In this study, the theory of equilibrium water prices is constructed and practiced based on previous research on cooperative game technology and the water price system. The equilibrium water price utilized in this study emphasized solving the unbalanced and unsustainable water supply system, including the reclaimed water resources and the current water price used in numerous Chinese cities. Safety, affordability, and sustainability become the key factors of the equilibrium water price system, which is operated and analyzed in a typical city in southeastern China. The cooperative game model of equilibrium water price is solved by game technology, considering various factors such as the price strategy, the water supply quantity, and the local water demand. The practical application shows that the theoretical system can effectively solve the problem of water price formation mechanisms after the unified allocation of different types of water resources. It not only enhances the enthusiasm and initiative of the public in the utilization of reclaimed water, but also plays an important role in the rational utilization of multiple water resources for different purposes by introducing a reasonable water price ratio and local water resource allocation.