Sanitary landfills are common facilities for waste disposal. The process of designating a location as a landfill requires extensive studies of biogeochemical and hydrologic characteristics of all potential sites. This process demands a considerable amount of empirical inputs, expert opinions, and heuristic rules. A site selection process can be modeled only by incorporating the available empirical and expert rules into our decision making process. This task can be accomplished in the framework of knowledge‐based expert systems. A prototype expert system for site selection is presented. The rules are based on U.S. EPA documents for ranking of uncontrolled hazardous waste sites for remedial actions. They include rules concerning ground water routes, local climate, waste characteristics, planned features of the proposed landfill facility, and targets at risk. The above model is programmed with the aid of Insight 2+, which is a microcomputer shell progra