A general mixed-integer nonlinear programming model (MINLP) is developed in this study for the design of discontinuous water-reuse systems. The proposed model formulation is believed to be more practical than the available models, in the sense that the unrealistic assumptions adopted in previous works have been removed and, also, the wastewater equalization options can be integrated into the system design. The resulting design specifications include the number and sizes of buffer tanks, the physical configuration of pipeline network, and the operating policies of water flows. The network structure of the water-reuse system can also be strategically manipulated by imposing suitable logic constraints. An illustrative example is presented at the end of this paper to demonstrate the effectiveness of our approach.