Repairing Your PondThere are few things guaranteed to make the pond-keeper feel sick quite so quickly as the sight of the water level suddenly starting to drop for no good reason. Any one of a number of other causes may be to blame but the automatic fear is a leaky liner – and the necessity of making a repair, which is never a job to be undertaken lightly. Fortunately, however, in many cases fixing a holed liner can often end up being far less difficult than you might think, particularly since modern glues, patches and repair kits are much improved over earlier versions.

Having eliminated losses from leaking pipes, natural evaporation, splashing fountains and waterfalls and other possible causes of the diminishing water level – and facing the inevitability of a repair – the first thing to do is to find the leak. While this is not always a straightforward job, the good news is that it is often not necessary to be thinking in terms of finding emergency quarters for your precious fish and then draining the whole pond. The simplest and certainly least traumatic way of tracking down the hole is to do nothing and let the water settle to its own level – which will, of course, be just below the leak – making the area which needs to be to be painstakingly examined for punctures much smaller.

Fixing the Leak

For the two most common types of garden pond construction – those using either flexible or pre-formed liners – repair kits are readily available. Repairing PVC, butyl or EPDM flexible liners generally involves either applying a length of flexible, high-adhesive tape to the split or hole, or using specialised glues to fix a watertight patch. Locating the hole is usually fairly easy given the smooth appearance of the liner material, but it can be complicated by the creases which occurred when it was first laid; a split under a fold can take some finding! Leaks from pre-formed pools fortunately seem to be quite rare. However, accidents can happen and resin-based repair kits are available from a variety of manufacturers to make good the damage in the case of a fibreglass pond, while polyester or polyethylene versions are available for those made of HDPE and other plastics. These kits contain all the materials needed to make the necessary repairs quickly and easily.

Unfortunately holes in ponds made from the less commonly used materials such as concrete and resin coated block-work are less easily found and appropriate quick repair kits are not to be had. Often the only practical solution with either type of material is to remove the pond-life to alternative accommodation, drain the pond and then recoat with sealant or resin to make the structure watertight again. Alternatively, if this is shaping up to be too big or costly a job, a new flexible liner can be fitted, over a suitable protective layer of sand, newspaper or purpose made underlay.

As with so many aspects of pond keeping, a little bit of prevention at the outset is better than being faced with having to fix a problem later and many of the common causes of leaks can be avoided if the pond is installed properly in the first place. If the liner is fitted in accordance with the manufacturer’s instructions, in a properly excavated hole, free of stones and roots and protected by a sufficiently deep layer of cushioning material, there should be no reason why it should not last way beyond the lifespan of its guarantee. However, it is easy to be wise after the event and all of this is scant consolation if your pride-and-joy pond has, for whatever reason, sprung a leak. While this is never good news, there are ways to fix it and – with luck – without too much disturbance and upheaval into the bargain.

Keeping the area around your pond clear of debris is important because sharp objects like twigs or stones can puncture the liner or cause abrasions that weaken it over time. Fallen leaves and other organic matter can also create acidic conditions that may degrade the liner, particularly if they are allowed to accumulate and decompose over a long period of time. To prevent these issues, it’s a good idea to regularly remove any debris from the pond and surrounding area, particularly in the fall when leaves are more likely to accumulate.

In addition to maintaining the area around the pond, it’s important to monitor the water chemistry of your pond to ensure it is within appropriate ranges. For example, if the pH of the water becomes too low or too high, it can weaken the liner and make it more susceptible to damage. Similarly, high levels of ammonia or nitrites can also lead to liner damage over time. To prevent these issues, it’s a good idea to regularly test the water in your pond and make adjustments as necessary to maintain appropriate levels. This might involve adding pH buffers or performing partial water changes to reduce levels of pollutants.

By taking steps to maintain the area around your pond and monitor water chemistry, you can help prevent leaks and extend the lifespan of your pond liner. Regular maintenance and monitoring can also help identify potential issues before they become major problems, which can save you time and money in the long run.


  • Finding a leak in a pond can be a difficult and stressful task, but fixing a holed liner can often be less difficult than expected with modern repair kits available.
  • For flexible or pre-formed liner constructions, repair kits are readily available, while repair options for less common materials such as concrete or resin coated block-work may require draining the pond and recoating with sealant or resin.
  • Proper installation, such as following the manufacturer’s instructions and using cushioning materials, can prevent many common causes of leaks in the first place.
  • Maintaining the area around the pond and monitoring water chemistry can also help prevent leaks by removing sharp objects, debris, and maintaining appropriate pH and pollutant levels.
  • Regular maintenance and monitoring can help identify potential issues before they become major problems, saving time and money in the long run.
Last Modified: April 5, 2023