Design of a water distribution system is a multi-level process from preliminary planning to final detailed sizing of components. Unfortunately as in many design problems, a final detailed solution is sought before the goals and the purpose of the system being designed are understood. As the planning process progresses system performance is established and decisions are made regarding the required level of performance under different conditions. Often this understanding occurs during an engineer's trial and error judgement based process while using simulation model to analyze the system. This paper discusses how optimization can be integrated in a design process and the advantages of this technique versus trial and error.