Abstract: A sprinkler or water circulating system having a selected number of sprinkler heads, bubblers or the like, each having an associated valve mechanism adapted to effect valve closure upon displacement of the sprinkler head, bubbler, etc., during water flow thereby preventing loss of sprinkler effect and fluid. A normally open spring loaded valve is positioned in a conduit to which the sprinkler head or the like is attached. A stem or rod is positioned in engagement between sprinkler head and valve so that upon displacement the stem may be broken off if of frangible material, or otherwise displaced and the valve is urged into closed position. Upon replacement of the sprinkler head or the like in proper position the rod is replaced to maintain the valve in open position.