The article presents the development and condition of the sewage system in the cities and municipalities of Wielkopolska Voivodeship in the years 1999-2015. The data from Statistical Yearbook from Central Statistical Office – Environment Protection and Local Data Bank, and from National Programme for Municipal Waste Water Treatment implementation reports constituted the basis for the analysis. Over the last 16 years, the system of sewage management in municipalities has steadily improved. The study showed a heterogeneous state of development of the sewage network and wastewater treatment plant (WWTP), different growth of network, as well as variability in the share of the population using the sewage network. In last years the number of people who use the WWTP and sewage network has clearly increased. Moreover, the tendency for increasing amount of sewage treated in high performance technologies is observed. Unfortunately, this does not translate into significant improvements in the water quality in the region. Despite the clear improvement of the state of the sewage economy, it was not possible to fully achieve the assumptions arising from the National Programme for Municipal Waste Water Treatment, both in the voivodship and in the country.