According to Arizona State Rule, what is the minimum separation distance for an air-gap separation?

The correct choice regarding the minimum separation distance for an air-gap separation is based on standards set to ensure safe water supply and prevent contamination. An air gap is a physical separation between the end of a water supply line and the surface of the receiving vessel. This separation is vital for preventing backflow, which could lead to potential contamination of the potable water supply.

The requirement of an air-gap separation of either 1 inch or twice the diameter of the supply pipe, whichever is greater, establishes a flexible yet comprehensive standard. This rule accommodates various pipe sizes and contexts, ensuring that even larger pipes maintain adequate separation to protect against any potential siphoning or backflow situations.

This measure emphasizes public health safety by ensuring there is always sufficient space to prevent cross-connection with non-potable water sources. Therefore, the standard provided in the correct choice considers both the functional needs and the physical realities of different plumbing scenarios, promoting the integrity of the water distribution system.