Residential Water Reuse Fact Sheet

Residential water reuse is a topic of increasing interest. With growing water shortages in the Southwestern United States and other areas, the ability to reuse water onsite as opposed to sending it all to a wastewater treatment facility becomes more and more appealing. Additionally, reuse of water is generally considered to be a part of sustainable resource management practice, so it is increasingly being utilized or considered in areas that do not necessarily suffer from water shortages. Considerations with water reuse include the source of the water to be reused (gray water vs. black water), the configuration of the plumbing system within the facility, the type and quality of treatment of the reused water, and the ultimate purpose of the reuse. In general, reuse focuses on irrigation and other non-potable applications, as opposed to treating wastewater to the point of being considered potable. The treatment requirements are lower for applications where there is little risk of human exposure, such as subsurface irrigation. As exposure risk increases so does the level of treatment required, with the most stringent requirements in place for indoor reuse applications such as toilet flushing.