The demand for clean water as a resource is increasing. For this reason the EU Water Framework Directive strives for improvement of the ecological and chemical condition of all waters. A river basin management plan is to be set up considering various aspects. Especially the discharge of wastewater treatment plants as well as the discharge of wastewater from the sewer system during a heavy rain event can have a great impact on the water quality. The first step to prove the status of waters is to display the emissions in detail.