Custom Fish Pond Liners: A Complete Guide

pond liner

What Is the Purpose of a Pond Liner?

Pond liners prevent water from entering the soil. They act as a barrier between the water and the soil, preventing water loss.

A pond liner, on the other hand, only works if it is free of leaks. In practice, leaks can occur for three reasons:


  1. Fabric abrasions or tears.
  2. Leaks in the liner fabric’s seams.
  3. Liner fabric age and deterioration.


Tears and Puncture

Small rocks, tree roots, and other objects may remain in the hole excavated for the pond. These may not be obvious, but once the liner is installed and your pond is filled, the weight of the water pressing down on the liner material may be enough to puncture it. You want a good, strong liner material to avoid that risk.


Seams that are leaking

Your pond liner will most likely be constructed from multiple sheets of liner material that have been welded together. Leaks can occur anywhere a seam connects two sheets. The main issue is whether the welding is done in the factory or on-site during installation.


To avoid seam leakage, factory-welded, custom pond liners are the best option. Advanced technology can be used in factory welding to produce more consistent welds. Welding is also carried out under controlled conditions. Welds made in the field during installation, on the other hand, must contend with uneven ground, weather, less sophisticated welding equipment, and other factors that result in less-than-perfect welds.


Another critical consideration for fish ponds is whether or not the pond will have a dock. If this is the case, the dock columns will penetrate your liner, creating another point where leaks can occur. In this case, you’ll need to use a custom liner with dock-specific column boots.


UV rays and weather

To avoid leaks, your pond liner must age properly. This means that the liner material must be UV and weather resistant. Liners are made of synthetic materials with long chain molecules. UV rays can eventually break down these long chain molecules, causing the material to become brittle and crack.


To avoid this, choose a liner made of a material that is either naturally UV resistant or has a protective coating.


Selecting the Best Pond Liner Material

pond liners

Choosing the best pond liner can be difficult because the best option is dependent on your specific needs and environment.


Your vendor should ideally provide liners in a variety of materials. If you ask a vendor who only sells EPDM liners, they will likely tell you that EPDM is a great choice for any pond.


The most important characteristics of a fish pond liner are:


  • Adaptability
  • Stretching resistance and strength • Puncture resistance
  • Lightweight (for portability) • UV resistance
  • It is non-toxic!
  • Long life expectancy



We make liners out of over a dozen different materials. In our 30 years of experience, we’ve discovered that two liner materials work best for fish ponds: reinforced polypropylene (RPP) and reinforced polyethylene (RPE).


RPP is best suited to smaller ponds. It has a coating that is highly resistant to UV and weathering and is one of the longest-lasting liner materials available.


RPE is best suited to larger fish ponds. It’s an excellent, low-cost material that’s highly resistant to punctures and has the highest UV ray resistance.


Whatever material you choose, make sure you understand the manufacturer’s warranty for the liner.


How much lining do you require?

You’ll need to know how large a pond liner you’ll need to estimate the cost of your pond. There are numerous liner calculators available on the internet. Here is a pond liner calculator.


These calculators are useful if you have a pond that is round or oval in shape. If you have an irregularly shaped pond, such as a bend or a kidney shape, please ask our staff to prepare a more accurate estimate of the size you require.


Keep in mind that your pond liner must be slightly larger than your pond. You’ll need an extra 5 feet around the pond’s rim to secure the liner in a trench. Make certain that the calculator you use takes this into account.

How Difficult Is Pond Liner Installation?

If your liner is made in a single piece, you can install it yourself as long as you follow proper installation procedures. You can review our comprehensive guide to installing pond liners.

Also Read: The Importance of curb & Paver Machine in Road Construction

A welder with experience installing pond liners is required to install a multi-piece pond liner.


Check with the manufacturer before ordering your liner to ensure that it will be wrapped in a protective layer of felt. You don’t want it to get damaged in transit.


When the liner arrives, make sure to thoroughly inspect it before signing for it.


Unroll the liner and secure it in your pond. To secure the liner, dig a narrow trench around your pond, tuck the liner’s edges into it, and then fill it to keep the liner in place. The size of the trench required is determined by the size and slope of your pond. More information on this and other tips can be found in our installation guide.


Do you still have questions? Not sure which material to use for your liner? We are happy to answer any questions you may have.