The topic of this graduation thesis is conceptual design of sewer system - for the settlements of Lovranska Draga, Liganj and Tuliševica in municipality of Lovran. In given settlements there is no constructed drainage system of sanitary waste water, which is considered as a main issue in the area. Thesis is made using available resources; base map (1:5000), digital ortophoto map (1:5000) as well as Spatial Planning documentation of municipality of Lovran. According to the Spatial Plan of municipality of Lovran, two drainage of sanitary waste water systems were designed in this thesis; 1) Drainage system for Lovranska Draga settlement, and 2) Drainage system for Liganj-Tuliševica settlements. In drainage system of Lovranska Draga wastewater treatment will be performed with newly constructed wetland, while system of Liganj-Tuliševica is planned to be connected to the existing sewer system of municipality of Lovran which already has its wastewater treatment plant. Thesis contains technical description of designed drainage systems, hydraulic designs for each sewer system, pump station designs, static analysis of pipes and estimation of construction cost. Graphical part contains situations plans of networks for the both systems as well as longitudinal profiles of drainage collectors. Also in thesis details of manholes, cascade windows, pump stations and characteristic of the trench for the installation of sewer pipes are given. Thesis was made using software Urbano Canalis 9.0, which is developed by StudioARS company, and is also used for designs and drawing.