Verified Simulation Models (VSMs) of sewers and watermains are playing an increasingly important role in any planned upgrading of these pipeline systems. Such models are crucial to optimizing system performance and cost effectiveness in major infrastructure upgrading programs. The significance of why such models must confidently replicate existing system performance is briefly explained before acknowledging that VSMs of existing pipeline systems are considerably more expensive than traditional modeling approaches. In analyzing the cost of VSMs it is recognized that a significant proportion relates to model building and there is a need to reduce such costs to a minimum. Therefore methods that link to GIS or use GIS technology have been investigated and developed and these are outlined.