In this article
Once you know your pool is losing more than normal evaporation, the real question is where the water is going. Knowing whether the source is in the floor or the walls changes the whole repair approach, including whether draining is needed. The good news is that a pool gives plenty of clues if you know how to read them. This guide walks through those clues and shows how to combine them into a clear picture for you and your technician.
Confirm the leak first
Before searching for a location, make sure a leak exists. In hot, dry weather evaporation can look like a leak. The simplest check is the bucket test, explained in our article on evaporation versus leaking. If the pool clearly drops more than the bucket, you have a real leak. Record everything, including the daily drop, pump status and weather. Those notes underpin every conclusion that follows.
Level behaviour is the first clue
- The water stops at a certain line, which usually means the leak is at that height, such as a horizontal crack, a light niche or the skimmer. That points to the walls.
- The water keeps dropping with no clear stopping line, making the floor, the main drain or its pipe more likely.
- Fast loss when full that slows as it drops can suggest an upper wall leak, as water pressure on the point falls.
This is not conclusive alone, but it narrows the search considerably. Never let the level fall below the skimmer with the pump running.
Signs of a floor leak
- Continuous dropping with no stop line.
- Visible cracks in floor tiles or deposits gathering in one spot.
- Floor tiles slightly raised or sunken.
- Sand or soil appearing near the main drain.
- Settling paths or cracked paving nearby, as escaping water affects soil under and around the pool.
- Damp in a basement or room below floor level.
Signs of a wall leak
- The level stops at a fixed line.
- Clear horizontal or vertical cracks in tiles or render, especially near the waterline.
- A band of hollow-sounding tiles.
- Damp or efflorescence on the outside of one wall or the ground beside it.
- Worn grout around lights, returns or the skimmer.
- Dark stains that return in the same place after cleaning.
Using a dye test to confirm a spot
- Turn off the pump and wait for the water to be completely still.
- Approach the suspect point slowly without stirring the water.
- Release a tiny amount of pool test dye next to the crack or fitting.
- If the dye is drawn into the point and disappears, the leak is confirmed.
- Repeat around other fittings such as lights and returns.
Dye testing is easy on walls near the surface but harder on a deep floor, where it needs diving and very clear water, so floor detection is usually a specialist job.
Floor and walls side by side
| Indicator | Floor | Walls |
|---|---|---|
| Level behaviour | Keeps dropping | Stops at a fixed line |
| Where damage shows | Pool floor and surrounding soil | A wall band or one side |
| Ease of inspection | Harder, may need diving or lowering | Usually easier from the surface |
| Typical repair | May need partial or full drain | Usually lowering to the area only |
| Long-term risk | Soil and foundation effects | Local tile and waterproofing damage |
A pool can have more than one source at once. A visible wall crack does not rule out a floor or pipe leak, so always run a follow-up test after the first repair.
When you need a specialist inspection
- Signs point to the floor or buried pipes.
- Paths or surrounding floors are settling or cracking.
- The loss is large and growing.
- A previous repair attempt failed.
- You need a written report before a larger renovation.
At YAM Pools inspection starts with a free site visit, followed by pressure tests on pipe lines and targeted checks of walls, floor and fittings. We then provide a report and written quotation, with a written warranty on workmanship and waterproofing, across Riyadh and all Saudi cities. Learn more about our leak detection service.
- Confirm the leak with a bucket test.
- Watch where the water stops.
- Look for damp and settling around the pool.
- Try dye near points close to the surface.
- Call a specialist if signs point to the floor.
Frequently asked questions
Can a pool leak from both floor and walls?
Yes, especially older pools. That is why the pool should be tested after each repair to confirm the loss has fully stopped.
Does a floor leak always mean draining?
Not always. Some cases are handled by diving or underwater repair products, but major damage or weak floor waterproofing may require a partial or full drain.
Do hairline wall cracks cause leaks?
Some are only in render or grout, while others reach the waterproofing and concrete. Dye tests and a specialist check show whether a crack actually passes water.
Can I try the dye test myself?
Yes, carefully, around points near the surface, with the pump off and pool test dye. Leave the deep floor to a technician.
