Past efforts at assisting less developed countries to develop low-cost water and sewage treatment methods have not been too successful. The technology transfers have usually been incompatible with in-country resources of manpower and materials. In 1973, aid. sponsored a three-year project at the university of Oklahoma to develop a predictive model for use in selecting water treatment sites and methods compatible with the needs and resources of developing countries. The project produced a predictive model that uses cost and demand analysis. It also produced a data collection system, computer and manual user guides, and an analytic kit that can be used in less developed countries. The analytic field kit was also tested for its capacity to monitor water and wastewater treatment processes. A need exists for a prioritizing model to assist in-country programs in establishing orderly construction of facilities. The use of the predictive model is expected to be expanded as information concerning its capacities is disseminated.