An air gap eductor comprising: an upper assembly including: (i) a receptacle for receiving a water supply, (ii) a water jet nozzle, a lower assembly including: (iii) a discharge tube having an upper end, a lower end, and an inside surface surrounding a passageway through the discharge tube, the upper end of the discharge tube having a transverse opening comprising an unobstructed water jet receiving portion and a rim portion, the rim portion being between the water jet receiving portion and the inside surface of the discharge tube, the water jet receiving portion being aligned to receive a jet of water from the water jet nozzle of the upper assembly; (iv) a venturi structure inside the discharge tube, the venturi structure being between the upper end of the discharge tube and the lower end of the discharge tube, (v) a liquid entrainment side passageway into the venturi structure, and (vi) a backflow deflector (48, 102) between an air gap and an inlet into the venturi structure; and a connecting structure connecting the upper assembly to the lower assembly, the connecting structure providing an air gap between the water jet nozzle of the upper assembly and the backflow deflector of the lower assembly; characterized in that the backflow deflector (48, 102) comprises a transverse backflow deflector plate, the deflector plate blocking a first part of the rim portion of the opening at the upper end of the discharge tube while leaving unblocked both the water jet receiving portion of the opening as well as a second rim part of the opening at the upper end of the discharge tube, the blocked first part of the rim being from 40 to 80 percent of the rim area and the unblocked second part of the rim being from 20 to 60 percent of the rim area, with the blocked first part of the rim and the unblocked second part of the rim providing a bifurcated asymmetry from 40% to 100%. an upper assembly including: (i) a receptacle for receiving a water supply, (ii) a water jet nozzle, (i) a receptacle for receiving a water supply, (ii) a water jet nozzle, a lower assembly including: (iii) a discharge tube having an upper end, a lower end, and an inside surface surrounding a passageway through the discharge tube, the upper end of the discharge tube having a transverse opening comprising an unobstructed water jet receiving portion and a rim portion, the rim portion being between the water jet receiving portion and the inside surface of the discharge tube, the water jet receiving portion being aligned to receive a jet of water from the water jet nozzle of the upper assembly; (iv) a venturi structure inside the discharge tube, the venturi structure being between the upper end of the discharge tube and the lower end of the discharge tube, (v) a liquid entrainment side passageway into the venturi structure, and (vi) a backflow deflector (48, 102) between an air gap and an inlet into the venturi structure; and (iii) a discharge tube having an upper end, a lower end, and an inside surface surrounding a passageway through the discharge tube, the upper end of the discharge tube having a transverse opening comprising an unobstructed water jet receiving portion and a rim portion, the rim portion being between the water jet receiving portion and the inside surface of the discharge tube, the water jet receiving portion being aligned to receive a jet of water from the water jet nozzle of the upper assembly; (iv) a venturi structure inside the discharge tube, the venturi structure being between the upper end of the discharge tube and the lower end of the discharge tube, (v) a liquid entrainment side passageway into the venturi structure, and (vi) a backflow deflector (48, 102) between an air gap and an inlet into the venturi structure; and a connecting structure connecting the upper assembly to the lower assembly, the connecting structure providing an air gap between the water jet nozzle of the upper assembly and the backflow deflector of the lower assembly;