Okla. Admin. Code § 310:257-9-15
An air gap between the water supply inlet and the flood level rim of the plumbing fixture, equipment, or nonfood equipment shall be at least twice the diameter of the water supply inlet and shall not be less than 25 mm (1 inch).
Added at 23 Ok Reg 2358, eff 6-25-06
Amended at 38 Ok Reg 1947, eff 9-11-21