Abstract: A pop-up sprinkler having a sprinkler head which is arranged in response to pressure water flowing therethrough to automatically elevate to a position above the ground for watering purposes and to lower itself to a position below the ground surface when the water pressure is removed, the sprinkler head being supported on a vertical movable riser tube slidably located within a tubular housing, the arrangement being such that during the ascent and descent of the riser tube, water flows across the outer surface of the riser tube and the inner surface of the stem to thereby flush same. Descent of the riser tube is aided by means of a spring having hooks at its upper and lower ends, with the upper hook attached to a legged spring clip abutting a shoulder on the riser tube, and the lower hook attached to a retention pin traversing the housing stem.