Small hydro power systems (SHPSs) are increasingly installed in water distribution systems (WDSs). With only minor adaptations in a WDS, pressure surplus can be utilised. In such systems, a water surplus is also often available. In this work, water consumption data of a real Alpine WDS over one year are used as an input for an Epanet2 long-term simulation model to assess such a SHPS. In addition, the combinations of pressure and water surplus devices in a WDS are investigated. For such a specific investigated case, the yearly profit of 1750 € for a single SHPS could be increased to 3550 € when combining two interacting devices. Further, necessary and upcoming rehabilitation measures are investigated concerning their positive impact on the energy production potential and how additional costs (e.g., higher diameters (200 mm instead of 125 mm)) can be compensated by additional profits from energy production (maximum 5250 € per year).