Technical FAQ hub

Pool Water Loss FAQs

Clear answers for homeowners, estates, body corporates and insurers dealing with swimming pool water loss.

Detection before digging

Pool Water Loss FAQs

We locate the exact source of water loss using pressure testing, dye testing and tracer-gas methods, so the leak is confirmed before anyone breaks paving or digs.

Our approach is deliberately non-destructive. We test before we touch anything: suction and return lines are pressure tested, fittings and cracks are dye tested, and underground runs are checked with tracer gas. Only once the leak is confirmed do we recommend opening anything, and only at the exact spot the evidence points to.

Why act early

A leaking pool in your area does not stay the same size. Water escaping underground washes out fine soil, softens the ground and can undermine paving and coping over time. Finding it early is almost always cheaper than waiting for visible damage.

How we find it

We work by elimination. Each possible leak path, suction line, return line, light, weir, crack, surface or fitting, is tested and either ruled out or confirmed. That produces a defensible finding you can act on, and a quote scoped to the real problem instead of a worst-case guess.

Is it a leak or evaporation?

Not all water loss is a leak. A small daily drop in hot or windy weather can be ordinary evaporation. The difference is consistency: a leak keeps losing water even in cool, still conditions, and often drops to a particular level and then slows. Testing is the reliable way to tell the two apart.

Common signs of a genuine leak rather than evaporation in your area include:

Why homeowners and estates choose us

Where you need documentation, for an insurer, a body corporate or an estate, we can provide a written report covering the inspection, the test methods, the findings and the recommended repair.

Send your address, the pool symptoms and a short video or photos of the water level and pump. We will come back to you with the likely cause and what the visit involves.

How much water loss is normal in a swimming pool?

Normal water loss depends on temperature, wind, humidity, pool exposure and how much the pool is used. A small daily drop may be evaporation, especially in hot or windy weather, but a consistent or sudden drop should be investigated. If the water level falls quickly overnight, falls below fittings, or requires constant topping up, it is safer to treat it as a possible leak rather than assuming evaporation.

How can I tell the difference between evaporation and a leak?

Evaporation normally changes with weather conditions and affects most exposed pools in a similar way. A leak is more consistent and may continue even during cooler weather. Warning signs include water dropping to a certain level and then stopping, air entering the pump, wet paving, soft soil, recurring algae from dilution, or a water bill that increases without another explanation. Professional testing is the reliable way to separate evaporation from a true leak.

Why is my pool losing water overnight?

A pool that loses noticeable water overnight is less likely to be losing water only through evaporation. Overnight loss often points to a structural leak, leaking fitting, suction leak, return pipe leak, light niche issue, weir defect, crack, porous marblelite or fibreglass pinholes. The correct approach is to test the shell and plumbing separately so the repair does not target the wrong area.

Why does my pool lose water when the pump is running?

Water loss that becomes worse while the pump is running often points to the pressure side of the circulation system. This can include return pipes, aimflow fittings, valves, filter connections or pipework under paving. When the system is under pressure, water can be forced out through a crack or failed joint. Pressure testing helps confirm whether the line is holding or losing pressure.

Why does my pool lose water when the pump is switched off?

If the pool loses water while the pump is off, the leak may be in the shell, light, weir, main drain, crack, porous surface or a pipe section that remains water-filled without pump pressure. Dye testing around fittings and structural defects is often useful because dye may be pulled directly into an active leak path.

Can a pool leak only at a certain water level?

Yes. A pool may drop until it reaches the level of the leak and then slow down or stop. This often happens with leaks at lights, weirs, return jets, tile lines, cracks or surface defects. The stopping level is an important clue because it tells the technician which fittings and areas require closer dye testing.

Can a swimming pool leak underground?

Yes. Underground suction and return lines can leak due to failed joints, ground movement, age, poor installation, root movement or previous repairs. These leaks are usually not visible from the surface and may only show as wet soil, sinking paving, air in the pump or unexplained water loss. Pressure testing and tracer gas can help narrow down the underground failure point.

Do all underground leaks require excavation?

No. Excavation should only be done after testing narrows down the likely leak area. Opening paving or concrete before testing can waste money and create unnecessary damage. The correct method is to isolate the affected line, confirm pressure loss, locate the likely section and then open only where there is evidence to justify it.

Book Pool Leak Detection

Pool Leak Detection Qualification Form

Please complete the details below so we can qualify the leak properly before dispatching a technician. The inspection fee covers leak detection and diagnosis only. Repairs are quoted separately after testing.

Important: Pool Leak Detection Pros is based in Gauteng. Service charges outside Gauteng are generally higher because of travelling distance. Photos and videos should be sent on WhatsApp after submitting the form.
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By submitting, you confirm that the information supplied is accurate enough for initial qualification. Final diagnosis depends on inspection and testing on site.