Standard Article

Gray Water Reuse in Households

Domestic Water Supply

  1. Fayyaz A. Memon,
  2. D. Butler

Published Online: 15 APR 2005

DOI: 10.1002/047147844X.dw29

Water Encyclopedia

Water Encyclopedia

How to Cite

Memon, F. A. and Butler, D. 2005. Gray Water Reuse in Households. Water Encyclopedia. 1:16–19.

Author Information

  1. Imperial College, London, United Kingdom

Publication History

  1. Published Online: 15 APR 2005


Owing to growing population and uneven distribution and consumption of resources, existing water resources in many parts of the world are experiencing stress. Providing of potable water to meet this ever-increasing demand may become even harder to achieve due to anticipated and emerging climatic change. One way of managing water demand is to reuse gray water.

Reusing gray water reduces the need to use potable water for non potable applications, and the water is effectively used twice before discharge to the sewer. The major reuse potential is for toilet flushing and garden watering that bring the benefits of conservation of water resources and relief of demand on both public water supplies and sewage collection and treatment facilities (1).

Gray water is a loosely defined term representing discharges from wash basins, baths, showers, dishwashers, and washing machines. This generally excludes wastewater from kitchen sinks and toilets, commonly known as black water. Gray water accounts for about 50% of total household water consumption.


  • gray water;
  • reuse;
  • recycling;
  • storage;
  • treatment;
  • filtration;
  • disinfection;
  • water demand management