The city of Buenos Aires, the capital town of Argentina, is located besides De la Plata river, and is surrounded by a continuum of built areas, the so-called Greater Buenos Aires. The present situation of sewerage system is described and analysed taking into account: distance from Buenos Aires city, geographic location, socio-economic level, wastewater treatment technologies, management and regulatory agencies. The existence of a sewerage system does not mean automatically wastewater treatment, as frequently in Latin America. The water quality of wastewater receiving bodies is a matter of increasing concern, since large quantity of pollutants is daily discharged.