How to fix a leaking pond with bentonite

How to fix a leaking pond with bentonite

To fix a leaking pond with bentonite, the process is quite simple. Take the bentonite and sprinkle it over the surface of your pond. So, where’s the trick? It can’t really be so simple, can it?

Well, is not. Most of the work that will assure the success of sealing your leaking pond is done before you even buy the bentonite. There are some things that you need to know before you just go out, buy 50 lbs of Pond Sealer and throw them on the water. Let’s get to it.

farm pond with bentonite pond liner

Granular Bentonite Pond Sealer vs Powdered Bentonite Pond Sealer

For starters, bentonite can be milling in different grain sizes. Does the grain size matter? It does, as depending on the grain size is how you should apply it. Granular Sodium Bentonite Pond Sealer (coarser grain size) is used for “wet” applications, for ponds or lakes that can’t be drained, or for sealing wells and water treatment plants. Powdered Sodium Bentonite Pond Sealer (finer grain size) is usually used for “dry” applications when the pond has been drained or is almost completely dry.

Photo Sep 20, 1 45 30 PM

Fix a leaking pond with bentonite – “Wet” Applications

Usually, when our clients contact us asking if we can fix a leaking pond, it’s because they are losing water rapidly and they can’t really afford to keep losing this precious resource. In those cases, we need to act as soon as possible to try to prevent the leakage

  1. The first thing we should do is try to locate the leak. Do you know where the leak is? Is it possible to locate a single point of leakage?
  2. Depending on the answer to question number one, we will determine the surface area that will be required to be sprinkled with bentonite. It can be partial or the whole pond. Obviously, the chances of successfully sealing the leak in the pond are higher when the whole pond is sealed, but it may not be necessary in your particular case.
  3. Determining the amount of bentonite needed to successfully seal the leak will require to know the type of soil of your pond. Porous soils require a higher concentration of bentonite to seal any leaks. In this article by Peak Prosperity, you can find a quick and easy way to determine if your soil is porous or not.
  4. Now is the time to buy the bentonite pond sealer. We invite you to keep Lonestar Barite in mind as a possible supplier, we provide high-quality bentonite (each batch tested) and we deliver nationwide.
  5. Depending on the size of the pond, the bentonite can be sprinkled manually or be spread over the water using a pump. This method is called the Sprinkle Method.
  6. Hands on! Once we have determined the area, the amount, the method to be used and we have the bentonite at our location ready to be applied, it’s time to proceed with the application, making sure it is evenly spread out throughout the area to maximize the chances of success.
sprinkle method for Bentonite pond sealant

Fix a leaking pond with bentonite – “Dry” applications

When we are called in to fix a leaking pond where the leak has drained almost all the water out of the pond or lake, it is usually because of a leak on the hillside or slope, sometimes very near the bottom of the pond. In those cases, mixing the bentonite with the dried soil around the edges of the pond is what usually works best.

  1. Using the evidence of the height of the water when your pond is full, determine the area in which we will apply the bentonite pond sealer. You can use our bentonite pond sealer calculator as a reference.
  2. Knowing the type of soil at the bottom of the pond is crucial to determine the amount of pond sealer that will be required for the job. Keep in mind that the more porous the soil, it will require a higher concentration of bentonite pond sealer to seal any leaks.
  3. Depending on the size of the pond, the bentonite can be spread over the slopes of the pond or it can be mixed into the soil in the slope.
  4. It’s time! Once we know the area, the amount and the method to be used, we proceed to the application process, attempting to create a homogenous blanket throughout the area to maximize the chances of success.

While the application of pond sealer to dry soil has higher chances of success, it also tends to be a bit more expensive because of the preparation the soil needs to receive the bentonite. “Wet” applications are least certain in their results, but if the farm pond leak is very well defined and located, it can be an effective solution.

pond liner bentonite


Why use bentonite and not another type of product available in the market?

Bentonite is natural clay. No chemicals are added to it. That makes it the safest and most effective product for your pond to remain full for many years to come. No livestock, wildlife, fishes or plants will be harmed by the addition of bentonite pond sealer to your pond.

If I can’t find the leak, do I need to seal the whole pond?

Unless you have a very specifically located leak, for example, a hole in a rubber liner made by the root of a tree or a hole in a dam made by a beaver, it is recommended to seal the whole pond to make sure any possible leaks are sealed. Of course, sealing the whole pond is always a better bet than sealing just a specific area, but each case is different. Our experts can approximate your odds of sealing a leak in your farm pond by applying bentonite only to a specific area of your pond.

What can I expect after the bentonite pond sealer is applied?

It takes about a week for the bentonite to achieve its maximum hydration state. In 3-5 days, the water level should stabilize and after that period, in some cases, it will raise.

How long can I expect for the seal to last?

If correctly applied, the bentonite pond seal should last for years and years to come, UNLESS the soil at the bottom of the lake changes. For example, we have had cases where clients apply a bentonite blanket around the pond and then stock and deer walk around the area, removing the bentonite that was applied and therefore preventing a correct seal from being created. That’s why it is very important to consult with an expert on the best application method for your pond, they are familiar with many farm pond variables and considerations and will be able to advise the best application method to obtain the desired results.

I have had a bad experience with bentonite before, have you helped any clients in my situation?

Bentonite is cost-effective, but we can’t emphasize enough the expertise required to apply the bentonite to make sure it creates a long-lasting and efficient seal. At Lonestar, we have people that have worked in the field for many years and have developed their expertise from working with the people at ranches and farms. On top of that, at our facilities, we are able to provide different grain sizes, which also affects the rate of success for sealing your farm pond. We have had clients that have applied bentonite before unsuccessfully, called us and then have had their ponds full for many years without leaks.

If you need a quote, please give us a call. (210)378-2008

To know more about how to fix a leaking pond application methods visit our Bentonite Pond Sealant page.

Why Bentonite? Discover why Lonestar Bentonite Pond Sealer is the best solution

Do you need extra help fixing your pond? We provide de full service, to know more about this service please visit or Fix ponds and lakes page.

Planning to build a new pond? Let us do the heavy lift! Lonestar Minerals have the expertise and the equipment to Design and construct ponds and lakes.

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