Corrected entry: Mr Roper can hear the roommates' bathroom through the sink and the pipes, indicating that they are right on top of each other. However based on how the apartments are set out in the building and the locations of each bathroom in their respective apartments, it would be impossible for him to hear the bathroom so, if at all.
luke f
28th Apr 2017
Correction: If you're familiar with the show, the Ropers' front door and the roommates' front door upstairs are both on same side of the building separated by one flight of stairs. The inside of each apartment we see (as viewers) are from opposite sides. So when we see the Ropers' bathroom all the way right, we also see the roommates' bathroom all the way left. So in theory more or less, they ARE approximately on top of each other.