This disclosure relates to apparatus for cleaning swimming pools, incorporating intermittent pop-up jet nozzles, the nozzles being adapted to intermittently rotate and project cleaning jets of water adjacent the inner surface of the pools. Wear and tear on the nozzle housing and related parts is minimized by use of a water delivery assembly in which the stop means for arresting upward movement of the nozzle are located in the lower part of the housing, thus eliminating bending moment of stress force against the housing and related parts. The inclusion of a retainer or cage within the housing provides other improvements in the operation of the water delivery assembly.