Saving Liquid Gold: Graywater Collection Systems

Graywater systems reduce freshwater demand and CAN save building owners money.

Recently in Colorado, Governor Hickenlooper signed a graywater bill making it legal for homeowners and business to reuse graywater.  Graywater is untreated household wastewater that has not come into contact with sewage.  For example, used water from bathtubs, showers, bathroom wash basins, clothes washers and laundry sinks.  This bill is smart planning – Colorado is expected to have a shortage of more than 3 million acre-feet of Colorado River water by 2060.  The water savings potential of graywater systems is enormous.  Researcher Larry Roesner from the Urban Water Center estimated, “We can save about 50 percent of the indoor demand by using gray water for toilet flushing, and we can save about 30 percent of overall annual demand by gray-water reuse,” Roesner said. “A household of four could save 58,000 gallons a year using gray water, and a 40-home subdivision would save over 2 million gallons a year.”


USGBC’s LEED-NC rating system promotes the use of graywater technology by offering 5 Water Efficiency credits, for a total of 5 points, where the use of graywater is critical strategy for achieving water reduction.  Building owners in Colorado can now confidently install these systems without fear of legal complications.  This has significant cost-savings potential, as prices for water in the arid states is surging.  In Colorado, Developers are paying an 81% cost increase for an acre-foot over just two years ago.  Graywater systems make sense.

If you’re building a LEED building, SBS as a LEED consultant, can assist your team in the selection of Water Efficiency and other credits.  Each project is different, and we specialize in helping you plan, implement, and document the credits selected for the project.

Post your thoughts