A wall hydrant assembly for movably positioning a wall hydrant between a first and second structural member includes a first and second rail adapted to be secured to the first and second structural member. The first rail is adapted to engage a first portion of the wall hydrant and the second rail is adapted to engage a second portion of the wall hydrant to allow the wall hydrant to move substantially along the length of the first and second rails. The wall hydrant assembly can include first and second tabs which co-act with the first and second rails. The first and second rails can each define an elongated slot. The first and second tabs can each include a shaft which co-acts with the elongated slot to allow the wall hydrant to be moveable along the first and second rails.