Pool Losing Water: Leak Detection on Mallorca and the Costs

The water level drops, you top it up, and three days later a few more centimeters are missing. Pool losing water, Mallorca, peak summer: the first question is whether there is actually a leak at all. Where it sits comes second. An open pool loses a surprising amount to evaporation in July, and anyone who calls a company at the first sign of a drop ends up paying for a search that finds nothing. On the other hand, topping up a real leak for months costs you twice over: once through the water utility, and again later repairing ground that has been undermined. Here is how to tell the two apart, where pools on the island typically develop leaks, and what professional leak detection costs. For what else a pool costs over the year, see our guide to running costs on Mallorca.

Evaporation or a leak: the bucket test

Before you call anyone, you need a number: how much is missing per day, and does that match evaporation? In July and August, daytime highs inland regularly top 35 degrees, and there is almost always wind. Under those conditions, an open pool can lose up to a centimeter of water level per day to evaporation alone, five to seven centimeters over a week. Daily swimmers also splash extra water over the edge.

The bucket test separates evaporation from a leak without any tools:

1. Place a bucket on the second step of the pool so it does not float, but its rim clearly sticks out above the water. Weigh it down with a stone.
2. Fill the bucket with pool water up to the level of the pool's own water line.
3. Mark both levels with tape: inside the bucket, and outside the bucket at the height of the pool water.
4. Turn the pump off for 24 hours. Nobody swims, nobody tops up.
5. Compare the next day: if both levels dropped by the same amount, it was evaporation. If the pool dropped noticeably more than the bucket, you have a leak.

Repeat the test with the pump running. If the pool only loses water then, the problem is in the pressure line or the filter. If it only loses water with the pump off, the suction side or the pool shell is affected. Equal loss in both cases points to the shell or a fitting.

Where pools on Mallorca typically develop leaks

Many fincas have concrete pool shells from the eighties or nineties, often finished with gresite mosaic tile, sometimes with a liner added later. On top of that, ground tends to settle during dry summers. When a pool like this loses water, it is usually one of four spots.

The skimmer is the classic culprit. It sits at the junction between the pool wall and the plastic housing, exactly where the material has to cope with 40 degrees in August and frost on a clear January night. A hairline crack opens up in the seal, and water seeps behind the wall. The second common spot is the underwater light fittings and their cable seals. The gasket ages, and the cable conduit carries water straight from the pool into the ground, with nothing visible on the surface.

The most expensive case is underground pipework. Between the pool and the plant room there are often 10 to 20 meters of PVC pipe buried in the ground, sometimes under the terrace. If the ground settles or a pine root presses against it, a joint can break. That usually only becomes visible once terrace tiles start to sink or a damp patch appears. Finally, there are grout lines and cracks in the concrete: a hairline crack loses little on its own, but a hundred open joints in the gresite tile add up. You can find how to spot cracks yourself and what repairs cost in our post on pool repair on Mallorca.

A dye test gives you a first clue: with the pump off, use a pipette to add food coloring close to the suspected spot. If the color trail gets pulled into a joint, that is where the leak is. This works well on skimmers, jets and lights, but not on underground pipes.

How professional leak detection works

Leak detection on a pool is the systematic search for the leaking spot without draining the pool or breaking up the terrace. Specialist companies pressure-test the pipework line by line, apply dye at fittings, and listen for the leak using electro-acoustic equipment or ultrasound. The goal is a marked spot rather than an opened-up terrace.

Budget two to four hours for the appointment, and turn the pump off the day before so the technician starts with a settled water level. Older fincas rarely have a plan of the pipework, so the technician has to trace the lines with the detection equipment first.

What leak detection costs on Mallorca

For detection alone, without repair, Spanish specialist firms on the mainland quote 150 to 400 EUR, depending on the method and effort involved. On Mallorca, travel costs come on top, since most companies are based around Palma. If you live far out, make sure that is itemized separately in the quote. For repairs, the following rough figures apply, though they vary a lot depending on access:

The ranges are wide because access drives the price. A pipe under gravel is exposed in an hour; the same pipe under a bonded natural-stone terrace takes a full day plus a stonemason. Get every quote in writing, with detection, repair and surface reinstatement itemized separately.

When repairing is no longer worth it

A single leak at a skimmer, jet or light fitting is worth repairing. It looks different if detection turns up several spots and the pool is older than 25 years. At that point the grout in the gresite tile has often become brittle across large areas, and every sealed spot is followed by a new one the next summer. As a rule of thumb: if you hit a third round of detection and a third repair within two years, weigh the costs against a new coating or a liner. For an 8 by 4 meter pool, that runs to a mid four-figure sum and deals with grout lines, hairline cracks and porous surfaces all at once. The same applies to old pipework: once the second joint fails, the rest tends to follow, and a new pipe run is cheaper than opening the terrace every couple of years.

Why a leak in 2026 is also a water problem

On Mallorca, a leaking pool in 2026 has a second dimension: the water itself. The island's water reserves stood at around 46 percent in summer 2026, and the Balearic government classifies the island's supply zones by drought index. You can check the current status of your zone on the Balearic government's water portal. In late August 2026, Manacor moved the Manacor-Felanitx zone from pre-alert to alert, warning that use restrictions and temporary cutoffs would be the next step. Esporles already bans filling private pools from the drinking water network across its entire municipal area.

In some municipalities, topping up simply is not allowed anymore, so a leak can no longer just be left alone. You can find which rules apply where and what a water tanker costs in our post on filling a pool under water restrictions. On top of that, municipalities such as Manacor have introduced progressive water tariffs and individual meters. If a leak keeps you permanently above normal consumption, you slide into the expensive tariff band. And the Balearic land-use law already limits new pools on rural land to 35 square meters of surface area and 60 cubic meters of volume, as set out in Article 68 bis of Ley 12/2017 in the BOE. The wind is turning against private pool water use, and a pool losing a cubic meter into the ground every week is starting to get noticed.

For scale: an 8 by 4 meter pool with a depth of 1.5 meters holds around 48 cubic meters. If it loses an extra two centimeters a day to a leak on top of evaporation, that adds up to roughly 19 cubic meters a month, around 40 percent of the pool's total volume. Under progressive tariffs that quickly turns into a mid two-figure sum a month, and the water is missing from the aquifer.

How much water can a pool on Mallorca lose per day?

Up to one centimeter of water level per day is normal in peak summer due to evaporation, and a bit more with wind and heavy use. If the level drops noticeably faster than the water in a bucket placed next to it, you have a leak.

Can you find a pool leak without draining the pool?

Yes. Pressure testing the lines, dye testing and listening with a geophone or ultrasound all work with a full pool. A diver checks and seals underwater spots directly.

Conclusion

Pool losing water on Mallorca: the answer to the most important question costs you a bucket and 24 hours of patience. Evaporation accounts for up to a centimeter a day in summer; anything beyond that is a leak. Professional detection costs 150 to 400 EUR plus travel, is often deducted if you go ahead with the repair, and saves you an opened-up terrace. And because topping up is restricted in more and more municipalities, finding a leak quickly is also the cheapest way to keep your water bill and your ongoing pool costs under control.