The three stages of plumbing are typically referred to as rough-in, trim-out, and final inspection. Rough-in: During this stage, the plumbing system is installed, including the pipes, fixtures, and valves. This stage also includes installing and connecting the main sewer line and ensuring that all pipes are properly secured and supported. Trim-out: During this stage, the visible fixtures and appliances, such as toilets, sinks, faucets, and showerheads, are installed and connected to the rough-in plumbing. This stage also involves installing and connecting any necessary electrical or ventilation systems. Final inspection: Once the trim-out stage is complete, a final inspection is performed to verify that all plumbing components are installed correctly and to code. This stage also includes pressure testing and flushing the system to ensure that everything is functioning properly. These stages are typically performed by licensed plumbers, who are trained and experienced in installing and maintaining plumbing systems. Proper plumbing installation is essential for ensuring the health and safety of building occupants and the environment, as well as maintaining the functionality of the plumbing system over time.