The European Water Framework Directive of 1991, which aim is to limit the discharge of urban rainwater, constrains the cities to improve their sewerage system in order to face such events. The combined sewer overflows are a very sensitive theme in Berlin because of the city’s drink water supply system. The Integrated Sewage Management project, materialized within the Berlin Water Competence Center, aims to optimize the network thanks to hydraulic and pollution modelling. The first step of this study is to model a pilot catchment’s area, thanks to the Hydroworks DM software. Beyond the network constitution, a measurement campaign is realized to calibrate the model, for hydraulic as well as for pollution processes. This has to be done for both dry and rain weather. A first calibration is made possible by the results of dry weather measurements. The analysis of rain weather measurements will allow the validation of the model to be done, and its transposition to the other Berlin catchment’s areas.