The aim of the research was to get the expertise, how location of wastewater treatment plant to basin of sewage system influences the temperature of inflowing wastewater. The analysis included four sewage systems, which are different for the sake of length of transit canal between treatment plant and residential buildings, in which domestic sewage was produced. In analysed systems sewage flew into the treatment plants with hydraulic capacity range from 100 to 300 m3•d-1, and with population equivalent less than 2000. Measurements of temperature of air and wastewater outflowing from sewage system, in analysed year 2012, were conducted continuously, with 1 hour interval, with use resistance sensors connected with data recorder. The research showed, that the distance of treatment plant to basin of sewage system has a significant impact on wastewater temperature outflowing from sewage system. In winter period mean daily wastewater temperature outflowing from transit manifolds with length from 300 to 600 m was lower even about 3oC, but in summer period up to 8oC, in comparison to transit manifolds with length less than 10 m. Moreover, it was proved that, apart from length of transit manifold, also intensity of wastewater flow has a significant impact on wastewater temperature flowing into the treatment plant. With increase of intensity of wastewater flow about 100%, its temperature can increase in winter period about o 1oC, and about 3oC in summer period. In case of sewage systems ended with long transit manifold, the duration time of optimal sewage temperature in terms of biogenic compounds removal is unfavourable reduced, and at the same time the duration time of wastewater temperature unfavourable for its biological treatment is extended.