While economists have tools to provide proxy values for these non-marketed goods and services (e.g. contingent valuation) there application to guide policy decisions can be difficult. As a consequence the short-run marginal cost of water supply for irrigation systems can be very low except for the costs of pumping water through the delivery system. These characteristics of water supply make it likely that there will be a monopoly supplier in any given area, requiring a high degree of managerial and social control.