Water and Wastewater Terms Beginning A

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

air gap

An open, vertical drop or vertical empty space between a drinking (potable) water supply and the nonpotable point of use. This gap prevents the contamination of drinking water by backsiphonage because it stops wastewater from reaching the drinking water supply. Air gap devices are also used to provide adequate space above the top of a manhole and the end of the hose from the fire hydrant.