Plumbing Rough In

A topic to discuss plumbing rough ins, what happens, the process, things to look out for or consider, council plumbing inspections, pressure testing, different reticulation system types (materials), best practices and manufacturers guidelines.


Welcome to the forum! If you’re new to the world of home construction, understanding the plumbing rough-in process is important. This stage sets the groundwork for your home’s plumbing system, ensuring water can flow efficiently to and from your residence into the sanitary system (sewer). Let’s look into what plumbing rough-in entails, the steps involved, and what you should keep in mind.

What is Plumbing Rough-In?

Plumbing rough-in refers to the phase in construction where all the water supply and waste lines are installed. This is done before the walls and floors are finished, making it easier to run pipes and connect fixtures. It includes laying the groundwork for sinks, toilets, showers, and other water-dependent appliances.

The Process

  1. Planning and Layout: Before any work begins, a detailed plan is created. This plan outlines where pipes, fixtures, and appliances will be located. Accuracy in this setout stage (distances, clearances, heights, depths) is important to avoid issues later.
  2. Installing Water Supply Lines: Pipes for cold and hot water are installed. These lines connect to the main water supply and run to various fixtures.
  3. Drain-Waste-Vent (DWV) System: This system ensures waste and water can exit the house efficiently. It includes pipes that connect to the sewer or septic system. This is also caled the vent pipe and is often concealed within a wall frame, extending up and through the roof space and roof materials before a roof cowl (dektite) and vent cap are fitted to seal and weatherproof.
  4. Pressure Testing: Once the pipes are installed, they are tested for leaks. This involves filling the system with water or air to check for any pressure drops that indicate a leak.
  5. Council Inspections: Local councils often require inspections to ensure the plumbing meets all regulations and codes. This step is essential for compliance and safety. The council checks that the system can hold the required pressure and that the pressure limiting valve has been installed to the main water feed.

Things to Look Out For

  • Proper Slope/fall for Drains: Ensuring drains have the correct slope/fall is vital for preventing blockages. Shit does not run up hill, water doesn’t like to but certainly can through capillary action.
  • Correct Pipe Sizes: Using the right pipe sizes for different applications ensures adequate water flow and pressure.
  • Quality Materials: Investing in high-quality pipes and fittings can prevent future leaks and damage.

Council Plumbing Inspections

In Australia, council inspections are mandatory to ensure the plumbing system complies with local codes. Inspectors will check:

  • The placement and installation of pipes.
  • Proper sealing and connection of joints.
  • Compliance with the approved plan.

Pressure Testing

Pressure testing involves filling the plumbing system with water or air and monitoring the pressure. If the pressure holds steady, the system is leak-free. If it drops, there’s a leak that needs to be fixed.

Different Reticulation System Types (Materials)

  • Copper: Durable and long-lasting, but more expensive.
  • PEX (Cross-linked Polyethylene): Flexible, easy to install, and resistant to scale and chlorine.
  • PVC (Polyvinyl Chloride): Commonly used for waste lines due to its low cost and durability.

Best Practices and Manufacturers’ Guidelines

  • Follow Manufacturer Instructions: Always adhere to the guidelines provided by the manufacturers of plumbing materials.
  • Regular Inspections: Periodically check for any signs of leaks or wear.
  • Professional Installation: Whenever possible, hire licensed plumbers to ensure the work is done correctly.

If you have any questions or need further guidance, feel free to ask in this forum!