i didn't catch what rr meant, but it's not a hob overflow. they are built into the back wall of the tank. there are 2 "bump in" on the back wall, inside the tank. there is one socket 'y' at the top of each overflow area, just below the slots. i have a hose bibb coming of the left wall, also the room has it's own breaker box on that side as well. you can also know that the electronic devices are set to that side too, so putting the sump there might cause a problem with crowding, but it could work. i'm not opposed to the fuge & sump, but with space running out and the fuge having to be another big purchase, i'd have to "ponder the ways". i also have a 50 plastic container to put in there somewhere, for the auto top off, unless i bypass that, and come directly from the ri/do.