A Home Master Reverse Osmosis with the optional permeate pump will produce about 1:1 gallons purified per gallon wasted. A typical Reverse Osmosis unit uses four gallons of water for every gallon of pure water produced. However, the optional non-electric permeate pump reduces water waste by up to 80%, increases production by up to 50%, and produces slightly cleaner water as it reduces TDS Creep. Also, you can utilize this rejected water for purposes other than drinking water.