An air gap fitting and method for fluid flow coupling an appliance waste water discharge outlet to a sewer stand pipe inlet. A bell-shaped hood has a side wall skirt tapering downwardly divergently to a skirt lower edge outlet dimensioned to telescopically receive the open upper inlet end of a sewer stand pipe until it abuts a 360.degree. internal slip-stop skirt shoulder. A single hood air vent exterior opening extends axially of the skirt approximately two inches. An interior central drain tube extends downwardly and terminates flush with the hood air vent opening lower edge. A tube air vent gap slot is oriented 180.degree. out of alignment with the hood exterior air vent. A hexagonal protrusion on the hood upper end receives a wrench to rotate or hold the fitting, and accommodates forming a 1/2'' or 3/4'' I.D. female threaded hood inlet.