Terms used in articles on backflow testing. Air Gaps– Physical separation between a potable water system and a receiving vessel or source of contamination. Air gap between the outlet of the potable system and the flood level rim of the receiving vessel or any source of contamination must be at least twice as large as the diameter

In order to explain what backflow testing is, we first must understand what backflow is. Backflow is the flow of water in reverse caused by reduced water pressure or loss of water pressure from the water supplier.  In simpler terms, backflow occurs when water flows away from a building rather than towards a building. Most