This paper provides a summary of an application of GIS for urban water systems in Can Tho city, Vietnam. The system aimed at providing the city?s agencies a spatial presentation and tool for planning and management. A large amount of secondary data and information of the city urban water systems has been collected from the related city's agencies. There was a need to ensure that these information be made available in a systematic and useful form that can be easily accessed and could inform the city?s agencies in planning and development decision making. For this purpose, the data and information were summarized into a GIS database, and visualized in the forms of a Map Book and a WebGIS. These products provide simple and effective ways to present complex data and relationships, and to enable a more intuitive and rapid data interpretation than data embedded in large reports or spreadsheets. Currently the Map Book and the WebGIS for Can Tho city contain 25 maps, presenting information across four main themes: (i) social economics, (ii) surface and ground water quality and quantity, (iii) water supply and sanitation infrastructures, current and planned, and (iv) spatial analysis of households? access and satisfaction of current water services. The Map Book and the WebGIS have generated significant interests from local departments/agencies, as they provide them with a better understanding on key issues, a useful reference for planning and development decisions, and an effective platform for collaboration between agencies in managing the city urban water systems and environment.