Pool Patchers

Pool Pressure Testing: How We Find Plumbing Leaks

Not every leak is in the liner. Pressure testing checks your pool's underground plumbing — the skimmer, return, and main drain lines — so we know whether water is escaping through the pipes or through the vinyl before we do anything else.

Book a Leak DetectionSee All Our Tests

What It Is

A pressure test isolates the pool's plumbing — the skimmer, returns, and main drain lines — and pressurizes it with water. A gauge on the line shows whether that pressure holds steady or drops. A drop means the line is losing water somewhere along its run, which points to a leak in a pipe joint or fitting rather than the vinyl liner itself.

How We Do It

We shut down the pump and plug the plumbing lines at the returns and drains inside the pool, then pressurize the system with water and watch the gauge. If the pressure holds, the plumbing is intact. If it drops, we move to the equipment pad to narrow down where the leak is — splitting the system into its intake and return sides, then down to the manifold if needed — pinpointing the problem line before anyone starts digging. If everything holds pressure, that rules the plumbing out entirely and points us toward the liner instead, where our liner leak detection process and dye testing take over.

Why It Matters

  • Plumbing and liner leaks look identical from the water-loss numbers alone — a pressure test is what tells them apart.
  • Skipping this step risks patching a liner that was never the problem, while the real leak keeps draining the pool.
  • A clean pressure test result gives you a written answer — useful for a plumber referral, an insurance claim, or your own peace of mind.

Pressure Testing FAQ

What is a pool pressure test?
A pressure test checks the pool's plumbing for leaks — both the underground lines (skimmer, returns, and main drain) and the equipment on the pad, in case the real problem is the pump or filter. We plug the lines, pressurize them with water, and watch a gauge for a drop. A steady gauge means that section is holding; a drop points to a leak in a pipe, fitting, or piece of equipment rather than the liner.
How is a pressure test different from dye testing or liner leak detection?
A pressure test checks the plumbing lines running underground and behind the walls, along with the fittings, the pipe threads at the liner, and the equipment housings. Dye testing and liner leak detection check the vinyl liner itself — the visible surface the plumbing connects to. Running a pressure test first tells us which side of that connection the leak is actually on, so we don't spend time inspecting a liner that's perfectly fine. After a pressure test, we'll sometimes dye-test the threads at the returns and drains to confirm a leak there — a common spot after a winter freeze or if a fitting or housing gets bumped.
Do you have to dig up the yard to pressure test the plumbing?
No. The test itself is non-destructive — we connect to the lines at the equipment pad and the pool's fittings, pressurize them with water, and read the gauge. No excavation is needed to run it. If a line does test positive for a leak, locating and accessing that exact section is a separate, more targeted step — and repairing underground piping may mean digging up part of the yard to reach it.
Can you repair a plumbing leak found during a pressure test?
We specialize in vinyl liner repair. If a pressure test shows the leak is in the underground plumbing rather than the liner, we'll tell you plainly and refer you to a licensed plumber — see our partners page. That's still a useful result: it rules out the liner and points you to the right fix.

Not sure if it's the plumbing or the liner?

We'll run a pressure test and tell you exactly which it is — then fix it if it's the liner.

Book a Leak DetectionLeak Detection Service