The U.S. EPA’s Wellhead Analytic Element Model, WhAEM2000 for Windows (98/NT/2K/XP), is a groundwater geohydrology computer program. WhAEM2000 is a public domain, ground-water flow model designed to facilitate capture zone delineation and protection area mapping in support of the State’s Wellhead Protection Programs (WHPP) and Source Water Assessment Planning (SWAP) for public water supplies in the United States. WhAEM2000 provides an interactive computer environment for design of protection areas based on radius methods, well in uniform flow solutions, and geohydrologic modeling methods. Protection areas are designed and overlaid upon US Geological Survey Digital Line Graph (DLG) or other electronic base maps. Base maps for a project can be selected from a graphical index map for the State. Geohydrologic modeling for steady pumping wells, including the influence of hydrological boundaries, such as rivers, recharge, and no-flow contacts, is accomplished using the analytic element method.