Abstract: The present invention is a drain system for use with a manifold plumbing control unit (MPCU) including a drain pan having a sloping bottom surface with a peripheral wall forming a reservoir. The peripheral wall may include upwardly extending sidewalls, and upwardly extending endwalls secured to the edges of the sloped bottom surface. One or more attachment brackets may extend from the wall to facilitate attachment to one or more wall studs under the MPCU. The drain pan has a unique drain hole assembly in the bottom surface for attachment of a drainage line, that prevents the line from protruding upward to prevent blockage of the drain. A separate access opening is provided in the bottom surface to allow for passage of a water supply line to the MPCU. In alternative embodiments, splash shields may be provided to surround the MPCU to help contain and drain off any spraying or leaking liquid into the drain pan. Methods of installation are also provided.