The task of this work is to present the conceptual design of the drainage system of the Municipality of Mrkopalj, e.g. settlements Mrkopalj and Sunger. In addition, the thesis gives an insight into the scope and quantity of the works and the amount of financial resources required for the system performance. In the introduction part of the thesis are given general information on sewerage, e.g. the types, functions and parts of sewage systems. Also in the introduction part are presented general data on the wastewater treatment plant typical for a small village settlement. In the main part of the thesis are given technical description, hydraulic and static calculation of the collector, pumping station calculation, graphical plans and approximate cost for all the necessary works for the performance of the drainage system for settlements of Mrkopalj and Sunger. In the final part of the thesis are given conclusion, and the literature used in this thesis. Proposed design solution given in this thesis consists of a separate drainage system for sanitary wastewaters. Vargon plastic collectors and 3 pumping stations were used to enable unimpeded drainage of sanitary wastewaters to wastewater treatment plant.