Pool losing water? Leak detection in Mallorca

Your pool level keeps dropping and you are not sure why. Before assuming the worst, remember that Mallorca in summer is an evaporation machine: hot days, warm water, sea breeze and long sunshine hours can legitimately remove 5 to 10 mm of water per day. The real question is whether your pool loses more than that, and answering it takes one bucket and 24 hours.

This guide walks you through the bucket test, the usual leak locations, the tests professionals use, and what a leak actually costs you in water while it goes unfixed. It is part of our overview of pool repair in Mallorca.

Key takeaways

• Evaporation in a Mallorcan summer is typically 5 to 10 mm per day; losses beyond that suggest a leak.
• The 24 hour bucket test reliably separates evaporation from a real leak with no tools beyond a bucket and tape.
• Most leaks sit in fittings and accessories: skimmers, light niches, return jets and overflow channels, not in the shell itself.
• Refilling a standard 8 x 4 metre pool of about 48 m3 costs roughly 100 to 150 EUR, so an ignored leak quietly burns money every month.

Step one: the bucket test

Fill a bucket with pool water and stand it on a step so the rim sits above the waterline and the bucket water matches pool temperature. Mark the water level inside the bucket and the pool level outside it with tape. Run the pump on its normal schedule and wait 24 hours. If the pool level dropped clearly more than the bucket level, water is leaving through something other than evaporation. Repeat once with the pump off: if the loss is worse with the pump running, suspect the pressure side pipework; if it is worse with the pump off, suspect the suction side or the shell.

Where pools leak: the usual suspects

Skimmers, lights and return fittings

The joint between the plastic skimmer body and the concrete shell is the single most common leak point, because the two materials expand differently. Light niches are next: the cable conduit behind the lamp can siphon water out steadily. Return jets and their glued connections follow. A simple observation helps: if the level always stabilises at a certain height, the leak usually sits at that height. Level stops at the bottom of the skimmer mouth, think skimmer; stops at the light, think light niche.

Overflow channels and balance tanks

Infinity and overflow pools add a whole second circuit: the perimeter channel, its drain lines and the balance tank. Cracked channel joints and tired tank waterproofing are frequent causes of mystery losses in these systems, and because the tank is out of sight the leak can run for months. If your overflow pool loses water or the channel no longer drains properly and floods the surround, have the channel and tank inspected as a system rather than chasing the main shell.

Underground pipes

Buried suction and return lines fail at glued joints, at elbows and where ground movement stresses the pipe. These are the leaks owners cannot fix themselves, but they are also the ones professionals find quickly with the right kit.

How professionals find leaks

The standard toolkit is pressure testing and dye testing. In a pressure test each pipe run is plugged and pressurised; a line that cannot hold pressure has a leak, and listening equipment or tracer gas locates the spot without blind digging. Dye testing works inside the pool: with the pump off and the water still, a syringe of dye released near a suspect fitting gets pulled visibly into any opening. Electronic listening devices, moisture meters and cameras complete the picture. A competent company combines these and gives you a written diagnosis before any repair quote; the price of the repair then depends on where the leak is and how much access work it needs, which is why serious firms quote after testing, not before.

What a leak costs you in water

A leak of just 3 mm per day on a 32 m2 pool is roughly 0.1 m3 daily, around 3 m3 a month, and leaks are rarely that polite. Refilling a full 48 m3 pool costs about 100 to 150 EUR in most Mallorcan municipalities, and constant topping up also throws away the chemicals and heat in the water. Water is a scarce resource on the island, and agencies such as the EPA WaterSense programme document how much household water losses add up. Finding a leak usually pays for itself within a season.

DIY checks vs professional detection

Everything up to and including the dye test is safe owner territory. Pressure testing, opening light niches and any digging belong to professionals, both for warranty and safety reasons. Our free service connects you with vetted leak detection specialists across the island; see the pool repair service page for what is covered. If detection reveals damage that ends in a bigger project, our renovation cost guide shows what full works cost in Mallorca.

Conclusion

Measure first, then act: the bucket test tells you in a day whether you have a leak, and professional detection finds it without wrecking the garden. Every week of delay costs water, chemicals and possibly ground stability. Request free quotes from leak detection specialists here, choosing Pool Repair as the project type.