Spotting and locating a pool leak

A pool in the Var typically loses 2 to 5 mm a day in high summer through evaporation. Without a heatwave or strong wind, more than 3 mm becomes suspicious. More than 1 cm a day, and it's certain: there's a leak.

The only truly reliable test is the bucket test.

1. Fill a bucket with pool water and set it on the first step, three-quarters submerged. 2. Mark the level in the bucket and the level in the pool with a marker pen. 3. Turn off filtration and don't swim for 24 hours. 4. Compare 24 hours later.

If both levels drop the same amount: it's evaporation. If the pool drops more than the bucket: it's a leak.

In order of likelihood in the Var:

• Skimmer or return-jet seals: the number one cause, often invisible.
• Pump or fittings in the plant room: look for damp patches on the floor.
• Fixtures: light fitting, vacuum point.
• Liner: rare, but visible at a fold or on the floor.
• Buried pipework: the rarest and hardest to locate.

Filtration off for 24 hours, level still drops: the leak is on the pool shell or the suction pipework.

Filtration running for 24 hours, level drops faster: the leak is on the return pipework or the plant room.

That's the first sorting step a pool professional does. You can do it yourself.

If after these tests you know there's a leak but can't locate it, that's the time to call. A pool professional uses pressure testing and acoustic detection to pinpoint it to the centimetre.

Leak detection is quoted individually, starting from €349 depending on the methods needed. An untreated leak can lose several cubic metres a week — and the bill climbs fast with the Var's water prices.