What do we call the parts of a plumbing system installed before fixtures?

Rough-in refers to the phase of plumbing installation where the essential infrastructure, such as pipes and drains, is installed before the final fixtures—like sinks, toilets, and faucets—are put in place. This stage is crucial for ensuring that the plumbing system is properly laid out and meets building codes, which include regulations on water flow, drainage, and venting. It sets the foundation for the plumbing work and is often conducted before walls are built or finished surfaces are completed.

The rough-in stage typically includes the installation of water supply pipes, waste lines, and vent pipes, which must be tested for leaks and compliance with code requirements before moving on to finish plumbing, which is the installation of visible fixtures and fittings. Understanding the rough-in phase is important for contractors and builders, as it affects the overall layout and function of the plumbing system.