Using conventional methods and tools for determining detailed zonal water balances and performance indicators involves considerable efforts in manual data collection and processing. Hence, water balances mostly are determined for a whole network only. Unmetered components are often neglected or based on rough estimates. This article presents an approach to the automated determination of zonal water balances and its implementation as a software tool. The approach is demonstrated for the practical case of the Pforzheim water utility (Stadtwerke Pforzheim GmbH & Co. KG).