The City of Madison has a population of approximately 213,000 and is the capital of the state of Wisconsin. The City of Madison is served by a municipally owned and operated water utility under the direction of the Madison Water Commission. As part of Madison Water Utility's bonding requirements, an update to the Madison Water Utility's Water System Master Plan and Capital Improvement Plan is required every five years. The Utility has been complying with this requirement since 1963. In 1998, the Utility decided to prepare a new Master Plan rather than simply updating the previous Plan. The key element of the new Master Plan was the creation of an accurate, full pipe model of the existing water system. This paper discusses the selection of hydraulic modeling software and the successful use of an existing geographic information system and digital information with this software. Includes figure.