Sustainable urban water infrastructure planning has become one of the major concerns when facing the growing urbanization pace and challenges in China. The paper aims to integrate the modern decision support tools in urban water supply system (WSS) planning and programing. A case study of Ningbo, China is presented to assess the cost-effectiveness and sustainability of the selected WSS. A multi-criteria sustainability analysis (MCSA) approach is adopted for dealing with the trade-off among a spectrum of criteria including those related to life-cycle costing and the triple bottom line concept. The results show that the three options for the WSS have the priority values 0.571, 0.632, and 0.631 and the second option is the best fit, while the first is least preferred owing to the high water–energy nexus. The analysis on the sensitivity is conducted revealing that decision-making is susceptible to the criteria weights and some quantification issues when assessing environmental and social sustainability. The third option might be a reversal of decision, against the second, depending partly on the criticality of relevant criteria weights. Finally, the MCSA approach is demonstrated to be employed not only for planning but for detailed design options' comparison later on and for managerial decision-making during operation.