Slovenian and European legislation seeks to ensure that all wastewater is properly cleaned, before it is released into nature. It is for this reason, that more agglomerations are being introduced, where wastewater needs to be properly drained off and treated. In the master's thesis, we made the conceptual design for the sewage system in the towns Fikšinci and Gerlinci. After the analysis of the surface, we predicted three possible solutions for drainage and treatment of sanitary wastewater in a given area. All variants were designed in a combination of gravity pipes and pressure pipes with a pumping station. The first variant includes Fikšinci and partly Gerlinci with treatment plant in Fikšinci. The second variant occupies the same area, but discharge the waste water to the central treatment plant in Cankova. The third variant only includes Fikšinci. The technical suitability of the sewer system was checked by calculating the hydraulic conditions in the pipelines. In the end, we made a cost analysis of individual variants and calculated the investment costs with the help of a specification of works. We also evaluated the maintenance costs of individual variants and using the total costs compared the individual variants for the period of 50 years - the lifespan of the investment. We found that variant 3 has the lowest investment costs and the highest maintenance costs. The total cost for a period of 50 years have shown that variant 3 is the most economically viable solution. The best technological solution would be the variant 2, but it would also be the most expensive. In this variant, the wastewater is drained to a wastewater treatment plant in Cankova, which has an additional tertiary level of wastewater treatment.