Common pool leaks and what causes them

Pool leaks are more common than many homeowners realise – and they’re not always easy to spot. While some leaks are visible, others occur below ground or within the pool structure itself, leading to ongoing water loss, higher utility bills, and potential damage if left untreated.

Below, we explore the most common pool leak areas, how to identify them, and what typically causes them. Understanding these problem areas can help you act quickly and decide when professional leak detection is needed.

Skimmer to pool bond

Leaks often occur where the skimmer meets the pool wall, particularly in concrete pools.

Perform a dye test near the skimmer and watch for water being drawn into cracks or gaps.

Soil movement, separation between the skimmer and pool shell, or poor installation.

Underground plumbing

Underground pipes can crack or break, resulting in significant water loss that isn’t immediately visible.

Look for wet patches, soft ground, or soil erosion around the pool area.

Ground movement, pipe corrosion, or incorrect installation.

Pool light niche

Leaks often develop around the conduit or outer ring of the pool light.

If the pool water level consistently stabilises at the height of the light, it may indicate a leak at the niche.

Faulty seals, poor-quality fittings or equipment, incorrect installation, or ground movement.

Return jets

Leaks can form where the return jets connect to the pool wall.

Conduct a dye test around each return jet to check for water movement.

Loose or damaged fittings, deteriorated seals, poor quality materials and installation, or cracked return lines.

Tile and coping

Cracks along the tile line or coping can lead to gradual water loss, especially in older pools.

Visually inspect for cracks, gaps, or loose tiles, or use a dye test along the waterline.

Ageing materials, weather and chemical exposure, or structural movement.

Pool shell cracks

Cracks in concrete or fibreglass pool shells can allow water to escape.

Visually inspect pool walls and floors, or use a dye test on suspected cracks.

Ground movement, ageing materials, or structural stress.

Skimmer cracks

Over time, skimmers can develop cracks due to constant exposure or movement in the pool structure or surrounding soil.

Use a dye test around the skimmer body to see if water is being drawn into cracks.

Soil movement, ageing plastic, or improper installation.

Multiport valve

Leaks often occur at the multiport valve on sand filters.

Check whether water is trickling from the waste line while the pump is set to filter mode.

Worn valve seals or incorrect positioning after backwashing.

Equipment pad

Leaks at the equipment pad usually involve pumps, filters, or valves.

Inspect for puddles, damp patches, or dripping water around equipment.

Loose fittings, worn seals, or corrosion.

Heater connections

Leaks can develop where the heater connects to the pool plumbing.

Look for moisture or pooling water near the heater connections.

Loose fittings, worn seals, or corrosion within the heater’s internal components.

Plaster finishes around outlets

Marbelite or similar plaster finishes may not bond properly around PVC outlets.

Perform a dye test around outlet fittings to detect water movement.

Poor bonding or detailing between new plaster and existing outlets, combined with prolonged exposure to imbalanced water chemistry.

Pressure-side plumbing

Leaks on the pressure side of the plumbing (after the pump) can result in noticeable water loss.

Monitor water loss when the pump is running or listen for the sound of escaping water along the pool and equipment pad perimeter.

Cracked pipes, damaged or inferior-quality pipes or fittings, poor workmanship, or soil movement.

Suction-side plumbing

Suction-side leaks occur before the pump and often introduce air into the system.

Check for air bubbles in the pump basket or return lines.

Loose fittings or cracks in suction-side pipes and connections.

Pool steps

Cracks or separations around pool steps are a common but often overlooked leak source.

Inspect the base and sides of steps for visible cracks or gaps.

Ageing structures, ground movement, or poor installation.

Filter tank seals

Leaks around sand filter seals are a frequent maintenance issue.

Look for moisture, dampness, or visible cracks around the filter tank.

Worn or damaged seals due to age or incorrect installation.

When to call a professional

If you suspect a pool leak but can’t pinpoint the source, professional pool leak detection can save time, water, and costly repairs. Specialists use advanced testing methods to locate leaks accurately without unnecessary damage to your pool or surrounding area.

Suspect a leak? Let us help.

Our specialised pool leak detection service uses non-invasive techniques to accurately locate leaks and advise on the best next steps.

Visit our Pool Leak Detection page to learn more. Click the button below:

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