In this article
When a pool leaks, the first question is always: where from? The floor, the walls or the pipes? The right answer does not come from guessing but from a sequence of tests, each narrowing the search further. This article explains the technical steps in order, and how the technician finally determines whether the problem is in the floor, the walls or somewhere else entirely.
Step one: confirm and measure the leak
Before searching for a location, confirm there is a leak at all. Pools lose water through evaporation, especially on hot, windy days. The simplest tool is the bucket test: a bucket filled with pool water sits on a step so its water level matches the pool's. Both levels are marked and compared after a day or more. If the pool drops noticeably more than the bucket, the difference is usually a leak. Water loss is then measured over several days with conditions recorded, giving a reference to judge the repair later.
Step two: pump on versus pump off
This simple test splits the problem in two. Water loss is measured with the pump running, then with it off for a similar period:
- More loss with the pump on: likely in return lines, which are pressurised during operation.
- More loss with the pump off: likely in suction lines or the shell.
- Similar loss in both: most likely the shell itself, meaning floor, walls or fittings.
Another useful test is letting the level drop without refilling and watching where it stops. If it stops at a certain level, the leak is usually near it, such as a skimmer, a light or a wall crack. If it keeps falling, the floor or main drains are likely.
Step three: visual inspection and dye testing
The technician checks walls, floor, steps and the areas around fittings, lights and skimmers for cracks, hollow tiles or worn grout, plus the outside: damp soil, sunken decks or stains in the pump room. Then comes the dye test: a small amount of safe coloured dye is released near a suspect point in still water with the pump off. If it is drawn towards the crack or fitting, water is leaving there.
Step four: line pressure testing
If earlier tests point to the pipes, each line is isolated, plugged at both ends and pressurised with water or air while a gauge is watched. A sound line holds pressure; a leaking one loses it gradually. This identifies exactly which line is at fault: main drain suction, skimmer or a return. It does not pinpoint the spot, but it narrows the search and prevents random breaking of sound areas.
Step five: acoustic listening to pinpoint the spot
Once the line is known, sensitive listening equipment picks up the sound of water or air escaping underground or inside concrete. The technician follows the line's route and marks where the sound is clearest, allowing a small, targeted opening instead of long excavation. Accuracy depends on experience, surface type, pipe depth and background noise, so it is sometimes repeated at a quieter time of day.
Step six: underwater inspection and filming
For deep areas hard to see from above, such as the floor, main drains and lower walls, the technician dives or uses a waterproof camera. Footage documents cracks, fittings and grout, and lets the homeowner see the problem without draining.
The verdict: floor or walls?
| Indicator | Usually points to |
|---|---|
| Level stops at a certain height | Walls or a fitting at that level |
| Level keeps falling | Floor or main drains |
| Loss rises with pump on | Return lines |
| Dye drawn in at a light or fitting | Failed waterproofing around it |
| A line loses pressure | Plumbing, not the shell |
Everything comes together in a report stating the source, the proposed repair and whether draining is needed. Tests sometimes reveal more than one source, which is common in older pools. For more, see how to tell a floor leak from a wall leak. YAM Pools follows these steps in order and gives you a clear report, a repair plan and a written quotation, in Riyadh and across Saudi Arabia.
Frequently asked questions
Does engineering leak detection require a full drain?
Usually not. Most tests, including bucket, dye, line pressure and acoustic listening, are done with the pool full. Draining is for the repair if needed.
How long does full leak detection take?
It depends on how many steps the case needs. Measuring loss and watching the level takes more than a day, while pressure testing and listening are often done in one visit.
Is the detection result always final?
It locates the source accurately in most cases, but sometimes an additional source appears after draining or tile removal, especially in older pools.
Can I do the bucket test myself?
Yes, and it is a useful start. Put the bucket on a step, mark both levels and compare after a day or more without refilling or swimming.
