Rough-in plumbing - includes supply and waste lines

This description involves the initial phase of plumbing installation, known as rough-in plumbing, which includes laying out both the supply and waste lines within a building. Rough-in plumbing is performed before walls and floors are finished and includes installing the pipes that will carry water to fixtures and the pipes that will carry waste away. This foundational work ensures that the plumbing system is properly integrated into the structure, allowing for smooth operation once fixtures are installed.