A flush plug and a collar are used in installing a drain or cleanout. A flush plug is temporarily attached to the nipple of a cleanout or to a drain base and leveled. Concrete is then poured flush with the top of the flush plug. After the flush plug is removed from the cured concrete, a collar is installed in the hole in the concrete left by the flush plug. The outside of the lower portion of the collar is beveled like the flush plug. The upper portion of the collar includes a sleeve rising above the top surface of the surrounding concrete by an amount equal to the thickness of the specific floor finish. Tile or other finish may then be laid to around the collar. The installed drain will be flush and level with the flooring around it.