Which description correctly identifies an air gap?

• A. A link between safe and unsafe water.
• B. A type of backflow preventer.
• C. A physical separation between safe and unsafe water to prevent backflow.
• D. A device for measuring water pressure.

Answer: (C)

An air gap is a physical separation between the potable water outlet and the inlet of any non‑potable water system, creating an atmospheric break that stops backflow. This air space prevents contaminated water from being drawn back into the clean supply even if pressures change on the non‑potable side. It isn’t a device that controls flow or a backflow preventer, and it isn’t a connection between safe and unsafe water. It also isn’t something used to measure water pressure. So the correct description is a simple, physical separation between safe and unsafe water to prevent backflow.