PURPOSE: To simplify the structure and assembly of and improve the reliability of a plumbing fixture check stop by moving a valve member away from the inlet of a sleeve as determined by the position of an adjustment member by the action of water pressure acting on the valve member.

CONSTITUTION: A check stop 102 for use at the inlet of a plumbing fixture such as a flush valve holds a sleeve 186 between a pipe 184 and a flange 188, and a valve member 190 placed in butt contact with a valve seat 192 defined on the sleeve 186. The valve member 190 is pressed on the valve seat 192 by a spring 202 seated on a flange 206 as determined by the position of an adjustment member 198 the stroke of which is limited by a stud 200. When the flush valve is operated, the difference in internal water pressure between the pipe 184 and a conduit 180 causes the valve member 190 to move away from the valve seat 192 or slide in the sleeve 186 for compression of the spring 202 until its valve stem 194 butts against the adjustment member 198 into a stop. This expedient simplifies the structure and assembly of the check stop 102 and also improves its operational reliability.