In this paper, coordinating technique for the multi-layer model predictive control (MPC) of complex water network is proposed. A multi-layer topology structure resulting from a functional decomposition of water network is briefly presented. Inside each layer, a MPC based controller is used. Between the related two layers, a multi-layer coordinating mechanism is provided to generate control strategies which consider objectives and time scales of both layers. Optimal Path Method (OPM) is used to estimate aggregated water price for the whole layer. The case study is the Catalunya Regional Water Network. Simulation results based on an aggregate model of this network are provided.