Is your pool actually leaking, or just evaporating?
If you're topping up your pool more than usual and worrying it might be leaking, the first thing to do is rule out evaporation. The bucket test is how Leakbusters Lanzarote does it for every customer before we charge anyone for a proper leak survey. It takes 48 hours and a plastic bucket, and it's free.
How much water Lanzarote pools lose to evaporation (normal)
Pool evaporation in Lanzarote is genuinely high. We're in the Saharan air mass, the trade winds blow constantly, and the sun is on the water 300+ days a year. Here's roughly what to expect from a typical 8 × 4 metre pool:
- July-August: 6-8 mm a day, around 200-250 litres
- May-June and September-October: 4-6 mm a day
- November-March: 2-4 mm a day
- Windy days: add 20-30% to whichever season you're in
Any of this is normal. None of it is a leak.
What makes it worse for some pools:
- Open to the wind from every side (no walls or buildings sheltering it)
- Big surface area — infinity edges, water features, beach entries
- Heated pool (warm water evaporates faster)
- Light-coloured decking reflecting heat back in
The bucket test
This is how you find out for sure.
You need: a sturdy plastic bucket (15-20 litres), some waterproof tape or a permanent marker, and 48 hours of not swimming.
- Fill the bucket about two-thirds with pool water.
- Sit it on the first or second step of the pool so it's part-submerged but stable.
- Mark the water level inside the bucket.
- Mark the pool water level on the outside of the bucket at the same height.
- Turn off any auto-fill and the pool pump.
- Wait 48 hours. No swimming, no topping up.
- Measure how far each level has dropped.
Reading the result
- Bucket and pool dropped the same amount → it's evaporation. Your pool is fine. Use a cover, you'll cut losses 95%.
- Pool dropped 10 mm more than the bucket over 48 hours → you've got a leak. Call us.
- Pool dropped 20 mm or more than the bucket → you've got a real leak, and worth getting on it before the bill compounds.
Other signs your pool is leaking
The bucket test is the cleanest answer, but these usually go with a real leak:
Around the deck:
- Pavers or tiles shifting
- Cracks in the coping where it didn't crack before
- One area of garden suddenly greener than the rest
- A persistently boggy patch on the downhill side of the pool
The pool itself:
- Tile lifting around fittings, lights, or skimmers
- Grout dropping out or white efflorescence appearing
- Bubbles or soft spots on a fibreglass shell
- Wrinkles in a liner
At the equipment pad:
- Pump running constantly to maintain pressure
- Air coming out of the return jets
- Visible drips around filter, pump, or valves
Where pool leaks usually are
After years of Lanzarote pool work, Leakbusters Lanzarote sees the same leak locations over and over:
- Skimmer throat — where the skimmer box meets the pool shell, thermal expansion cracks it
- Return fittings — repeated tightening of directional eyeballs cracks the surrounding material
- Light niche seals — UV destroys the gaskets eventually
- Main drain joints — ground settlement pulls them apart
- Buried PVC plumbing — joints separate after years of ground movement or were poorly bonded in the first place
- Check valves on the pad — when these fail, water siphons back through the system
Why a leak gets expensive fast
A pool leaking 200 litres a day on top of evaporation costs you €30-60 a month in water alone. The chemicals you keep adding go down the drain with it. The pump works harder maintaining pressure, costs you electricity, and wears out faster. And the wet ground around the pool slowly undermines the deck. Small cracks turn into big cracks. The repair cost goes up the longer you leave it.
How Leakbusters Lanzarote finds pool leaks
Once you've confirmed it's a leak and not evaporation, here's what we use:
- Pressure testing on each plumbing line in isolation — tells us which line has failed without digging
- Acoustic equipment to listen for the leak underground or behind the shell
- Dye testing to confirm shell and fitting leaks visually
- Thermal imaging to see temperature differences where water is moving below the surface
The point of detection is to pinpoint the leak so the repair is targeted, not exploratory. No digging up the whole patio.
Summary
- Evaporation is normal in Lanzarote. 6-8 mm a day in summer is fine.
- The bucket test takes 48 hours and tells you if it's a leak or not.
- If it's a leak, get on it — the cost compounds.
- Call Leakbusters Lanzarote when you've confirmed the leak. No find, no fee.