The subject of this thesis are conceptual solutins for drainage and treatment of wastewater in the villages Božakovo, Želebej and Rakovec situated in the Municipality of Metlika. The villages are located in the immediate vicinity of the bathing river Kolpa and protected areas Natura 2000, which is an additional reason to address the problem of wastewater. The preliminary chapter covers legislation applicable to the drainage and treatment of wastewater. The first part describes the natural and demographic characteristics of the area, depicting the villages in question. In the following section general caracteristics of sewage systems are presented. The second, practical part of the thesis, shows design I, which considers an individual WWTP for each village. In design II villages Božakovo and Želebej are connected ta a common WWTP. The methods of planning, dimensioning and realization are presented for individual designs. The last part focuses on the calculated costs of construction, operation and maintenance and gives the financial comparison of the two solutions.