Repair Pond Liner: Find and Repair Holes in the Liner

Repair pond liner: Find and repair holes in the liner

If your pond loses a lot of water, it may be due to a broken pond liner. Various influences can lead to damage to the pond liner. This can also happen due to a moment of inattention during pond maintenance. High water loss does not always have to be due to a damaged pond liner. Before pumping out the water and looking for defects on the pond liner, consider whether the water loss may have other causes.

Your Pond is Losing Water – Various Causes

A hole in the pond liner can only be one cause if your garden pond is losing water. When it is very hot and the sun is intense, water loss is entirely normal in summer. The water evaporates. The water level can decrease by several centimeters within one day. A daily water loss of ten centimeters is not uncommon. Transpiration from plants also causes water loss on hot summer days. You should shade your pond with a parasol or awning and then check if your pond is still losing a lot of water. You should replenish the water regularly on hot summer days.

If you have added a stream or fountain to your pond, this can also cause water loss. Especially on windy days, the pond can lose water. The wind carries the water out of the pond drop by drop. Your pond can lose several gallons of water a day this way when it is windy.

Decorative materials such as plant bags, stone sheets, or reed mats can also cause water loss. The culprit is the capillary action of these materials. Like a candle wick, such decorative materials draw water out of the pond. If such materials do not end within the liner seal, the water drawn in cannot get back into the pond. Connections between the pump and filter or stream can also cause water loss if they leak. Over time, such links can become loose. Leaks can also occur if the connections were not made correctly in the first place. The water then seeps into the ground unnoticed.

Before you remove the water from the pond and check the pond liner for damage, you should consider whether the water is lost through such weak points.

But if the Liner Now Has a Hole

If you have considered all possibilities for water loss and your attempts to limit water loss have been unsuccessful, a hole in the pond liner may be the cause. It can be pretty costly to track down the defective area in the liner. Pumping out and clearing out the pond can involve a lot of work, especially if there are many plants in your pond. Bottom soil and rocks will also need to be cleared out so you can find the leak in the liner.

Locate the Hole

Before you go through such an effort, you should locate the hole. This may take some patience, but it is efficient in the end. It would help if you filled the pond to the brim with water. Using chalk, mark the water level every day. If the water level stops dropping, you have reached the water level where the hole is located. If the water level drops to a low level, you should relocate your fish in time so that they do not suffer any harm. To do this, you should have a large tub of water ready. You now need to check in the area between the chalk mark and the water level where the hole is located. If you have a large pond, this can be pretty involved as well.

How to Uncover the Leak

What you need now to locate the leak is a pair of sturdy rubber gloves, rubber boots or waders, and a cloth. You will need to feel the liner for damage in the area between the mark and the water level. Holes in the pond liner are often caused by rocks, broken glass, or other sharp objects. You can feel such damage. Roots of plants located in the riparian zone or at the edge of the pond can also cause damage to the liner.

What you Should Pay Attention to During the Repair

Once you have found the damaged area in the liner, you can start repairing it. This only makes sense if the pond liner is not too old. The old pond liner is firmly hardened and no longer flexible enough. The repair with a patch is no longer efficient, and the subsequent leakage in the liner is then already pre-programmed. In such a case, only one thing helps: Replace the liner completely!

If the film is not yet so old and is still flexible enough, you can repair it with a patch.


Already when you create your pond, you should buy enough liner and leave a piece for possible repairs. To avoid damage to the foil, you should work as wrinkle-free as possible.

Now You’re Ready to Go!

If the liner is still flexible enough for repair, you should remove the water to a level where you can work comfortably. It would be best if you cleaned the place where the hole is located from algae and dirt. This is the only way the glue will hold. Once you have repaired, the adhesive must cure before you fill the pond with water again. This will take at least 48 hours.

To repair the pond liner, you will need a pond liner adhesive and a patch of pond liner. If you have not left any liner from creating the pond, you should purchase a liner for the repair. You should ensure that the foil for repair is the same thickness, quality, and color as the existing foil.

Very Important: The Special Glue for the Foil

The adhesive for repairing your film must be permanently elastic and have a high initial adhesive strength. The repair process is therefore also known as cold welding. Apply the adhesive according to the instructions.

How You Proceed With the Repair

To ensure that the patch holds and does not immediately cause a new leak, it should overlap the leak by about 6 to 8 inches (15 to 20 centimeters). Once you have applied the adhesive and applied the patch, let everything cure. Then, let water back in and put the fish in the pond. Now there should be no more significant water loss.

What to Look for in Rubber Sheeting

Rubber liner (EPDM) is not so easy to repair. You will need several adhesives. With a special basic cleaner, you need to work on the film. On the dry rubber film, you apply a bonding agent. Now you use double-sided tape on this bonding agent. This tape must be permanently elastic and designed for EPDM. Place the foil patch on this adhesive surface. A wallpaper roller will help you to press this foil patch down hard.

Repair With Liquid Pond Liner

A liquid pond liner based on polyurethane allows for easy repair. It adheres to almost all substrates. However, it is not suitable for PE films. You should spread the liquid film over the defects with an overhang of about 8 inches (20 centimeters). You should fix a giant hole with armor tape before applying the liquid film. The film should be allowed to dry thoroughly between coats. This stabilizes the weak spot. New holes are prevented.


If your pond is losing a lot of water, it can be caused by many things. Before you repair the pond liner, you should check to see what is causing your pond to lose water. Using a chalk marker and waiting to see how much water the pond loses, you can track down the leak. It would help if you kept the fish in a separate tank. Once you have found the leak, you can repair it with a liner patch and a special adhesive. If the foil is getting on in years, fixing it is not a good idea. You should then replace the foil completely.

Florian Egert

I am Florian Egert, the owner of I live with my wife and two children in Germany in a small village in the countryside.

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