||Computer-based mathematical models for urban water resources planning, management and design are widely used by engineers and planners in both the public and private sectors. In the United States, the majority of the users are in the private (consulting) sector, yet most of the major model development is done by, or under the sponsorship of, a number of Federal agencies. The Federal government, however, has no effective, centralized system to catalog, maintain, distribute or support these models, and it is frequently difficult for even experienced users to determine what is available, much less make informed judgements about suitability, either from a technical or administrative (cost, availability of documentation, training, user assistance, etc.) standpoint. This paper briefly describes how various Federal and non-Federal agencies address this problem, including the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Geological Survey, the U.S. Department of Agriculture, the National Weather Service and several commercial vendors. Emphasis is on describing how these groups function, and references are provided.