Introduction: The Office of Arid Lands Studies (OALS), the Water Resources Research Center (WRRC), of the University of Arizona, and the Arizona Water Commission (AWC) have developed a generalized data storage and retrieval system on the DEC-10 computer system at the University of Arizona for systematic reporting of water information (quality and quantity) within the State of Arizona. The objective of the on-line system is to expand the AWC's efficiency in answering routine questions regarding Arizona's water resources easily and on short notice through remote terminal access to hydrologic information. Currently, two files reside on AWIS whereby water-related information can be extracted for the entire State on either quarter- township basis or regionally by drainage basin. AWC is given authority to "collect and investigate information upon and prepare and devise means and plans for the development, conservation, and utilization of all waterways, watersheds, subterranean waters, groundwater basins and water resources in the State. . ." To this end, AWC is developing a State Water Plan, and the data residing on the two files in AWLS are part of the Plan's first phase--an inventory of the resource, current uses and associated problems as presented in Arizona Water Commission Report "Arizona State Water Plan, Inventory of Resources and Uses, Phase I, July, 1975."