A line stop adapter includes a body having a tapping flange mounting surface, adapted for mounting to a tapping sleeve flange, and an opposing valve mounting surface, adapted for mounting to a temporary valve. An interior wall forms a body aperture fluidly connecting the mounting surfaces. A portion of the interior wall is adapted to receive and selectively engage a completion plug, allowing the completion plug to fluidly seal the body aperture. Multiple engagement portions are arranged around the body aperture for securing the tapping flange mounting surface to the tapping sleeve.