Planning for drought and growth-induced water scarcity is a challenge confronting municipal water departments. When water shortages occur, demand management policies and programs are often implemented to encourage water conservation. Due to the public nature of water resources and municipal water delivery systems, cities are particularly concerned about meeting citizens' basic water needs. A city can easily review water billing records to see how much water people use, but how do they know how much water people need? Standards and guidelines have been established for indoor water use (gallons/person/day). The amount of water needed to irrigate outdoor landscapes is more variable, highly contextualized, and harder to determine. This project develops a custom software application that allows water billing data to be integrated with GIS and various other types of municipal databases. Because of the GIS data, a strong spatial component allows for use of parcel, structure, land cover, slope, and soils data. The output shows how actual landscape water use compares with estimated landscape water need, which is used to determine capacity to conserve outdoor water. The software can display spatial patterns and help analyze factors contributing to water use variation. This project will help cities design water conservation programs with the greatest potential for savings.