Finding a pool leak before the bill arrives

A pool leak is rarely dramatic and almost always expensive. Not because of the water – because of what the water does underground when it escapes unnoticed for months.

The awkward part: in a Mallorcan summer the level drops visibly anyway. At first, evaporation and a leak look identical.

The bucket test: evaporation or leak?

The test costs nothing and takes a day.

• Place a bucket on the top step of the pool so that it stands securely.
• Fill it with pool water until the level inside matches the level outside.
• Mark both levels on the bucket – inside and outside, with tape for example.
• Leave the filter pump on its normal schedule, do not use the pool for 24 hours and do not top up.
• After 24 hours, compare the two marks.

If the pool has dropped noticeably more than the bucket, it is losing water. If both dropped by the same amount, it was evaporation. Rain or strong wind invalidate the test – repeat it on a calmer day.

Where the level stops tells you where to look

When a pool loses water, the fall usually stops at some point. That height is the single most useful observation you can pass on.

If the level settles at the skimmers, suspect the skimmer or its pipework. If it stops at the return jets, suspect those. If it halts at the edge of the light niche, the cable conduit is a frequent cause. If it drops well below every fitting, that points instead to the shell itself or to the floor pipework.

Note the observation – date, time, height. It saves a great deal of searching later.

A second test: pump on or pump off

Some leaks only show under pressure, others only when the system is idle. You can tell them apart.

If the pool loses most while the pump runs, suspect the pressure side – the lines back to the pool and their joints. If it loses most while the pump is off, that points to the suction side or to the shell.

Run the system continuously for a day, leave it off for a day, and compare. It is not a precise measurement, but it narrows the search considerably.

Signs that are easy to miss

• An area of garden that stays noticeably greener or softer than its surroundings.
• Damp patches or efflorescence on the plant room wall, particularly low down.
• Air in the system: bubbles at the return jets, a pump strainer that never fills completely, a motor running unevenly.
• Settlement or new cracks in the surround, in joints or in the paving.
• Water consumption rising for no apparent reason – with a meter or cistern, the earliest visible sign.
• Markedly higher chemical use, because untreated fresh water keeps entering the pool.

When professional detection is worthwhile

As long as the loss is small and the point is likely to be a skimmer or a threaded joint, much can be resolved without special equipment.

Beyond that there are methods that avoid excavation: pressure testing individual pipe runs, acoustic detection, dye testing at suspect points in still water, and in some cases thermography. The cost is modest – set against a dug-up pool surround, essentially always.

Timing is the real lever. A leak found in spring is a repair. The same leak running unnoticed through the winter can affect the substrate, the planting and, in the worst case, relations with the neighbours.

Why a leak costs so much in an empty house

In an occupied house a falling water level is noticed sooner or later. In a property used only part of the year, a leak may run for months.

That is why we regard running water consumption as the single most informative figure in looking after a property. Comparing consumption per day against what is normal for that house reveals a deviation in days rather than in quarters – whether it comes from the pool, from a pipe or from a running cistern.