Scattered settlements in Slovenia are the main reason why the connection of houses to public water supply and sewage system is often difficult. As a result, many houses do not have regulated sewerage system and the occupants have to arrange the cleaning of the waste waters themselves. This thesis was made to compare cleaning waste-waters with mechanical-biological wastewater treatment and treatment plant. The case was made on the specific example of one one-dwelling house. The purpose of this comparison is to determine whether is the plant cleaning machine more optimal than the mechanical-biological cleaning machine in terms of water purification, cost, durability, layout and preparation of the terrain. The thesis is based upon the existing dwelling-house and an already existing ProSigma wastewater treatment.