Why Is My Pool Losing Water? (Evaporation vs. Leak)Updated a month ago
A dropping water level can be stressful—is it just evaporation, or do you have a leak? In our climate, both are possible. Here’s how to diagnose the issue and fix it, whether you’re battling summer heat or seasonal storms.
Is It Evaporation?
Normal evaporation causes water loss of 2–5cm per week, depending on:
Hot, dry weather (common in summer).
Wind exposure (increases evaporation).
Humidity levels (low humidity = faster evaporation).
Quick Test: The Bucket Method
Fill a bucket with pool water and place it on the pool steps (submerged halfway).
Mark the water level inside the bucket and on the pool wall.
Check after 24 hours.
Same loss: Evaporation.
Pool loses more: Likely a leak.
Note: If you have an automatic pool water leveler don't forget to turn it off when checking for leaks!
Signs of a Leak
Water loss exceeds 5cm weekly (without extreme heat).
Soggy patches, sinkholes, or erosion around the pool.
Algae growth despite proper chemical levels (leaks dilute chlorine).
Air bubbles in the pump or inconsistent skimmer suction.
Cracks in the pool shell or loose tiles.
How to Find & Fix a Leak
1. Check Common Leak Locations
Skimmer or return fittings: Cracks in plastic or loose seals.
Pool lights: Faulty conduit seals.
Pump or filter: Damp spots, hissing sounds, or pressure loss.
Underground plumbing: Wet soil near pipes or valves.
2. Use a Leak Detection Kit
Dye test: Squirt leak detection dye near suspected cracks or fittings—if it’s drawn out, you’ve found the leak.
Pressure test: For plumbing lines (best left to pros if unsure).
Explore our Leak Detection Kits for DIY tools.
3. Temporary Fixes (Until Repairs)
Vinyl pools: Use underwater epoxy or patch kits.
Concrete/fibreglass: Apply hydraulic cement or silicone sealant (for small cracks). (Underwater Pool Repair Kit / Corkit)
Plumbing leaks: Turn off the affected line and call a professional.
For minor leaks up to 3mm in width, try using a leak sealing chemical (Marlig Fix A Leak Sealer)
Solutions for Evaporation
Use a pool cover: Reduces evaporation by 70–90%. (Daisy Pool Covers)
Install windbreaks: Hedges or fencing to minimise wind exposure.
Top up wisely: Use a rainwater tank to refill and avoid chemical imbalance.
When to Call a Pro
Suspected structural leaks (cracks in the shell or floor).
Underground pipe leaks (requires specialised equipment).
Persistent leaks you can’t locate after DIY testing.
Prevent Future Water Loss
Inspect seals and fittings annually.
Maintain proper water chemistry: Corrosion from imbalanced pH can damage pipes.
Winterise pipes if closing the pool in cooler regions.
Final Tip: Don’t ignore water loss—evaporation is manageable, but leaks only get worse (and costlier!). Test early, patch small issues, and invest in a cover to save water and money.