Wastewater planning requires the use of GIS technologies to facilitate the management of data and implementation of sewer models. In particular, the City of San Diego, Metropolitan Wastewater Department is currently using a customized ArcView GIS/data management system to model and analyze its sewer system. An ArcView GIS application (ArcADE) was developed to convert and validate sewer data; process population, land use, and topographic data; and export the data to model format. In addition ArcADE provides add-on utilities including radar rainfall animation, time-series viewing, model simplification, and hydraulic analysis. ArcADE was developed in the ArcView GIS/Avenue environment using Dialog Designer to customize the interface.