How to check plumbing pressure

When installing plumbing in a new construction or during a remodeling, local building codes may require an inspector to perform a pressure control. To avoid having to pay high fees or fail inspection, you can check the pressure of your pipe prior to the visit of the inspector. Even if your pipe is not to be checked, you can check the pressure to verify the quality of your facility, and identify and solve any problems before it is serious.


  1. Prepare the system. It is preferable that you check the supply of water and drainage system (drainage, waste and vent) when all the pipes are installed, but before they are covered or inaccessible. The pipes must be dry and the main valve closed.
  2. Blocks the drainage system. For a pressure measurement, you will need a system without air leaks. It locks the ventilation pipes and empties the T-joints close to the main pipe. Seal all openings, such as drains and water intakes. You can do this using sticky plugs or inflatable connection plugs.
  3. Connect the pressure pump and the meter. Following the manufacturer’s instructions, connect the pressure pump and meter to an appropriate part of your drain system, such as a washer.
  4. Pressure the plumbing system. Operate the air pump until the meter registers five pounds (2.27 kg) per square inch (PSI).
  5. Monitor the pressure. Check pressure gauge constantly for at least 15 minutes. If the pressure is kept constant at five psi, your drainage system is safe and has passed the test. However if the test fails surely you must have a loss somewhere.
  6. Check for leaks. Even if the pressure stays constant during the test, you can inspect your drainage system for signs of small leaks, such as a soft hiss or an air leak. If the pressure fails during the test, or if you suspect for any other reason that there is a leak, you can also check the joints by applying a small amount of soap with water and watching for air bubbles.
  7. Repair the losses. Once you have identified the source of a leak, you can solve the problem by reinstalling or replacing the loose, defective or damaged parts of the pipes. Then you can perform the pressure test again to verify that the problem has occurred or find out what repair should be performed.
  8. Test the water supply lines. Generally, you can perform a pressure test on the supply lines simply by opening the water outlet and controlling the entire extension of the system to detect any leakage that the water pressure reveals. However, if you prefer an air pressure test, you can follow the same steps as with the drainage system.

Tips & Warnings

  • You can buy the necessary equipment and tools in a hardware store or plumbing store, you can also rent the equipment for less cost in a rental business.
  • Check local building codes, or call a licensed inspector to find out if a pressure test is needed, and find out about any specific requirements, such as pressure and time testing.
  • When performing an air pressure test, wear safety goggles and other protective equipment. Be extremely careful, especially when checking seals and seals. High pressure could cause the joints to come off at high speed, or create other potential hazards.