This article deals with the issues of data processing, storage, analysis and optimisation of urban water supply networks using information systems. The water supply network of Aleksotas–Narsiečiai–Mastaičiai–Garliava and surrounding areas is analysed. The absence of hydraulic modelling information system hampers the ability to deal promptly with day-to-day problems, plan repairs and reconstructions of water supply networks, or to analyse further developments and their impact on the system. For the first time, the hydraulic model of the system is being developed for the territory of Kaunas City Municipality in order to simulate the real operation of the system with minimal deviations. Based on the results of the hydraulic model analysis, recommendations are provided on how to rationally adjust the operation of the analysed water supply system and how to develop the drinking water network in a sustainable and coherent way in the future.