Considerable research has been done on the optimiztion of water distribution systems. Early research in this area used traditional optimization techniques such as linear and non-linear programming. More recently, genetic algorithms (GAs) have been applied successfully to real-world network planning and design problems. Since 1994, a number of practical applications of GA optimization have been reported in the literature. The focus of these papers has been on the use of the GA optimization technique to identify optimized capital improvement alternatives as part of a system expansion study. The reported results have been very promising with projected capital cost savings of up to 50% when compared to traditional design procedures. This paper describes another important application of GA optimization distinct from the identification of optimized capital improvement plans that involves the investigation of opertional set points and operating procedures to achieve the best overall solution for a distribution system problem. Improvements to system operations may be based on objectives such as reducing operating and energy costs, improving the level of service, lowering risks, providing for maintenance scheduling, or optimizing the utilization of existing assets. Three case studies are presented to illustrate how the GA can be formulated to optimize different operational decisions with the objective of minimizing the lifetime cost of the project.