Choosing The Best Pond Liner For Your New Pond

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At first glance, all pond liners really do look alike! They all seem to be made of synthetic black material that looks identical across brands. You might be surprised to learn that each brand has several differences in construction and chemistry that will have long-lasting consequences for your future pond. 

That’s why I’ve curated this list of the best pond liners for that next big pond project. There’s something here for every budget and pondscape, so let’s dive into what makes these liners so great!

The Best Pond Liners of 2021

There are hundreds of pond liners on the market today. But the five I’ve found offer options for nearly everyone regardless of the type of pond:

• HALF OFF PONDS – 20-Mil LLDPE Pond Liner
• Aquascape PRO Grade EPDM Boxed 45 Mil Liner **Top Choice**
• UWIOFF 20 Mil Pond Skins Pond Liner
• MacCourt Pond 125-Gallon Kidney Shaped Chesapeake Pond
• HALF OFF PONDS Savio Select 2000 Pond Kit

My Top Choices for the Best Pond Liners

Let’s take a look at each of these in-depth to help you find the best one for your application. If all the talk about 20-mil, 30-mil, LLDPE, and EPDM confuses you jump to the bottom where I break all of the technical mumbo jumbo down.

HALF OFF PONDS 20-Mil LLDPE Pond Liner

HALF OFF PONDS offers a number of pond liner options and one of my favorites is their 20-mil Pond Liner. Here we see a new acronym: LLDPE, which stands for “linear low-density polyethylene.” LLDPE is the lighter form of HDPE (high-density polyethylene) and has similar qualities as a result. Since the material is thinner, it’s frequently used for home-sized ponds and as capping material for landfills. 

Being lower density, LLDPE is lighter and more flexible than HDPE while remaining just as chemical and UV resistant. It’s still not as flexible as EPDM rubber but it’s significantly more durable and resistant to both tears and punctures. This makes it an ideal option for pond beds that have too many rocks and other hazards to easily remove. LLDPE is also unaffected by the seasons, neither expanding nor shrinking in response to temperature changes.

The slight lack of flexibility makes it better for designs where you have curves to work with. Abrupt turns don’t work so well unless you cut the liner, which can be challenging. HALF OFF PONDS is so confident in the UV resistance of this material that they offer a 10-year Standard Manufacturer’s warranty if the material has continual UV exposure. And assuming it’s protected from sunlight, you can expect a 40-year lifespan! 

Aquascape Pro Grade EPDM 45 Mil Rubber Liner

If you’re unsure about the benefits of LLDPE and wary of PVC liners then the Aquascape EPDM 45 Mil Rubber Liner might be a good choice for you. One advantage this Aquascape design offers is its 45 mil thickness. 45 mil pond liners are on the thicker side (just over 1 mm in thickness). 

Anything over 30 mil is ideal where foot traffic on the liner may occur and also provides extra protection against tree roots from penetrating the liner. This 45 mil liner is 50% tougher and better for pondscapers with rocky ground as well as tree roots. And being EPDM rubber it remains flexible and supple compared to the HALF OFF PONDS LLDPE liner. The Aquascape Rubber Liner can be placed easily into the pond bed and made to lie flat and follow curves in the landscape with no fuss. 

Just keep in mind that a liner this thick is going to be heavier and more difficult to install. EPDM is also somewhat pricier than other materials – but only because it’s such an ideal pond liner material. In fact, Aquascape offers a 20-year guarantee on their EPDM liner! Still, a 30 or 20 Mil liner might be better if you don’t need this much puncture resistance and want a more affordable product.

UWIOFF HDPE Pond Liner, 20 Mil

The UWIOFF HDPE Pond Liner is an excellent choice for small to medium-sized installations. This pond liner is available in 10′ x 13′ and 7′ x 10′ sizes which are quick to install and long-lasting! HDPE is the strongest material you can use for a pond liner. It’s durable enough to resist punctures from rocks and roots from below as well as foot traffic and pet claws from above.

The durability of HDPE is also a drawback since it’s quite stiff, even more so than the HALF OFF PONDS LLDPE liner. I wouldn’t want to use this for a large pond project where I had to follow curves in the landscape. But the UWIOFF HDPE liners only come in a maximum of 10′ x 13′ which works for ponds up to 500 gallons of water. So if you need something larger you will need to look elsewhere.

If the area you’re placing this pond liner in is going to get constant sun, and thus UV, exposure, you can’t ask for a better material than HDPE. This liner is also tough enough for you to forgo adding pond liner underlayment if you wish. Just keep in mind when aqua scaping that this liner is shiny rather than matte in color. It tends to reflect light and isn’t as traditionally pleasing in tone as an HDPE rubber liner.

MacCourt Pond 125-Gallon Kidney Shaped Chesapeake Pond

Unlike the other liners listed here, the MacCourt Pond is a kidney-shaped molded pond. This liner is for someone who wants something small and simple. The hard synthetic material used by this molded pond is even more puncture and stress-resistant than the most durable of flexible pond liners.

The UV stabilized material ensures you will get years of life out of this pond, though unlike most of the other brands, MacCourt doesn’t back this with a guarantee. Hard molded ponds are also by far the easiest to clean since even hard-bristled brushes and scraping won’t cause them any damage.

Since it holds a fixed shape, it will look its best even if you dig an imperfectly shaped hole. Just make sure that enough support is provided along the sides to prevent it from warping. Some molded ponds are thick enough to sit above ground, giving you extra landscaping possibilities. 

Unfortunately, the MacCourt is neither thick enough nor molded properly for above-ground installations; it must be dug into the earth. On the plus side, if you prefer molded ponds MacCourt makes several designs alongside their Kidney Shaped Chesapeake, including a 275 gallon St. Croix design!

HALF OFF PONDS Savio Select 2000 Pond Kit with EPDM Rubber Liner

The Savio Select 200 Pond Kit is for those of you who want all of the necessary pond accessories in one kit. Their EPDM LifeGuard15′ x 20′ liner will hold up to 1,900 gallons of water. If you want something smaller they have 3 additional kits going all the way down to a 10′ x 10′ which holds up to 400 gallons.  These are not as large as their LLDPE options nor Aquascape’s EPDM liner.

Being a complete pond kit, the Savio Select includes a bronze 1-watt spotlight for highlighting statues, plants, and other pondside decorations. You also get flexible, kink-free tubing for pond filters, a 2,000 gallon per hour pump, a filter, black foam for sealing the liner and installing water features, and even a bottle of beneficial bacteria to jump-start your cycling process!

Also included is underlayment, which helps protect the 45 Mil rubber even further. It’s worth mentioning that in order for the lifetime warranty to remain intact, you do have to install the underlayment.

You also have the option of buying an even nicer package that includes the liner, the above accessories, and their 18-Watt Uvinex System. UV clarifiers are great for killing green water algae, which are a common problem in household ponds that have high nutrient loads and are exposed to abundant sunshine.

Which is the Overall Best Pond Liner?

Each of these pond liners has something to offer the discriminating landscaper looking to start a new project. But the option that meets the needs of the majority of pondscapers is the Aquascape EPDM 45 Mil rubber liners. They use the material that’s the easiest to work with when it comes to molding your liner to fit your design. And the 45 Mil thickness negates the weaknesses of EPDM relative to other materials.

We get an assortment of sizes as well, from as small as 8′ x 10′ to as large as 20′ x 25′. And Aquascape is confident enough in the durability of their liners to back it with a 20-year manufacturer’s warranty, free of conditions imposed by other manufacturers like HALF OFF PONDS.

Why is a Pond Liner Important?

Of all the materials you’ll use to build your pond the liner is arguably the most important. Because without some sort of liner, the chances are high that you will slowly lose water over time. Earth ponds are a popular concept but it takes a clay-rich soil to keep your pond water in place. Unless you’re lucky enough to be living in such a region already, you’ll need to install an artificial liner if you want a pond.

Pond liners also make maintenance significantly easier since you aren’t having to deal with the muck that blends into the soil layer of a natural pond. Instead, you can use a pond vacuum or other device to remove any free-floating debris, exposing the durable surface of your pond liner. And when performing a spring cleaning, you can drain the pond, expose the liner, and scrub it free of algae and biofilm with ease!

Lastly, a pond liner is an aesthetic choice as much as a functional one. As we’ll see below, a good pond liner has the ability to conform to the shape of your pond or provides a rigid form that’s unchanging yet durable!

How Do I Choose the Best Pond Liner?

Flat versus Preformed Pond Liners

The first question you’ll likely have when shopping for a pond liner is whether to go for a flat or a preformed (molded) pond liner. The truth is that there is no one answer as to which is better; both flat and preformed pond liners have something to offer every potential pond keeper! 

Preformed pond liners offer you the option of a faster installation process. Preformed pond liners use hard plastic or fiberglass walls that you can dig a hole to fit in place or let sit on the surface of your lawn as an above-ground pond. This extra rigidity and durability means they can take more abuse in the form of rocks and roots pushing into it from below as well as heavy rocks inside the pond. Even if rocks slide and get shifted about, at worst, they will merely scratch a preformed pond liner. 

The downside of a preformed pond liner is that you’re stuck with whatever shape you end up purchasing. You simply don’t have the customization that a flat liner affords you. If you choose not to bury your preformed pond liner you also don’t have the insulating capacity that the ground offers, which moderates both the winter’s chill and the summer heat for your fish. 

Flat pond liners have all of the advantages preformed pond liners don’t, and vice versa. A flat pond liner can be installed to fit nearly any pond design you have in mind. The material they use ranges from stiff but flexible to entirely soft and supple. These qualities make them gentle on the skin of both you and the fish when working around the bottom of a pond.

And since they are dug into the ground they have some insulation from extreme cold and heat once winter and summer arrive. Preformed ponds also tend to come in specific sizes. And rarely do they come in sizes beyond a few hundred gallons. A flat pond liner can be installed to create ponds as small or as large as your design requires!

Flat pond liners are also easily customized and can be added on to. Few pond keepers are satisfied for a lifetime with an initial installation. Eventually, you’ll want to deepen it, add waterfalls, streams, a second pool, or who knows what else! Flat pond liners are perfect for future improvements!  

PVC vs EPDM vs HDPE for Flat Pond Liners

When shopping for a flat pond liner you’ll have to get acquainted with several acronyms that clue you into what each liner is made of. The most common are PVC (polyvinyl chloride), EPDM (ethylene propylene diene monomer) rubber, and HDPE (high-density polyethylene). 

Of the three, PVC is the one that’s the least suitable for flat pond liners. You’re likely already familiar with PVC when used for pipes and tubing. PVC liners do have the advantage of being extremely inexpensive and can be folded repeatedly with no risk of stress fractures forming over time.

But making PVC flexible enough to be used for a liner requires chemicals that are not at all fish safe. These chemicals can easily leach out into your pond water if you’re using PVC as a primary liner (it does make a great backup liner to protect your main liner and slow or prevent leaks). 

PVC also gets weakened by temperature lows and highs. The last thing you want is for your PVC liner to get rigid and start to crack during an especially cold winter day. It’s also weak in general to UV and ozone exposure, which are common outdoors. On the plus side, you can use heat to “weld” seams of PVC together, making it ideal for quick pond installations.

EDPM rubber is one of the two materials more commonly seen in pond liners. This synthetic rubber material is naturally stretchy and has a soft quality that’s pleasant to the touch. It’s also not very thermally expansive, meaning temperature extremes won’t cause it to lose contact with the walls of your pond or crack in the cold. 

It’s a little pricier than PVC liners but considering it’s entirely fish safe and doesn’t leach harmful agents into the water, EDPM is well worth the cost. The only real downside is that you can’t use heat to melt the edges together when designing a pond with an EDPM liner because heat does degrade the material, weakening it enough that leaks could form in the future. You have to use tape to join any seams in the material.

Lastly, we have HDPE, which is an even stronger synthetic material that’s designed exclusively for large pond projects. HDPE is also very UV and chemical resistant as well as cheaper than EDPM rubber. HDPE pond liners can last nearly 40 years once installed and can be heat treated to join the seams together during installation.

While HDPE is also entirely fish-safe, its stiffness makes it unsuitable for certain pond shapes. It’s also sensitive to punctures, such as with rocks missed when digging out a hole for the pond. Small stress fractures can easily form if you aren’t careful in removing rocks. But roots can also penetrate it more easily with enough time. 

Concrete Pond Liner

While it may not seem obvious at first, concrete is also an excellent material to line a pond with. It’s extremely strong and long-lasting and completely impervious to water. Assuming you get the pond design right at the beginning, you’ll have decades to enjoy the fruits of your labor. But that longevity can also be a curse since altering the shape of a concrete pond is much more difficult than a flat pond liner.

Concrete pond liners do tend to slowly leach chemicals into the water for a few years. The lime content tends to raise the pH for a long time. While it’s not especially toxic to most fish (goldfish and koi both thrive in alkaline conditions) it’s something you’ll have to monitor and potentially counter with pH decreasing agents.

Concrete pond liners also cost much more to install and offer a rather rough surface to work with. It’s potentially abrasive, which can cause damage to the soft barbels of koi. But it’s also leak-free compared to any flat pond liner and very easy to keep clean! 

What About Pond Liner Underlayment?

Pond liner underlayment is a soft, fibrous material that gets laid down as a mat in between the ground and your flat pond liner. Underlayment looks baffling at first since it’s clearly not waterproof and isn’t rigid, either. So what’s the point of this material?

Pond liner underlayment acts as a softening barrier against rocks, roots, and other natural hazards to your actual pond liner. The tips of rocks may not look like a problem at first. But the weight of all that water pressing down on a liner, the actions of fish, and other movements can cause a rock to wear through a bare pond liner over time. The underlayment acts as a barrier, softening the contact of hard and sharp surfaces with the main pond liner!

I always recommend pond liner underlayment even if your soil appears to be clear. The pressure of a pond weighing down over the years can cause it to come in contact with hidden sharp objects near the surface. And the roots of trees and shrubs are always a concern because they can penetrate a liner over time, causing leaks to arise. The underlayment helps deflect incoming roots and protects the liner, extending its lifespan.

Final Thoughts On Pond Liners

Shopping for your pond liner may not be exciting but it’s one of the most important decisions you’ll ever make involving your pond. The right liner can make or break a pond before you even get to add fish or plants to it! Hopefully, the materials here allow you to make an informed decision that will give you many years of happiness as your pond flourishes before your eyes!