Common Causes Of Pool Leaks

Common Causes Of Pool Leaks - What Are They?

Has your swimming pool recently developed a leak and you’re wondering what could have caused it?

In this article, we take a look at the most common causes of pool leaks. There’s more causes than you might think and chances are, your leak originated with one of these.

It helps to take a look at these potential causes and narrow down the possibilities before getting in touch with a leak detection specialist.

Let’s get started!

Common Causes Of Pool Leaks

Damage To Pool Surfaces

This is the one that everyone thinks of first when the topic of pool leaks comes up. To be fair, it does cause the lion’s share of leaks.

Cracks In Concrete

The constant exposure to water, sun, and chemicals can cause a pool's concrete surface to crack over time. This can lead to leaks, which will get larger and worsen over time if not promptly repaired.

This is because water flowing through the crack will further erode the concrete. In some cases, the pool may need to be fully resurfaced to prevent further damage.

Damage to Vinyl Liners

Vinyl liners are a popular and affordable option for pool surfaces, but they are susceptible to tears, punctures, and other types of damage.

Once a vinyl liner is compromised, water can leak out of the pool and the liner will need to be repaired or replaced, which while cheaper than conventional resurfacing, can still be costly.

Wear And Tear Over Time

Even with proper maintenance, a pool's surfaces will eventually deteriorate with age. Fibreglass, pebblecrete and other pool surfaces will all experience the effects of ageing, and can develop leaks.

Regular inspections can help catch minor issues before they become major (and expensive!) leaks.

Equipment Failure

Leaking Pool Pump Or Filter

A pool's pump and filter work together to keep the water clean and clear, but if either of them develops a leak, water can escape from the pool. This can be caused by worn-out gaskets, seals, or O-rings.

The piping in and out of your pool equipment is often underground and full of water at all times. Any cracks or leaks in this piping - or the joints connecting the piping to the equipment - will lead to water seeping out of your pool.

Cracks In Pool Heater

Pool heaters are exposed to variable temperatures and corrosive pool chemicals, which can cause cracks to develop over time.

A leaky pool heater can not only cause water loss but also can waste electricity and pose a safety risk.

Malfunctioning Pool Light

Pool lights are fully submerged at all times. They can leak water into the light fixture if they become loose or damaged. This water can then travel along wiring and into other cavities, resulting in a leak.

Ground Movement

Soil Erosion

Over time, soil erosion can cause a pool to shift and settle, leading to cracks and leaks in the pool structure or shell. This can be caused by factors such as heavy rain, poor drainage, a high water table, or even nearby construction.

If your pool is built partially out of the ground, ensure that the surrounding soil is adequately supported and compacted to prevent run off in heavy rain.

Structural Issues

Shifts In Foundation

A pool that was built on an unstable or shifting foundation can experience cracks and leaks over time. This can be caused by factors such as soil subsidence, improper drainage, or inadequate site preparation.

Your pool builder should have identified this possibility during construction and taken steps to reduce the likelihood of foundation shifting.

Structural Damage To Pool

Damage to the pool's walls, floors, or coping can cause leaks. This can be caused by factors such as accidental impact or harsh weather conditions (think heavy hail).


As you can see, there are a wide variety of potential causes of pool leaks. In fact, when you think about it, it’s amazing that most pools are even water-tight in the first place!

In any case, vigilance, early detection and early action are key for preventing a small leak from becoming a major problem.

If you are in any doubt, get a leak detection expert to check out your pool. It may cost a few hundred dollars, but it may also end up saving you tens of thousands of dollars!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.