Abstract: An irrigation sprinkler or water gun is retracted into an underground pit during non-irrigation periods, while the pit is closed by a heavy cover which is simultaneously lowered onto the pit opening. The sprinkler is mounted on a telescopic lifting unit which is connected to a point of an underground water supply system and is raised by water pressure as soon as this system is pressurized. The sprinkler communicates with the telescopic unit through a pressure relief valve which is opened by the water pressure only after the sprinkler has been raised to its highest point above ground. As soon as this valve opens water is admitted to the sprinkler which starts to rotate and to irrigate the area.