A center pivot irrigator water purging assembly incorporating an overhead pipe supporting a multiplicity of sprinkler drop tubes and a purge pipe; and further incorporating an adaptor pipe communicating with the purge pipe; an “E” bracket fixedly attached to the adaptor pipe; a diaphragm actuator fixedly attached to the “E” bracket; a disc and valve stem attached to the diaphragm actuator for movements between first and second positions, the disc seating against the adaptor pipe in the first position and displacing from the first position in the second position; and a diaphragm actuating shunt having an input end attached in communication with the lower end of one of the irrigator's sprinkler drop tubes.