Service
Inground Vinyl Liner Leak Detection
Above-ground and vinyl liner describe two different things: one is how a pool is built, the other is what lines the inside of it. Most above-ground pools are vinyl-lined, and plenty of inground pools are too. Above-ground pools have their own detection page; this one is about inground pools with a vinyl liner. In a liner pool the vinyl is what holds the water in, so any failure in it leaks directly, and the damage is often invisible unless someone looks for it carefully. We test inground vinyl liner pools throughout our coastal North Carolina service areas.
How we check a liner
A liner leak is found by working along the places the vinyl is joined to something else rather than searching the surface at random: the welded seams, the bead track that holds the liner at the top of the wall, and every fitting that passes through it. We dye test at each suspected point, and the dye is either drawn in or it is not.
Fittings need particular attention. Wherever a return, skimmer, light or step bolt passes through the vinyl, a hole was cut at installation and sealed against a gasket. These fail far more often than the liner material itself.
On an inground liner pool the plumbing is buried, and that changes the order of the work. A leak in a line under the deck looks identical from the surface to a leak in the vinyl, so the lines are isolated and tested — pressure tested where that applies — before anyone inspects a liner inch by inch. Blaming the liner for a buried line is an expensive mistake.
The pool stays full throughout. Dye needs water above a leak to be drawn into it, and an inground pool should not be drained in any case: the weight of the water is what holds the shell in the ground, and an empty liner can shrink and may not fit properly again.
Where a liner leak can be repaired, we repair it. We do not replace full liners, and we will tell you plainly if a liner is past the point where a repair will hold.
Where vinyl liners leak
- Seams
- The welds holding the liner panels together. A seam that has started to separate leaks along its length, so it is traced rather than marked at a single point.
- Bead track
- The track that holds the liner at the top of the wall. If the liner pulls away here, the water is lost down to the level of the separation and then holds.
- Fittings
- Returns, skimmers, lights and steps: every one is a hole cut in the liner at installation and sealed against a gasket.
- Punctures and tears
- Usually small, often in the floor, and easy to walk past without dye to confirm them.
- Behind the liner
- On an inground liner pool the buried plumbing can be losing the water while the vinyl is intact. Testing each line separately is what rules that in or out.
Tell us about your pool
Describe what you are seeing, and we will tell you what it may mean and what a visit would involve. If the water level is dropping fast, call us. You will reach a family-owned, owner-led team.
Is my pool a vinyl liner pool?
If the inside of the pool is a fitted sheet rather than plaster, gunite, tile or fiberglass, it is a liner pool. The easiest place to check is the top of the wall, where the liner is held in a track under the coping or the top rail. Inground and above-ground pools are both built this way; this page covers inground liner pools, and above-ground pools have their own page.
Can a liner leak be invisible from the deck?
Often, yes. A puncture in the floor, a seam that has only begun to open and a bead track separation are all hard to see, and none of them leaves a mark you would notice from outside the pool. That is what dye testing is for.
Could the plumbing be leaking rather than the liner?
It could, and that should be ruled out before anyone quotes you for liner work. On an inground liner pool the lines are buried, and a leak in one looks the same from the surface as a leak in the vinyl. We test the lines separately.
Do you have to drain the pool to find a liner leak?
No, and on an inground pool draining it would be the wrong thing to do. The weight of the water holds the pool in the ground, an empty liner can shrink, and with no water above the leak there is nothing to draw dye into it.
How is a liner pool different to test from a gunite pool?
In a gunite pool the shell itself holds the water, so the search covers cracks in the structure. In a liner pool the vinyl holds the water, and its weak points are where it is joined to something else: the seams, the bead track and every fitting cut through it. The plumbing is tested the same way in both.