To consider the long-term management of the water resources used to produce drinking water in Gironde (south-west of France), the SMEGREG (public watershed establishment in charge of deep aquifers in Gironde, France) and INRAE (French public research institute) are leading a collaboration which, in order to forecast changes in the level of water losses, focuses on the impact of demography and urbanization on the assets of drinking water supply networks (DWSN). Analyses are carried out at the scales of the Gironde county and the Bordeaux metropolitan area (BM), based on demographic and geographic databases, French observatory of water services database and the GIS of the BM's DWSN. The first results obtained show that an increase in the population served by a DWSN translates into a much smaller increase in the length of pipes and a comparable increase in the number of service connections. They also show that the higher the urban density of an area, the lower the impact of population growth on the increasing of pipes length.