grey water

noun

household waste water that can be reused for some purposes without purification, e.g. bath water, which can be used to water plantsCompare black water
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Examples from the Web for grey water

  • Garth's eyes sought the landing-stage, then swept the vista of grey-water ahead of them.

    The Hermit of Far End|Margaret Pedler