The water distribution problem of the Mexican Valley is modeled as a three-person no uncooperative Game in which agriculture, industry, and domestic water users are the players and the total water Amounts supplied to the users are the payoff functions. The equilibrium is determined by solving a nonlinear optimization problem, which can be derived based on the Kuhn-Tucker necessary Conditions. All constraints are linear and the objective function is quadratic, so standard solution Algorithm and software can be used.