Q: I built a home a few years ago and in the process we needed a large amount of fill dirt. Under the recommendation of my builder we decided to dig a pond for the fill dirt. I was told by my excavator that it would take several months for my pond to fill. It is now 3-years later and I have no water! Over the last several years I have tried lining my pond with blue clay and bentonite with no success. I know you sell liners. Will they work for a ½ acre pond? – Rick of Illinois
A: Yes. A pond liner is the only way you can guarantee to have a leak proof seal.
If you would like to explore the possibility of a liner, then you will need to gather a few pieces of information so we can best help you:
1) Existing Water – Many ponds retain some water. We do not recommend lining a pond that contains more than 25% of its fill capacity for any extended period of time. Unless you plan to put at least 2’ of soil on top of the liner or make provisions to drain the water from under the liner.
2) Measure Your Pond – This is best accomplished by using a flexible tape measure (available at Home Depot / Lowes). Stretch the measuring tape from water line to water line allowing the tape to contour to the pond’s bottom. In general, we recommend adding an additional 5′ to 10’ to this number to make up for the liner settling and the anchoring trench.
3) Give us a call 888-766-3520 or click here to visit our website for more information.
Filed under: Liner, Pond & Lake | Tagged: 20 mil PVC, liner, liner for pond, pond liner

I have not yet dug the earth for our pond. What if it does fill with natural water by 25% or greater as you mention in the above information. We live in an area surrounded by swamp.
Lisa, this is a good question and I should have elaborated on it a little more in the blog.
#1. If you pond fills to the top and stays that way, then you don’t have to worry about a liner at all, nor is using a liner at this point a possibility.
#2. When you have 25% or more of the pond’s capacity filled with water, it can be very difficult to line the pond. If you place the liner on top of the water and fill up the pond, organics are continuously decaying underneath the liner. As these organics decay, they create gases. As these gases collect, they can literally lift the liner to the surface. It will look like liner bubbles on the surface. This is why we do not suggest using a liner when the pond will hold more than 25% of its capacity on its own.
We usually suggest researching bentonite or lining the sides with clay when your pond will only contain 25% or greater, as these may be the only options to allow the pond to fill with water.
I have used check valve bulkheads when laying the liner to help release the gases underneath the liner, but they don’t work that well on their own and usually require someone to manually release the gases.
Hopefully this helps!
The Pond Guy
OK but what if the natural water level is seasonal? It will dry up over the winter if I turn the pump off. And what is the natural water table rises? Wouldn’t the greater weight of the water on top of the liner offset the rising pressure.
So if you get these gas bubbles what happens if you just poke a small hole in the liner to release it? I have a big pump and well capable of filing the pond in 30 days (4 Ac.) but with the sandy soil I can only maintain a depth of about 3′ then it will drain latterally though the ground. I have been considering a liner after I complete the eradication of the cattails and use muck away pellets to eat up the organic matter.
James,
If this does happen and you were to get bubbled liner, there are air pressure valves that you can purchase to release the gas. Basically it is a bulkhead fitting with a spring valve that will open up when the pressure is too much.
In your case it sounds like you shouldn’t have a problem with a liner, especially if you have sandy soil. A liner will work wonderfully in that situation.
can you elaborate a bit more on the pressure valves and how they get installed?