A conceptual solution of the water supply system for the city of Cres is shown in this master's thesis. First part of this master's thesis is about general features of analyzed area and calculation of relevant quantities of water for consumers, hydraulic calculation of water supply system and calculation of reservoirs and pump stations. The system is calculated for two models of water inflow into the reservoir. The models are gravitational model of water inflow and water inflow with the help of pumping. Calculations were performed for three dispositions of the reservoir with the gravitational inflow of water into the reservoir and three dispositions of the pumps in the case of inflow of water by means of pumping. After calculations, all consumer needs for water were met. In addition to consumers, the fire load for fires within the population zone and the industrial zone was also calculated. The second part includes work in the Bentley WaterCAD computer program in which all six versions of the water supply system were installed and a hydraulic calculation was performed with different scenarios with and without fire.The third part of this thesis includes the implementation of the hydraulic calculation into the Urbano Hydra computer program in which a longitudinal pipeline profile and a characteristic cross section profile are also obtained. The pipeline was laid along the roads. The calculation was performed for cast iron (ductile) pipes, and in several variants for PVC pipes where the comparison of pressures was performed using different pipe materials in the water supply system.