Rough In means to bring Plumbing pipes to the space, but not make the final connections. For plumbing, this would be the pipes in the walls and floors that lead to the sinks, bath, toilets, etc., but not actually hooking up those fixtures. When we installing plumbing rough in don’t be concerned with how rough it looks. It only needs to function properly and hold the required pressures, it doesn’t need to look pretty. That’s what finish work for. Around the same time, our plumbers comes in and runs supply and drain pipes through studs and under floors to kitchen and bathroom sinks, showers, bathtubs, laundry rooms, etc. Inspectors make the first visit and approve or fail the work. FUNCTIONAL MEANS EVERYTHING BY CODE.