Ground water is an excellent resource due to its quality and availability. In the United States it is available at almost any location in quantities large enough to provide for domestic needs and over one-third of the Country is underlain by aquifers capable of yielding 100,000 gallons or more daily on a sustained basis. This expansive nature of ground water is paradoxical in terms of its ability to meet water supply requirements over long periods of time. A ground-water research strategy is presented which divides research considerations into three areas based on the types of processes that will effect pollutant movement in the subsurface: (1) hydrologic; (2) abiotic; and (3) biotic processes.