The graduate thesis presents the technical solution for the reconstruction of the existing water supply system and the construction of a future water supply system in the area of the city of Rijeka, in the settlement of Draga in Brig Street. The existing facilities in the area in question do not have satisfactory conditions for connection to the public supply infrastructure, that is, no public drainage system has been built, and water is supplied to the facilities via unacceptably long domestic water connections. The existing water supply line consists of galvanized pipes with a diameter of DN 50 mm. The technical solution presented envisages replacing the existing pipes with new DN 100 mm ductile pipes. The pipeline is connected to the south-west of the existing water supply pipeline made of DN 125 mm ductile iron pipes and is supplied via the Brig reduction station at an altitude of 153 meters above sea level (inlet 8.8 bar and outlet 5.6 bar). The total length of the new water supply branches is 282 meters, of which 233 meters are to be built with DN 100 ductile pipes, and other 49 meters with galvanized DN 50 mm pipes. In addition to the water supply sections, a 33 m long sanitary collector will also be built, which will connect to the south-west of the existing collector made of DN 200 mm ductile iron pipes. Appropriate hydraulic calculations were carried out for the planning of the planned pipelines (using EPANET and Excel).