Abstract: Air gap assembly for preventing backflow from a waste line to a dishwasher or other appliance connected to the line. The assembly comprises a vertically extending hollow body, an inlet tube extending upwardly within the body, an outlet tube connected to the body, an air vent in the body in proximity to the upper portion of the inlet tube, and a deflector cap mounted on the body above the inlet tube. Water entering the device through the inlet tube is deflected in a downward direction toward the outlet tube without leakage through the air vents, and the air vents prevent syphoning action which might otherwise produce undesired backflow from the waste line to the appliance connected to the inlet tube.