In 1991, the Compagnie Generale des Eaux Centre Regional de Lyon set up a computerized network mapping and management system for all communities within the Lyons conglomeration it manages. The main objectives of the mapping system selected were to: improve the quality of available data on the network, particularly during the constitution of the database (entry of existing documents into the system) and to facilitate subsequent updating; include the management of all technical data on the network (leaks, work done, renovation, etc.) into a single mapping system; make this data more easily available to all people involved in operation (the design office and decentralized agencies); provide aid with operation (management of cuts in water supply, customers to whom water is critical, etc.) and with the programming of replacement of pipes and structures; use the computerized storage and printing facilities to simplify the management and circulation of drawings and other documents concerning equipment within the network. Discussion concerning the system, mapping organization, integration into operational practices, assessment is contained in this paper.