How to Pressure Test Pool Lines

Written by Michael Dean
April 3, 2024

swimming pool plumbing diagram

Your pool’s plumbing system should remain clear and free of any leakages for optimal functioning of your pool. But it can be tricky to sniff out a leak. Pressure testing is one way to establish if there’s a leak and where it might be.

Pressure testing is a reliable way to identify if there are leaks within the pipes, and there are two methods to do it: air and water. In this article, I will go over how to pressure test your pool lines. Let’s get into it!

Main Takeaways

  • You have two options when pressure testing your pool lines: An air test or a water test.
  • Be careful when testing your pool lines. Always wear proper protective gear, do not exceed the recommended pressure, increase pressure gradually, and follow other safety tips.
  • If you have a small leak, you should be able to DIY the fix by using epoxy putty, but if you have a larger or more complicated leak, hire a professional.

How to Pressure Test Pool Lines

If you suspect you may have a leak in your pool plumbing system, you’ll want to perform a pressure test. There are two different ways to pressure test pool lines: 1) an air test or 2) a water test. I’ll go over both methods below.

Step-by-Step Process: Air Test

An air test is the fastest and easiest way to find leaks in your swimming pool lines. It is the method I use most often. However, this method can be challenging to identify smaller leaks and to read exact measurements. 

Supplies Checklist

  • Air compressor
  • Skimmer, return line, and drain plugs/caps

Step One: Isolate the Line

Shut off the pool pump and filter. Block off all other lines except the one you’re testing using plugs or caps on the skimmer, return lines, and main drain.

Step Two: Attach the Pressure Tester

Locate an access point on the isolated line (this is usually near the equipment pad). Screw in a pressure testing plug or adapter specifically designed for pool lines. Connect your air pressure tester (double-check that the safety valve is functional) to the adapter.

Step Three: Pressurize the Line

Slowly fill the line with air using the compressor. Target a pressure of around 15 to 20 psi (or whatever is the recommended level for your pool’s plumbing system).

Step Four: Detect the Leak

Listen for a hissing sound and look for air bubbles around the exposed pipes, fittings, and pool structure.

Step Five: Monitor the Drop in Pressure

If you can’t find any immediate leaks, monitor the pressure gauge for a drop over time. Make sure the pressure remains stable. A significant drop (more than 1 psi) within a few minutes suggests a leak. A small initial drop might be air filling the gauge and may stabilize.

Step-by-Step Process: Water Test

The water test is another way to test your pool lines. It is arguably more accurate at detecting leaks and cancels out the need for an air compressor (a standard garden hose should suffice!). This method is a surefire way to find even the smallest leaks. However, it does mean a slower setup since it takes time to fill the line with water. Leaks also might be a bit harder to pinpoint.

Supplies Checklist

  • Garden hose
  • Plugs and caps for lines, skimmer, and drains
  • Teflon tape

Step One: Isolate the Line

Just as with the air test, you’ll need to shut off the pool pump and filter when performing a water test on your lines. Block off all other lines except the one you’re testing using plugs or caps on the skimmer, return lines, main drain, etc.

Step Two: Attach the Garden Hose

Connect the garden hose to a pressure testing rig—make sure it’s sealed tightly (use Teflon tape if needed). Once this is done, turn on the water supply.

Step Three: Pressurize the Line

Monitor the pressure gauge, open the valve, and fill the line with water. Aim for 15-20 psi or whatever is recommended for your pool. Once it reaches this level, close the valve and isolate the pressurized water.

Step Four: Detect Possible Leaks

Inspect the entire pool system, including all the fittings and pipes. Look for anything that might be dripping or leaking or for any spurts of water. 

Step Five: Monitor the Pressure Drop

Like with the air test, monitor the pressure gauge for a drop over a period of time. If the pressure remains steady for around 60 seconds, you’re all good to go! However, if the pressure slowly drops more than 1 psi, then check for any leaks.

If you can’t find any leaks in the isolated line, check your pressure test setup to ensure it is not leaking and retest before you wholly determine that there is a leak in your pool line.

Step Six: Release the Pressure

Once the test is over, release pressure slowly by opening the valve on the adapter or the pressure tester.

If you’re unsure about performing the test yourself, you could also consider hiring a pool professional to help you and walk you through the process for any potential future leaks.

Safety Tips for Pressure Testing Pool Lines

Here are some safety tips to keep in mind when pressure testing the pool lines.

Do Not Exceed the Recommended Pressure

Pool lines are mainly designed for a maximum pressure of 15 to 20 psi, but always check the recommended numbers for your specific pool’s plumbing. Do not exceed this limit. Doing so could cause the pipe to burst, which can be extremely costly.

Increase Pressure Gradually

When testing, always increase the pressure slowly, in gradual increments. This prevents sudden spikes that might lead to ruptures in the system.

Use the Right Plugs and Adapters

It is important to use pressure-testing plugs and adapters specifically designed for pool lines. A faulty or incompatible plug might detach under pressure.

Wear Protective Gear

Even a pressure of 10 to 20 psi can shoot a pressure testing plug like a missile toward you or into the air, so always wear protective gear! Make sure to don a pair of safety glasses to shield your eyes from any spurts of water or possible debris blowouts during the test. On top of safety glasses, wear a face shield, some kind of hearing protection, and heavy clothing.

Stay Clear

Stay clear of capped lines or fittings while the system is pressurized in case of a leak or blowout—you don’t want to be whacked in the face by a sudden burst of debris.

You should also ensure your family stays away from the pool at this time!

Inspect Before Testing

Before pressurizing the pool lines, thoroughly inspect any existing cracks, weak spots, or loose fittings. If you spot any troubling concerns, address them before proceeding with the test.

Grab a Partner

Two heads are better than one. If someone is around, have them assist you during the test. A second set of eyes to monitor the pressure gauge and identify possible issues is always useful.

Check with an Expert

If, at any point, you’re unsure how to test or release pressure or any other part of the process, please check with a pool expert about possible doubts you might have. It’s always safer to minimize risks by following professional advice.

What to Do with a Leaking Pipe

So, with the help of a pressure test, you’ve identified a leak in your pool lines. What do you do now?

Step One: Try to Contain the Leak

Act quickly to contain your leak, if possible. Locate the shut-off valve for the leaking pipe (this is usually near the water meter) and turn it off.

Step Two: Turn off Electricity

In case the leakage is located near electrical outlets or appliances, shut off all appliances to prevent potential electrical hazards.

Step Three: Assess and Identify

Once you’ve identified the source of the leak, assess the severity of the situation. Can you repair it yourself, or does it require professional assistance? 

Step Four: Use Epoxy Putty (for Minor Leaks)

If the leak is minor, you should be able to fix this leak yourself by applying moldable epoxy putty to the area.

Step Five: Call a Plumber or Pool Expert (for Complex Repairs)

In case of larger leaks, a burst pipe, or tricky locations, I strongly encourage you to call a licensed plumber or pool professional to properly repair the affected area. Doing so can help prevent the issue from worsening even further. While some minor issues can be easy to DIY, major repairs are best left to experienced plumbers.

Remember, it’s best to act quickly once you spot a leak. Even a small leak can quickly become a major plumbing disaster down the line!

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Frequently Asked Questions

What PSI Should Pool Lines Be?

Pool lines don’t have a specific psi themselves. They’re equipped to handle the typical operating pressures of a pool’s plumbing system, which usually hovers around 5 to 20 psi. But always check what pressure your own pool lines should be, as they differ from pool to pool.

What Pressure Do You Test Pool Water Lines At?

During pressure testing, you may need to raise the pressure to around 15 to 20 psi or whatever is considered normal for your pool’s plumbing.

Maintain a Leak-Free Swimming Pool

Pressure testing pool lines helps identify pesky leaks within your pool’s plumbing system. With two different types of pressure tests to choose from and by following basic safety protocols, any pool owner can ensure a successful and non-hazardous testing process.

Do you have further doubts or need to discuss how to approach pressure testing your pipes further? Drop me a message!

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