Agriculture is the main water-using sector in Southern European Countries, such as Spain and Italy. Innovative institutional solutions for reducing water use or increasing its efficiency are pursued by recent legislation concerning water, in particular by the Water Framework Directive (WFD). Even if not explicitly considered by the directive, water markets may be seen as a kind of instrument responding to the guiding principles of the upcoming water regulation. The issue of water markets is very much debated in the water economics literature and particularly in the agricultural water literature. Water markets refer to a mechanism of water allocation based on the exchange of rights on water use. Water markets are proposed and supported by ec...