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Terms & Synonyms

Official WHO Definition

Water from the kitchen, bath and/or laundry, which generally does not contain significant concentrations of excreta (WHO 2006).Untreated household used water-- such as wash or rinse water from a sink, bathtub, or other household plumbing fixture, except a toilet (Symons et al. 2000). Water that consists of non-toilet waste water (World Plumbing Council Working Group 2008).See also Graywater. 

Other Definitions


Interpretations and Explanations

Greywater may be reused with appropriate treatment which is often less than required for black water. Greywater reuse where fresh drinking water is scarce is a valued water resource. The use of greywater to reduce the demand on drinking water use will increase as fresh water resources are exhausted. Greywater should be treated before use as greywater which is not treated will carry increased health and environmental risks (World Plumbing Council Working Group 2008).  Greywater has limitations of use to protect public health and to reduce environmental risks. Greywater can be safely used for flushing toilets (can save a minimum of 20% of household water), garden irrigation, washing cars or external hose down applications, filling ornamental pond, firefighting, and construction purposes (Plumbing Industry Commission and Water Authorities 2005).


WHO (2006) Guidelines for the safe use of wastewater, excreta and greywaterPlumbing Industry Commission and Water Authorities (2005) Recycled Water Plumbing Guide. Victoria Australia. Symons, J.M., Bradley, L.C. Jr. and Cleveland, T.C. (2000) The Drinking Water Dictionary. American Water Works Association

WHO Lexicon page (translations and examples)

See also

External Resources


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