Design and operation of hydraulic systems can be an extremely complex task. Although not widely accepted the application of deterministic optimization techniques can provide guidance to decision makers. However, when uncertainty is considered or as reliability limitations are imposed, optimization models become much more difficult to solve. Procedures to handle these difficult problems have been developed with some success. The Task Committee on Integration of Reliability, Uncertainty, and Optimization in Hydraulic Systems is reviewing these past efforts, summarizing the state of the art in stochastic optimization and identifying future research needs. This paper provides an overview and categorization of problem types.