How to Complete a Plumbing Pressure Test

If you have made the decision to install new plumbing during a renovation or new home construction project, the local building codes may require you to hire a building inspector to complete a pressure test. Those looking to avoid any unnecessary fees or a failed inspection may decide it is a good idea to test the system on their own in advance. Even if the inspector will not be testing your system, you can utilize a test to help you figure out the exact quality of the installation, while also identifying any issues you may not have noticed otherwise before they become a more serious problem. In this article, we will outline the basics of a DIY plumbing pressure test.

Step 1 – Preparation is key. Ideally, you’ll want to test drainage, waste, vent, and water supply pipes during the installation process. This will allow you access to all of the pipes without having to get through any pesky drywall or brick. Make sure that the water supply is off and the pipes are dry.

Step 2 – Block your drainage, waste, and vent pipes. In order to properly test the plumbing you will be required to begin the process with a system that is airtight. Block your drain and vent pipes at the T-fittings next to the main stack. Be sure to plug any openings, including fixture and drain stub-outs. This can be accomplished with the aid of solvent-glued plastic caps or test balloons.

Step 3 – Connect the pressure gauge and air pump. Make certain to follow all of the instructions provided by the manufacturer. Connect the pressure gauge and air pump to the DWV line and an access point that proves convenient.

Step 4 – Next, you will need to pressurize the system. This is done by running the pump until the gauge registers at a point of 5 lbs per inch.

Step 5 – Once you’ve hit your mark, pay close attention and monitor the pressure, keeping an eye on the gauge for at least 15 minutes. If you notice that the pressure remains constant for that period of time, your lines are good to go and have passed the test. If your pressure happens to fall, you are likely looking at a leak.

Step 6 – Keep an eye out for leaks. Even when pressure is constant, you may find yourself in a situation that requires you to trace the path of the DWV pipes in order to check for leaks. If you notice a drop in pressure during your test or if a leak is suspected, you can check your fittings by way of applying a small amount of soapy water to the suspect area and looking for bubbles.

Step 7 – If you happen to find a leak, you can fix the issue by resetting the fittings. Once the fittings are properly reset, you will be able to conduct a new test in order to help you confirm whether the issue has been solved or if work is still required.