This powerpoint presentation begins by providing a problem statement that includes: the City of Ottawa required an update to the Water Distribution System Master Plan in order to meet level of service expectations over the planning period (2031) with a cost-effective system expansion plan. Study objectives were to: find a least cost system expansion plan that will meet future demands at adequate pressure, meet reliability criteria, and avoid water quality issues; define system operations strategy; develop infrastructure phasing plan; and, develop decision support tool for future updates. The approach involved: using Genetic Algorithm (GA) technology and a hydraulic model to test a wide range of system expansion alternatives; converging on an optimal solution through an iterative process involving "GA runs" and "offline" reliability and water age improvements; and, results of reliability and water age improvements impose further constraints on the GA by reducing number of available capacity alternatives. Topics covered include: introduction to Genetic Algorithms; description of optimization model; City of Ottawa Water Distribution System; development of alternatives; and, results.