Is Your Pool Leaking? Pool Leak Detection Explained

Pool leak detection is the process of finding exactly where your pool is losing water. A leaking pool wastes water, chemicals and money – and on Gauteng’s water tariffs that adds up fast. The good news is most leaks are easy to confirm, and proper pool leak detection pinpoints the source so it can be fixed for good.

Early detection matters. A small leak left alone means more water lost, higher bills and ground that stays wet around the shell. Over time that wet ground can damage the pool and the paving around it. Confirming the leak early keeps the repair smaller.

Signs your pool is leaking

• Water dropping faster than normal evaporation
• Constantly topping up and re-dosing chemicals
• Damp patches, soggy ground or movement around the pool
• Air in the pump or a drop in circulation
• A higher water bill with no other explanation
• Algae that keeps returning, or pH that will not stay stable, because fresh water keeps diluting your chemicals
• Cracks in the surface or loose tiles
• Paving or decking that has sunk or lifted near the pool
• Air bubbles coming out of the return fittings

The bucket test (do this first)

Fill a bucket with pool water, stand it on a step so the inside and outside water levels match, and mark both. After 24 hours, compare. If the pool has dropped more than the bucket, the difference is a leak rather than evaporation.

Evaporation is higher in hot, dry or windy weather, which is why the bucket sits in the pool. Both the bucket and the pool lose water to the same sun and wind, so only the extra loss counts. Leave the pool pump and any automatic top-up system as they normally run for the first test.

Simple checks you can do yourself

• Run the test with the pump on, then off. Repeat the bucket test with the pump switched off. If the pool only loses extra water while the pump runs, the problem is more likely in the plumbing or equipment than in the shell.
• Turn off any automatic refill. Then watch your water level daily against a marker or a strip of tape on the wall.
• Dye test. Stand in calm water, hold still and release a small amount of dye close to a suspected crack, the skimmer, a light or a fitting. If the dye is pulled towards the opening, water is escaping there.
• Inspect the equipment. Look at the pump, filter, valves and pipe connections for drips, wet spots, corrosion or stains.
• Listen at the pump. Gurgling, air in the basket or unusual noise points to air getting into the system.
• Check the skimmer and return fittings. Look for cracks or gaps where the fitting meets the pool wall.

How pool leak detection works

Water can escape through the shell or a crack, the plumbing lines, the skimmer, the lights, or the fittings. Pool leak detection is detective work – we pressure-test and dye-test to find the exact source rather than guess and patch.

Three kinds of pool leak

• Equipment leaks: the pump, filter, valves and their connections. These are usually the easiest to see and fix.
• Structural leaks: cracks or holes in the shell or the surface finish, and gaps around the skimmer and lights.
• Plumbing leaks: the suction and return pipes running underground. These are the hardest to find, because you cannot see them.

The detective work: pressure testing and dye testing

Each test answers a different question, so the source is confirmed rather than assumed.

• Pressure testing isolates the plumbing lines. Each line is tested on its own, so a line that cannot hold pressure shows up as the culprit and the rest are ruled out.
• Dye testing checks the shell, lights, skimmer and fittings. Dye placed at each suspect point shows whether water is drawn out through a crack or a poorly sealed fitting.

Because the source is pinned down first, any digging is limited to the spot that needs it.

When to call a professional

• The pool is losing a lot of water quickly.
• You suspect a leak underground or under the paving.
• Your own checks have not found the source.
• The loss continues after the equipment and fittings are checked.

Fixing the leak

Surface and crack leaks are repaired as part of pool renovation or resurfacing; plumbing leaks are traced and repaired with minimal digging. Either way, the fix should address the cause so it doesn’t return.

Fixing the symptom is not enough. Patching a crack without finding out why it opened, or replacing a section of pipe without testing the rest of the line, invites the same leak back. Once the source is confirmed, the repair is done to deal with that cause. Everything is handled in-house by Trademen Pools’ own experts, from detection through to the repair, so the people who found the leak are the ones who fix it.

Repairs come with a guarantee. Piping carries a 1-year guarantee, remarbelite carries 5 years and refibreglass carries 5 years. Guarantees are honoured for normal wear. They do not cover damage from natural causes such as weather, or from interference such as someone walking on a fresh finish.

When the leak is in the surface, the repair is a remarbelite or a refibreglass, and each normally takes 3 to 5 days.

Frequently asked questions

How do I know if my pool is leaking or just evaporating?

Do the bucket test: float a bucket of pool water on a step and mark both water levels after 24 hours. If the pool drops more than the bucket, you have a leak.

Can a leak be found without digging up the yard?

Yes. Pressure-testing the plumbing and dye-testing the shell, lights and fittings pinpoints the source, so any digging is targeted rather than guesswork.

How much does pool leak detection and repair cost?

The cost depends on where the leak is, so it is priced after the source has been found. A fixed figure for every pool would be a guess. Where the leak is in the surface and the answer is a full re-finish, the price is one overall price. As a guide, a remarbelite on a 6×4 pool is about R18,000 and a refibreglass on a 6×4 pool is about R25,000. Minor work such as a light change or a sand change is included in the overall price of a major job. Ask for a written quote once the source is confirmed.

Suspect your pool is leaking? Call 081 537 0757 or email sales@trademen.co.za for a free quote anywhere in Gauteng.

For more background, see this external overview of swimming pool systems.