Question

what is the recommended distance for an air gap? three times the diameter of the water faucet 2 inches or less at least half an inch twice the diameter of the water supply inlet

Explanation:

In plumbing and water - supply systems, the recommended air - gap distance is three times the diameter of the water faucet to prevent back - siphonage and ensure water safety.

Answer:

Three times the diameter of the water faucet