This article deals with the distribution of financial resources allocated to the basic sanitary systems in the Rio de Janeiro metropolitan area during the 1975-1991 period. The study analyzes the investments allocated by the local utility company, known as Cedae, using a spatial model produced especially for this research. The model was produced using information from the national demographic census of 1980, the only one developed within the study period. The recent changes as observed are explained on the basis of their relationship to the spatial and political contexts in the metropolis and the country, as well as from the organization of the services themselves. The paper adds important arguments to the discussion over the restructuring of metropolitan areas and urban public policies. The spatial and social distribution of resources observed during the period differed from the preexisting pattern, yet although there was a substantial democratization in the allocation of public resources, the pattern was not subverted.