Understanding How To Seal A Pond Naturally

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When you see the water level of your pond depleting slowly, you might ignore it or even think it’s due to evaporation. Well, just to make you aware, this might not be the case. There are various reasons for your pond to lose water. It can be due to a poorly constructed pond bottom, messed up liner, or even seepage. Whatever the cause may be, the outcome is a dry, waterless pond, which isn’t a good sign for life inside it.

Once you are sure, you can quickly look for different solutions on how to seal a pond naturally.

There are specific ways by which we can determine if the pond is losing water due to leakage or not. Read below to know everything about pond leakage and how to seal it.


Understanding Seepage

When water escapes from a porous surface such as soil with some amount of voids due to the presence of air, it is known as seepage.

This can occur in almost any water body but here we will explain how to reduce it in the context of ponds.

Pond Seepage Control

Excessive seepage of a pond can lead to a very serious problem for the inhabitants living underwater. This occurs due to various reasons - permeable soil or bedrock and highly permeable residual rock layer.

If proper measures are taken you can reduce the seepage of water from your pond permanently. Here are a few methods by which you can control seepage of water from the beginning.

1. Bentonite

Bentonite is a clay with a high capacity to hold water. It is mixed with the soil present on the foundation of the pond in specific layers. When contacted with water, this clay swells to many times its dry volume, which helps it stay intact and doesn’t let the water seep through it.

Did You Know?

There are two varieties of bentonite. However, only sodium bentonite should be used for ponds and other water bodies such as a reservoir.

2. Securing With Membranes

Highly flexible membranes can be used on the foundation of the ponds, for example, polythene, PVC, rubber membranes in order to prevent water from seeping through the soil.

How to Find Out if Your Pond is Leaking?

It can be a little tricky to find out the exact point from where the water might be leaking at first. Still, with these simple steps, you can easily determine what is causing the water to leak.

Did You Know?

Small cracks, if they remain unattended, can further damage the bottom of the pond and cause to be fatal for the pond’s ecosystem.

1. Check for Spill along the Bank

If you notice damp areas around the pond, you might want to check if the liner’s position has slightly changed. This can also happen if the landscape rocks have shifted to a different side.

Fill the pond up to a favorable point and then check if the water is spilling out or if the edges are damp. If this doesn’t solve the problem you might want to check the other options.

2. Turn Off the Pump

It is important to turn off the equipment of the pond while checking for any leakage. First things first, turn off the pump. If you notice the leak, there might be a crack or tear in the liner or foundation. On the other hand, if you do not notice any leakage then it is definite that the problem is in the equipment.


Pond Sealing - Natural Methods

If you have confirmed that your pond has a leak, then you need to seal it as soon as possible to stop further breaching of water. For this, you would require a sealer that is used to fix small holes or cracks. Further, this is depending upon the foundation of your pond - whether it is a liner, a concrete foundation, or a soil/clay foundation.

1. Pond Liner Sealant

You might have two options in order to repair your pond liner, draining the pond and the other one is to avoid this step.

Pro Tip

While examining if you feel that the tear will not be fixed by a sealant consider replacing your liner.

  • Underwater Pond Liner Sealant

    An effective way to fix a tear without having to drain your pond would be an underwater pond liner sealant. This is applied directly to the tear after cleaning the tear thoroughly. Liners made from any type of material such as PVC or plastic can be fixed with this particular sealant. This product uses moisture as an ideal environment for fixing the crack.

  • Pond Liner Patch Kit

    Drain your pond for up to at least 6 inches below the tear in order to use this kit and remove any tears on the surface of the liner.

    A patch kit includes a solvent wipe, scrub sponge, patch, and a seam roller. To start the procedure you need to first clean the area surrounding the tear with a solvent wipe. After that scrub the area with the help of the scrub sponge. You will find a backing paper on the patch. Remove the backing paper it and put the patch over the tear. Now, with the help of a seam roller apply pressure to the patch and the tear will be fixed.

    To repair minor tears on the liner, click here to buy an effective Patch Kit.
​Kit For Minor Repairs & Tears - Recommended
  • materials in this kit are well made
  • Soft, easy-to-use
  • patch material is thicker, softer, and more durable ​

2. Concrete Pond Sealer

Ponds made from cement develop cracks over a period of time. These may be durable but seem to be the most common type of pond foundations to have cracks developed on them. Sealing a concrete pond is different than sealing a pond with liner. Here are some ways to seal a concrete pond.

  • Pond Liner Patch Kit

  • Epoxy sealants build a highly protective film on a concrete surface and are designed to prevent cracks from being formed. It works by gluing the cracked surface back together and can be used for a wooden foundation as well.

     Click here to buy Pond Shield Epoxy Paint, an amazing waterproof formula to seal ponds!
Water proof formula - Best Choice
  • suitable for use in a wide range of climatic environments
  • reliable adhesion for a finished surface that is easy to maintain
  • Can be applied to any constructed surface made of wood metal or stone

3. Bentonite Sealer

Bentonite is a natural clay pond sealer. When exposed to water it expands up to 15 times and creates an effective seal in a cracked surface. Keep in mind that bentonite should be sprinkled directly on the cracked surface only when the pond is dry. It does not work immediately but takes a few days and slowly seals the leak. Also, it may not work well in ponds which seem to have extremely well level fluctuations.

4. Chemical Additives

Various chemicals can be added to the soil in order to improve its water holding capacity. This method proves more effective when added to soil with a high percentage of clay. These chemicals break the soil into smaller components and shifts the soil’s structure to adjust accordingly. The most common chemical additive is sodium polyphosphate. It should be mixed to the top 8 to 10 inches of soil with appropriate equipment.

5. Plastic Liners

Whilst sealing a pond plastic or vinyl liners can be used. Liners are much more expensive than other methods but provide a sure shot solution to a leaking pond. They are effectively used in small ponds where severe leaks occur frequently. However the only drawback of liners is that they are prone to punctures or tears, therefore they should be covered with 9 inches of soil.

6. Using Lime

Sealing a pond with lime helps to bind the soil when added in an adequate amount and creates lime concrete. It is permeable are doesn’t allow seepage of water. You can also cover it with clay and block direct contact of lime with water thus preventing it from turning alkaline. Once you have completed the sealing job, do not put water immediately. Give it some time to start the binding process.

It is indeed one of the cheapest ways to seal a pond.

Did You Know?

Lime is a versatile mineral and can be used in environmental, chemical or industrial applications.


Pond Sealing - Artificial Method


Compaction is a method by which soil is rearranged by applying pressure and the air between the particles is released. It can be achieved by using heavy-duty machinery like rollers. This prevents the water from leaking after the pond is filled.

Video Introduction

Prevention is Better than Cure

Once you have learned how to seal a pond naturally and are also aware of the artificial methods, you will realize that they are a foolproof solution to a leaking pond. However, they take more time and involve a considerable amount of effort and expense. Therefore, prevention is undoubtedly always better than cure.

These sealing methods prove to be more effective during the construction phase and require less maintenance once they are taken care of since the beginning.

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