The technology available for the production of high purity water in a microgravity environment is applied to a water reclamation and purification system for the Laboratory Module of Space Station Freedom. The system is required to remove a wide range of contaminants from water, and therefore a staged system, which uses a number of purification techniques in series, is necessary. The Ultrapure Water System (UPWS) design has been in development for over four years. Initial system concepts relied heavily on distillation, followed by ion exchange and adsorption. Recent efforts have focused on addressing the limitations of a distillation-based system. Substituting a combination of chemical oxidation and continuous deionization for the distillation step appears to be viable.A development test program has been formulated which would prove system feasibility, refine the design concept, and provide data for system simulation. The test program proposes a “breadboard” pilot plant which would be comprised of components that are candidates for inclusion in the flight system.Other considerations, such as weight, power consumption, volume occupied, materials of construction, data channels required, methods of bioburden control, safety, and methods of handling generated waste are crucial to the development of the optimum design. These factors are balanced against the technology available which lends itself to the microgravity and resource constraints of Space Station Freedom, and conclusions are drawn relative to the best combination of components to comprise an advanced flight system.