Untreated stormwater runoff can be an important source of pollutants affecting urban surface waters. For example, in Berlin each year 78% or 54 million m³ of stormwater are discharged mostly untreated into receiving surface waters. Beside “classic” stormwater pollutants (e.g. suspended solids, COD, phosphorous or heavy metals), trace organic substances such as biocides, plasticizers, flame retardants and traffic related micropollutants (e.g. vulcanizing accelerators originating from tire wear or combustion by-products such as PAHs) started to come into focus in recent years (Zgheib et al. 2012, Gasperi et al. 2014). To evaluate for the first time city-wide annual loads of these trace organic substances entering urban surface waters through stormwater discharge, an event-based, one-year monitoring program was set up in the city of Berlin.