A plastic pan and a plastic drain plug assembly is disclosed. The pan has upstanding walls, a bottom wall, an exterior surface and an interior surface. One of the walls has an opening extending through it. On the exterior, the opening has a circular raised collar with cutouts opposite each other and stop tabs located between the cutouts. On the interior, the opening has a circular raised non-threaded tubular wall. A portion of the non-threaded tubular wall has nibs projecting into the opening. The plug has a head portion, a body portion, an end portion. The head portion has an upstanding crown with downwardly extending tabs located opposite each other. The body portion has a circular groove, and a spiral groove. The end portion of the plug is tapered.