How to find and repair leaks in garden pond liners.

Can a leak in a pond be fixed?

Yes.... Leaking concrete ponds, preformed liners, rubber pond liners, plastic liners and clay lined ponds can all be repaired. Whilst leaking rubber and plastic liners can be fixed I would normally recommend replacing them especially if they are a few years old. 


I have included some easy to follow Diy instructions on this page.

This leak is simple to fix
This one was simple to fix

How to trace a leak in a garden pond

 This works for rubber pond Liners, ponds made from clay and concrete lined ponds.

In the warmer months you will get some water loss due to evaporation and splashing from water features like fountains and waterfalls, but once you have discounted this and have a significant or sudden loss of water you will need to find the leak.

To check the leak is actually from the pond and not the stream or waterfall or more likely the plumbing, saving time and maybe cost follow the steps below to find the leak.  


Checking the main pond for leaks.

Turn the pump off, if the water level continues to drop the leak is almost certainly from the pond and not the plumbing or water-features so skip the full plumbing/water-feature check outlined below, (it may be worth a partial check of the plumbing/water-feature with the pump on once you have fixed the leak in the pond just to be sure). Providing the level isn't dangerous to fish, (plants will survive a couple of days without water) allow the pond to continue to leak until it stops and mark the level all around the pond with chalk.  

When the water level has stopped look closely all around the chalk line for any damage.

  • Leaks in rubber liners this could be a large gash or even a hard to see tiny pinprick.
  • Leaks through concrete  could be cracks or deterioration of the concrete. In older or poorly constructed ponds this might be visible over much of the concrete lining. 
  • Leaks in Clay will be through cracks that are not always easily visible and are mainly caused when the water level is allowed to drop allowing the clay to dry out or by root damage.  


Now check the plumbing and water-features. 

  • Turn off the pump.  If the water level stays the same in the main pond this almost certainly means the leak is either from the plumbing, the waterfall or the stream and not the pond.  Check the joints in the plumbing and replace or tighten up any loose or broken joints or bits of pipe.
  • Once you are sure it is not the plumbing check the waterfall and stream for leaks and for a simple overflow overflow caused by plants or other obstructions raising the water level. The easiest way to check for overflow over the liner edge is to check around the perimeter for wet spots and remove the obstruction. A wet spot may also simply mean that the edge of the liner has fallen below the water level, pull the liner up and pack under it.
  • Cant find a visible leak in the plumbing, stream and waterfall or pond. Occasionally, where the waterfall and pond have been lined with separate sections of liner instead of a single continuous liner running under the waterfall into the pond you could end up with water leaking under the construction, somewhere between the two liners. This is a fairly major fault to repair and will mean dismantling the waterfall to find and remedy the problem.  Adjust/fix the joint/overlap in the liner or replace the complete liner.


The simplest way of finding the leak and this applies to all types of pond liners, is to let the water settle to its own level, which will be just below the leak and mark the area with chalk.

Diy tips and equipment to repair leaks in garden ponds.

Now that you have traced the leak let's look at the different techniques and equipment you will use to fix the leak. Leaks in rubber and plastic are mostly about patching with waterproof materials whilst concrete and clay liners are more about filling and blocking the leak. We will look at these one by one.........starting with fixing leaks in rubber liners.

How to repair a leak in rubber pond liners


This  Rubber Pond Liner Repair Kit  is ideal for punctures and tears causing leaks in your Garden pond Liner. 

Works on  PVC, Butyl Rubber, Butyl Epalyn, EPDM and Firestone.

Can be used to Fix all leaks in rubber pond liners, Durable and lasts many years and is easy to use works like a sticking plaster

Works Underwater

100% Non-Toxic and fish friendly

Unlike similar "quick fix kits" this kit is very easy to use, just follow the full list of instructions provided and you can't go wrong. You will need this underwater Sealant to stick the patches on. The Pond and Aquarium Sealer is a fish safe sealer that can be used underwater for instant repairs, Solvent & Isocyanate Free, Bonds all surfaces and is Ideal for Butyl Rubber, Vinyl, Glass, Plastic, Ceramic, Stone, Concrete and more


How to repair a leak in a clay pond

Bentonite For Sealing Ponds:

Sodium Bentonite Seals and repairs leaks in clay ponds, waterfalls and streams.


How it works. The granules swell up to eighteen times its dry size when it becomes wet and forms an impermeable gel seal which makes an excellent pond sealant. 


Bentonite for sealing clay ponds:

When properly applied it is environmentally safe and does not affect the water, fish or pondlife.  Also makes an excellent liner for new clay pond construction.


How to seal a leak in a clay pond.  

  • Bentonite can be applied directly to the leak in the clay in the pond.  
  • Or it can be sprinkled on the surface of the water and allowed to follow the flow of the water into the leak, where it expands making a watertight repair. Full instructions come with the pack.

 Bentonite is easily applied. In the case of garden clay ponds, it can be applied with simple hand tools and for larger ponds, with ordinary farm equipment. Follow the instructions.

How to repair a leak in a concrete pond

Repair kit for all leaking concrete lined water-features including garden ponds, streams, waterfalls and bird baths.

It Seals leaks in concrete ponds  by forming  A Non-Porous Seal  


I recently fixed a clients leaking waterfall with this, the water feature was losing 4-6 inch's of water everyday, it took 3 coats and completely stopped the leak.


I have also applied it by pouring directly into a clean and dry pond and then spreading it and painting it around with a brush.

But I recommend following the full set of instructions that come with it. Mike


We repair or fit replacement liners in 

Somerset, North Somerset, Bristol, Clevedon, Portishead, Nailsea, Weston-super-mare, Yatton, Sreeet, Wells and Glastonbury. Contact