of the two forms is used to manufacture other solvents and chemical products.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20142.50 ppb112.50 ppb
20152.20 ppb112.20 ppb
20163.00 ppb113.00 ppb
20172.20 ppb112.20 ppb
20182.30 ppb112.30 ppb
20192.56 ppb112.56 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EPA Maximum Contaminant
Level (MCL) 70 ppb

The legal limit for cis-1,2-dichloroethylene, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1980s.

ppb = parts per billion

All test results

Date Lab ID Result
2014-08-0514080920-0012.50 ppb
2015-08-05132026862.20 ppb
2016-11-14153035063.00 ppb
2017-09-25168097562.20 ppb
2018-07-1718G1584-012.30 ppb
2019-08-1619H2178-012.56 ppb