The Best Koi Pond Liner Materials, And The Worst

A koi pond with water lilies and a small waterfall in the background.

Choosing a suitable pond liner material is one of the most critical decisions if you’re planning to build a backyard koi pond. While there’s a lot of information available about koi fish prices, the types and costs of koi pond liners aren’t discussed as much. The pond liner material you choose will determine how long your pond lasts, how easy it is to maintain, and how much money you’ll ultimately spend.

To help you make an informed decision, we’ve put together this guide to the best and worst koi pond liners on the market.

8 Koi Pond Liner Materials Ranked

1. EPDM Pond Liner (ethylene propylene diene monomer)

EPDM pond liner is a type of synthetic rubber that is often used for lining ponds and other water features.

Pros 

-Strong and can withstand a great deal of weight. This strength means they can support larger fish’s weight, such as koi, without sagging or stretching. Their toughness also makes them pretty puncture resistant

-Very resistant to sunlight, meaning they won’t degrade over time when exposed to UV rays. This resistance to UV damage makes them a good choice for ponds that sit in sunny areas

-Their black color helps to create a natural-looking pond by absorbing sunlight and creating a darker environment for aquatic plants to grow

-It’s easy to install, even for DIY enthusiasts who have never installed pond liners before

-High flexibility helps them stretch, and they can easily manage curves and corners

-Can last 27 years and more with proper installation and care

-Temperature resistance helps EDPM koi pond liners keep their grip on rough surfaces, and they won’t crack in cold temperatures

-They’re nontoxic to fish, plants, and other flora and fauna

Cons 

-One of the main disadvantages of EPDM pond liners is the price. It is one of the more expensive types of pond liner on the market, so it may not be affordable for everyone

-Another downside to this pond liner is its thickness. It’s pretty heavy, making shipping difficult, and may raise shipping costs. You’ll want to try and find it locally so you can pick it up to save money

-Since EPDM liners are black, they can make it more difficult to see fish in koi ponds

*We cover liners with rocks and gravel to protect them better and make your pond look more natural and beautiful 

2. RPE (reinforced polyethylene)

Premier Pond employees installing a pond liner.

RPE is a type of synthetic rubber reinforced with a woven fabric backing. RPE is made by combining two or more layers of material, with the reinforcement layer typically being a fabric such as polyester or fiberglass.

Pros

-RPE also has good resistance to UV rays, making it ideal for use in outdoor applications

-One of the biggest advantages of RPE is its price. It is typically less expensive than EPDM or PVC pond liner, making it a budget-friendly option for many homeowners

-It’s a lightweight material. This flexible liner makes installation much easier than pond liners made of heavier materials like concrete. In fact, many homeowners opt to install their RPE liner themselves, which can save you a considerable amount of money on pond building costs

Cons 

-RPE is not UV-resistant. This lack of UV-resistance means that over time, exposure to sunlight can cause the material to degrade and become less effective at doing its job

-It’s not completely impervious to root penetration. While the material can resist tearing and punctures, roots can sometimes find their way through small holes or cracks in the liner. However, this isn’t usually a major problem as long as you regularly inspect your liner for any signs of damage. It also isn’t as puncture resistant as EPDM

-Since it’s a newer material, there isn’t much research on how long it lasts. Right now, most warranties go up to 20 years, but much of the lifespan depends on how exposed the liner is to sun and weather

3. FPP (flexible polypropylene)

Flexible polypropylene (FPP) is a type of synthetic plastic that is often used to line ponds and other water features. FPP pond liners are made from polypropylene resin and other materials.

Pros

-High flexibility. This flexible liner has a much lower modulus of elasticity than EPDM rubber, which means it can stretch up to twice its original length without breaking

-This flexible liner is very easy to install, even if you don’t have a lot of experience with backyard pond projects

-The material is also lightweight, so it’s easy to handle and ship

-FPP pond liner is relatively affordable compared to other materials like concrete or rubber

-This flexible liner is ideal for ponds with custom shaping

-Can last up to 30 years

Cons

-One of the biggest problems with this type of liner is that it’s more prone to leaks than other materials. If your liner develops a leak, you’ll need to replace the entire thing—which can be costly

-Since the material is flexible, it’s more likely to develop wrinkles or folds, which can also lead to leaks

-Although the FPP pond liner is less expensive than other options, it’s also not as durable. The material isn’t as resistant to oxidative damage or chemicals so it may degrade more quickly

4. Butyl

A black butyl koi pond liner sits on the edge of a pond.

Butyl is a type of synthetic rubber that’s usually made from a blend of synthetic polymers.

Pros

-Butyl pond liner is very affordable compared to other types of liner

-It’s durable when it comes to withstanding UV rays, extreme temperatures, and ozone

-It’s easy to install due to its flexibility

-Black butyl pond liner better blends in with the surrounding rocks and plant life to create a more natural look 

Cons

-Tends to be on the higher side when it comes to price

-Butyl pond liner can also be challenging to repair if it becomes damaged

-Not durable when it comes to tears and punctures

-Some people also find the black color of butyl pond liner to be unappealing

5. LLDPE (low-density polyethylene)

LLDPE is a synthetic rubber similar to HDPE in terms of durability and flexibility.

Pros

-LLDPE is durable and UV-resistant (though not as resistant as HDPE liners.) This UV resistance makes it a good choice for building ponds in sunny areas

-It’s also flexible and conforms to rough terrain more easily than an HDPE liner

-LLDPE is relatively inexpensive, making it a good choice for budget-minded homeowners

-It’s easy to find LLDPE liner in a variety of sizes, so you can find one that fits your pond size perfectly

-This liner material can last up to 36 years when used as recommended

Cons

-LLDPE isn’t as thick as other types of pond liner, so it may not be as durable in the long run

-It’s also not as puncture-resistant as other materials, so be careful when handling it

-Some people find the black color of LLDPE liner to be unappealing. If this is a concern for you, look for white or green Pond Armor coatings, which can help improve the appearance of your pond

-It can tear length-wise more quickly than other pond liner materials

6. HDPE (high-density polyethylene)

HDPE is a synthetic rubber that’s known for its strength and flexibility.

Pros

-HDPE liners are UV rays and chemical resistant, as well as durable in general (except when it comes to punctures) 

-They are also flexible, making them easier to install than other liners. 

-HDPE liners are less likely to leak than other types of liners. 

Cons

HDPE liners can be expensive

-They aren’t very puncture resistant

-Low flexibility, which makes installation more difficult

-It’s a heavier material, which makes it expensive to ship and harder to install

7. Preformed Pond Liner

Preformed pond liners are made from molded fiberglass or plastic.

Pros

-Easy to install – One of the most significant benefits of a preformed pond liner is that it’s easy to install. Unlike flex liners, which can be a real challenge to work with, preformed liners simply need to be placed in the hole you’ve dug and filled with water. This makes preformed liners a great option for do-it-yourselfers who want to save money on installation costs

-Affordable – Another advantage of these pond liners is that they’re pretty affordable. They’re often one of the most cost-effective options on the market. This makes preformed liners an excellent choice for budget-conscious shoppers who still want a high-quality pond liner

-Low maintenance. Preformed pond liners are also low maintenance. Flex liner ponds can develop leaks over time, which can be expensive and time-consuming to repair. But preformed liners are much more durable and less likely to spring a leak. This durability means you’ll save money on repairs over the life of your pond

-Variety of shapes and sizes. Preformed pond liners come in various shapes and sizes, so it’s easy to find one that will fit your specific needs. Whether you want a small pond for your patio or a large one for your backyard, there’s sure to be a preformed liner that’s perfect for you

Cons

-Limited flexibility in terms of shape and size. If you have specific requirements for your pond, such as an odd size or shape, you may need to go with a different type of liner 

-They aren’t as durable as concrete or flex liner. While preformed liners are relatively durable, they’re not as tough as concrete or flex liner ponds. So they may need to be replaced more often if you live in an area with severe weather conditions or if your pond is subject to high levels of use. Overall though, preformed liners usually need the least amount of maintenance.

8. PVC (polyvinyl chloride)

PVC pond liner is a synthetic material made of polyvinyl chloride or PVC

Pros 

-Affordability: PVC liner is one of the more affordable options on the market

-Flexibility: PVC is a very flexible material, which makes it easy to work with when constructing your pond

-Durability: PVC is a very durable material that will last for many years with proper care

Cons

-Leaching: over time, chemicals in PVC pond liners can leach into the water of your pond, which can be harmful to your fish and plants

-Installation Difficulty: since PVC is a flexible material, it can be difficult to install without wrinkles or creases, which can lead to leaks

-Low UV, ozone, and weathering resistance

Make Your Koi Pond Installation A Breeze By Using Premier Pond’s Pond Installation Service

A pond with plants growing out of the water and koi fish visible beneath the surface of the water.

If you have been considering a koi pond for your backyard, now is the time to take the plunge! They are beautiful and relaxing to look at, and koi ponds provide many benefits for homeowners.

But not everyone has the energy, time, or help to install a koi pond on their own. If that’s the case, you can rely on Premier Ponds to help you get your pond oasis.

Fill out our contact form today, and let us help you get started on building your very own backyard oasis!

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