This chapter deals with the setup of the simulation model of pressure zone Holsterhausen. This model consists of two parts: The relevant processes within the waterworks Dorsten-Holsterhausen and the distribution network for drinking water. These parts are connected by the drinking water pumps. To consider the huge distribution network within the simulation model an abstraction is required, leading to arregated pipes and tanks. The final simulation model is calibrated. Calibration is made separately for single network elements like pumps and valves and for the aggregated network. The calibration of e.g. pumps can be done automatically, whereas the calibration of the network is largely a manual process. Finally, some typical simulation results are discussed. The achieved accuracy is appropriate for practical application and the further optimization process.