Water Legacy, the only U.S., IAPMO approved greywater reuse system will help you earn LEED points in your residential construction.  LEED’s Water efficiency credit will gain one point for a 20% reduction in water usage and a one more point for a 30% reduction, for a total of two points. The New construction rating system v2.2 specifically states.  ” Potential Technologies and Strategies- Use high-efficiency fixtures, dry fixtures such as composting and waterless urinals, and occupant sensors to reduce potable water demand.  Consider reuse of storm water and greywater for non potable applications such as toilet flushing and urinal flushing”