If you place this unit next to the accessible lavatory or other required clear space and don't allow room for the projection, it may interfere with the minimum required clear floor space, door maneuvering clearance, or turning space. Having the additional volume helps to minimize housekeeping trips for overflowing waste receptacles, but the designer must keep the 4" projection in mind when laying out the toilet room. I've asked Bobrick to revise their description to "semi-recessed", but to-date, there's been no response. Good unit. Just use common sense when laying out the toilet room.