The mission of the Gray Water / Black Water Center of Expertise in Sustainability (GW/BW-CXS) is to provide knowledge creation and sharing throughout USACE in the area of gray water and black water recycling systems. Gray water recycling systems receive discharge from bathtubs, showers, lavatories, clothes washers and laundry sinks. Gray water systems can be located at individual buildings or piped to a central treatment system from a group of buildings. The recycled water can be used for flushing toilets and urinals, and irrigation. The CXS will provide support to Army Corps of Engineers designers through several avenues such as the Sustainment, Restoration and Modernization (SRM) Web site, webinars, updating guide specifications and Unified Facilities Criteria (UFC), and helping establishing Engineering and Construction Bulletins (ECBs). Black water recycling involves the treatment of effluent from waste water treatment plants to a higher level of sanitation and redistributing the water through purple piping systems to be used for flushing toilets and urinals, and irrigation. The Gray Water/Black Water CXS can provide support in the design of the treatment systems and piping distribution systems. The CXS can also assist in life cycle cost analysis (LCCA) to determine the feasibility of these systems.