Irrigation water in Iran is known as the most important and constraining factors of production in the agricultural sector. Historically, the overall of allocation of water has been managed by the government agencies based mostly on the socio-political criteria, instead of economic measure. This type of water management, however has resulted in an inappropriate water allocation in Iran. Water market, as an alternative mechanism for water allocation, can improve water use efficiency through the transfer of water to users who can obtain the highest marginal return from using it. This paper estimates the potential benefits of implementing water market among farmers in the irrigation area of 12500 ha in Saveh region. At first, optimum crop pattern for 24 villages was estimated at absence of water market by using mathematical programming models. Then an aggregate model was used to estimate the effect of water market on farmers' profitability. Results show that exchanges among farmers can increase significantly water use efficiency, particularly during drought. Furthermore, water market as an economic institute, can increase proportionally labor demand or at least reduce negative impact of water scarcity on employment within agriculture sector. Also to broaden the water market the transaction cost had to be declined.