If you're a novice plumber who has just completed their first plumbing project, you probably think your job is done. You've installed all the vents, drains, and water lines, and everything looks great! However, the job isn't finished until you perform a pressure test on your piping to ensure there are no leaks.
Pressure tests for PVC piping systems are generally mandatory to pass a plumbing inspection. They're the only way to ensure your pipes won't leak or burst when full of water. Pressure testing requirements vary by a multitude of factors, such as state, county, and city, so it’s essential you ensure you’re up to code wherever your project is located.
While pressure testing your plumbing system sounds simple, it's a somewhat complicated procedure, especially for newbies. However, regardless of how inconvenient or difficult it is, pressure testing your PVC pipes is essential to have peace of mind and avoid future plumbing problems.
Important Tips and Precautions When Performing a Pressure Test for PVC Pipe
Before going straight to the PVC pipe (see our piping products) pressure test, it's essential to make the necessary preparations. There are also certain precautions you should be aware of depending on the type of pressure test you're using.
• If you're performing a pressure test with water, it's important to have somewhere to drain the water when you're finished.
• Don't let the PVC pipes you’re testing make contact with any solvents, chemicals, or dilutants that could impede the integrity of the test.
• If you're performing an air test, you must use the correct gauge and avoid pumping the pipes too full of air.
• You should also remove the test plugs with extreme caution when you're finished. The high amount of air pressure could result in damage or injury if you remove the plug too quickly.
• If you're performing a water pressure test during winter, you should insulate pipes prone to freezing.
• Don't make any repairs to your plumbing system while the test is ongoing and the pipes are full of air or water.
How to Perform a PVC Pipe Pressure Test
Once you've taken the proper precautions, you're ready to perform your pressure test. Because water pressure tests are becoming the norm, let's look at how to perform a PVC pipe pressure test using water.
Cap Off the Main Drain Exiting the House
The first thing you'll need to do is cap or plug the main drain where it's exiting the house. At this point, the city will not yet have connected to the main drain, and it should be exposed. You have two options for plugging this drain.
1. Use a plumbing plug that inserts into the end of the drain. Turn the knob on top of the plug to widen the flange on the inside and make an airtight seal.
2. You can also use an inflatable plumbing balloon to plug the pipe. To do this, insert the deflated balloon into the end of the pipe. Next, use a hand or electric pump to inflate the balloon inside the pipe to form an airtight seal.
Install Plugs or Caps on Individual Stub Outs
When the main drain is plugged, go back inside the house and plug each of the drain stub-outs. You should have drains stubbed out in the kitchen, laundry room, bathrooms, and anywhere else you have a plumbing drain. You can use the same method as you did with the main drain to plug each stub out, or you can glue a PVC cap on the ends of the drains.
Plug or Cap Your Toilet Drains
At this point of the plumbing process, your toilet drains should be flush with the floor. Therefore, you can use the methods listed above or install toilet flanges with caps on them.
Fill the Drain System with Water
Once all the stub outs and drains are sealed, you can fill your plumbing system with water. To do this, use a garden hose attached to a nearby spigot. You can use the washing machine drain in the laundry room or a vent as the point of entry for the water. These are typically the highest points in your plumbing system and will allow all your pipes to fill with water.
It's essential to fill the system slowly so that any air inside the pipes has time to escape through the plumbing vents. For this reason, don't plug vents protruding through the roof until they're full of water.
Fix Problems as Needed
If you notice any leaks while performing the test, drain the system and fix the leak before proceeding.
Ensure the Water Level Hasn't Changed
Depending on your building inspector and inspection code, the plumbing system will need to hold water for anywhere from an hour to a day. At the end of the allotted time, check the highest point of your plumbing system, typically where you added water, and ensure the level hasn't gone down. If it has held steady, you're good to go!
What About When You're Pressure Testing with Air?
Most of the steps above will be the same if you're performing a PVC air pressure test. The only difference is that you'll pump the system full of air rather than filling it with water. And, rather than checking the water level at the end of the test period, you'll use an air gauge and ensure that the pressure hasn't decreased.
What is the Purpose of a Pressure Test?
There are two fundamental reasons to perform a pressure test on plumbing systems that use PVC pipe. First, your plumbing system will need to pass a plumbing inspection before construction can proceed, and a pressure test will be part of the inspection.
Second, pressure testing is the only way to ensure your plumbing system won't leak when it's full of water. Otherwise, you'll be left guessing until you get called out to fix your mistake when a furious homeowner calls to inform you about a water leak.
Does all PVC Need to be Pressure Tested?
Because it is crucial to have a safe, reliable, leak-free plumbing system, all PVC pipes included in the drain, sewer, or venting systems should get pressure tested. Pressure testing is the only way to guarantee that your plumbing system will hold and not leak when it's full of water.