<P> An air gap, as it relates to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture . </P> <P> A simple example is the space between a wall mounted faucet and the sink rim (this space is the air gap). Water can easily flow from the faucet into the sink, but there is no way that water can flow from the sink into the faucet without modifying the system . This arrangement will prevent any contaminants in the sink from flowing into the potable water system by siphonage and is the least expensive form of backflow prevention . </P>

What is an air gap in a dishwasher
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