What is "Rough In" plumbing?

Just like it sounds, to rough in plumbing is essentially the rough draft to a later more finalized plumbing installation. Like a rough draft, the job is incomplete at this stage, but unlike a rough draft, changes or alterations to the layout are not expected at this stage.  The point is simply to get the basic plumbing skeleton in place. This way, while the rough in plumbing work pends inspection from a professional who will ensure things are up to code and eventually issue a building permit, the other stages of construction or remodeling can move forward without the pipes of a fully finished plumbing system getting in the way and causing obstructions.