The diploma thesis discusses the area of wastewater drainage. In the theoretical part of the thesis I described the factors of water pollution, legislation in this field, elements of sewerage systems and wastewater treatment options. In the analytical part of diploma thesis I analyzed the natural and social features of the Kokra basin in the municipalities of Jezersko and Preddvor and explained the impact of natural and anthropogenic factors on the environment. In case of village Mače I made a variant conceptual design of sewerage system with practical solution for reducing the pollution of surface waters from the drainage area. The first option predicts the construction of an independent sewage system with small treatment plant, while the second option consists of the sewerage system by connecting to an existing sewerage system of Preddvor. For each option I calculated total costs, based on the inventory work, operating and maintenance costs. For the subject area I determined annual intake of nitrogen and phosphorus into the environment, contributed by various sources: wastewater from households, hardened surfaces, forests, fields, roads and water treatment plants. Both elements have the excessive concentration significantly negative impact on growth in the amount of nutrients in the stream and associated eutrophication.