1n February 1994 the Council of Australian Governments (COAG) agreed to a number of significant reforms of the water industry. One of the most important was to "implement comprehensive systems of water allocations or entitlements backed by separation of water property rights from the land title and clear specification of entitlements in terms of ownership, volume, reliability. transferability and, if appropriate, quality. In relation to trading in water allocations or entitlements COAG also noted that where cross-border trading is possible, that the trading arrangements be consistent and facilitate cross-border sales where this is socially, physically and ecologically possible. The purpose of this paper is to report on the first part of a wider research program evaluating alternative water property rights structures and trade within and between NSW and Victoria. Regional linear programming models are used to determine supply and demand functions for irrigation water in nine irrigated regions in southern NSW. The results of this analysis will subsequently be incorporated into a spatial equilibrium model being co-operatively developed by NSW and Victoria