Back siphonage


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Terms & Synonyms

Official WHO Definition

Back siphonage is the reverse flow of water within a water supply system due to negative pressures in the pipe system enabling atmospheric pressure to force the flow of water backwards through a siphon action (World Plumbing Council Working Group 2008).  The reversing of normal flow resulting from negative or subatmospheric pressures in the distribution piping of a drinking-water supply system (WHO 2006).

Other Definitions


Interpretations and Explanations

Back siphonage can occur as a result of excess demand such as fighting a fire where unusually large volumes are required and pressure is reduced (World Plumbing Council Working Group 2008).


WHO (2006) Health aspects of plumbingWorld Plumbing Council Working Group (2008) 

WHO Lexicon page (translations and examples)

See also

External Resources


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