This paper presents an integrated, computer-based generic framework to couple urban water related models into a decision support tool (DST) for urban-water management. The DST, built on a participatory modelling approach, enables stakeholders to analyze impacts of climate variation, population growth, and alternative management solutions ranging from centralized to distributed options. The coupling of external models, building of the DST, and execution of simulation processes is achieved by employing GoldSim, which is linked to a database management tool and a shared library. A post-processing package generates outcomes for decision makers in the form of a new criterion, the Water System Performance Index (WSPI). The application of DST is demonstrated for the water service area of the Salt Lake City Department of Public Utilities (SLCDPU). Results show that a decentralized alternative increases the reliability of the system without changing the system's vulnerability. Centralized alternative improves the overall performance of the system based on WSPI results, but decrease in performance is still noticeable under the hot and dry climate condition. Overall, the system is very sensitive to changes in climatic conditions. Results show that during droughts, supply management is not the sole solution and compulsory demand-management practices should be instigated.