A pond liner is a critical part of your pond setup. Although most people assume a pond liner’s sole responsibility is to keep water in your pond and out of the surrounding ground, this is an incorrect assumption. Pond liners are also responsible for providing a base for plants to root themselves in and fish to explore. With so much responsibility, it is important to choose the best pond liner for your situation.
In this article, we’ll explore everything you need to consider when choosing the best pond liner for your pond, including different types of liners. We will also review some of our favorite best pond liners and share their optimal use cases.
Recommended Pond Liners:
What is the best pond liner?
Our recommended option is Firestone EPDM Rubber Pond Liner, 10-Foot Length x 15-Foot Width x 0.045-Inch Thick. We like this liner because it is quite durable and able to withstand extreme cold and direct UV light. Additionally, the liner can be stretched around corners to fit nearly any pond design, making it a great choice for custom ponds. It is an EPDM liner.
What is the purpose of a pond liner?
A pond liner’s primary function is to keep water from leaking out of your pond. Skip the pond liner and you’ll eventually have issues with low water levels. The only exception here would be extremely clay-rich soil; if you’re starting a pond in clay-rich soil, your pond might retain water. But we would still suggest lining it just to be safe as clay is still water permeable.
If you skipped the pond liner, plan to spend time refilling your pond every few days. This is not ideal from a time perspective, but even more importantly, from a water conditions perspective. You will have to pay extra attention to the water parameters with the constant influx of new water.
Additionally, pond liners help keep your pond cleaner. They keep all of the natural dirt out of your pond. If you want a super clean pond, invest in a good pond liner and a good pond vacuum. Further, pond liners can serve as substrates for plants to anchor onto, or as a base onto which you can layer additional substrate. They give you extra flexibility with your pond setup.
Do you have to line a pond?
We recommend it. It will make your life easier long-term. However, you don’t technically have to line a pond. Very shallow ponds (less than 1-2 feet) experience less pressure from the water so they might not require a dedicated liner. However, they will still require dense silt soil that is well compacted. Overall, it is easier to not guess the liner requirement and just do it.
How to Pick a Pond Liner
When choosing a liner for your pond, there are a lot of options in style, material, and design.
Below, we explore some of the main factors that differentiate pond liners and make some styles of liners better for certain ponds.
Flexible vs. Preformed vs. Concrete Floor
This is pretty straightforward. Do you want a flexible liner? A preformed liner? Or do you want to start with a concrete floor for your pond? Each option has advantages and disadvantages.
Flexible liners are essentially a piece of liner material that can be custom cut to fit your pond’s dimensions.
Flexible liner’s advantages are:
- Simple to use
- Least expensive types of pond liners.
- Most adaptable for unusually shaped ponds or landscapes where you want the pond to seamlessly integrate
- Easily modifiable for future pond changes
Flexible liner’s disadvantages are:
- Requires most work upfront in measuring and cutting correctly. Mistakes mean you might need to start over.
- Needs to be replaced every few years
Preformed liners are made of hardened plastic or rubber. The shape they come in is the shape they will retain, so what you see is what you get in terms of your pond shape.
Advantages of preformed liners:
- Simplest option with minimal work upfront. Simply dig the hole and back-fill around the gaps.
- Relatively inexpensive compared to concrete floors
- Good choice for first-time pond owners
Disadvantages of preformed liners
- More expensive per square foot than flexible liners
- Limited to the shapes for sale. If you want something unusual or creative, preformed liners are not the way to go
- Needs to be replaced every few years
Concrete liners are the best choice for a pond liner that will last for decades. Advantages of concrete floors include:
- Ability to match a custom design
Disadvantages of concrete floors include:
- Expensive. Pouring concrete is time-consuming and difficult to get right, especially for a non-expert. Hiring an expert is an option but will add cost to your pond.
Weather Conditions around the Pond
The weather conditions around your pond can influence the best type of pond liner for you. This is because some liner materials can withstand almost all temperatures and conditions but other materials will crack or wear down over time if exposed to extremes. The two main factors you need to consider are cold temperatures and direct, consistent sunlight.
The first weather element to consider is your winter temperatures. If freezing temperatures are common in your area, you’ll need a pond liner that won’t freeze and crack. In cold weather extremes, we recommend EPDM and HDPE liners, which are both able to withstand negative temperatures. Avoid PVC and butyl rubber. You could also think about adding a pond heater to the mix to help with this situation.
Also, consider how sunny the area where the pond is located is. Exposure to UV light can break down the chemicals in PVC or butyl rubber over time, resulting in unwanted cracks. EPDM, HDPE, and fiberglass liners are more resistant to UV light but will also wear down over time. If you need a UV-proof option, concrete is is your only real option.
Pond design and aesthetics are personal decisions. Your pond liner choices may be driven by the look you’re trying to achieve with your pond.
The first consideration is your pond structure – above or below ground. If your pond is above ground, you’re likely going to need to select a preformed fiberglass pond liner. This is the only material that can maintain its shape over time.
Second, think about the aesthetics of the bottom of your pond. Will you be able to see the bottom when peering in? If the bottom will be visible, you’ll likely want to select a more natural-looking bottom that contours closely to the ground. HDPE liners can be a good option here; EPDM or butyl rubber liners will often look clunky and not closely map to the bottom of the pond.
Lastly, consider if you might want to expand your pond in the future.
EPDM and PVC liners can be easily expanded with liner tape. HDPE and butyl rubber liners must be welded together. Concrete is the most difficult to bond together.
Complexity of Pond Design
Your pond design is a major factor in determining the best pond liner.
If you have a complex pond shape, EPDM and HDPE liners are probably your best choice. They both stretch slightly which is important in tight corners. These materials are also sold in large sheets so you can more easily use a single sheet versus needing to weld together separate sheets for a smooth design.
Butyl rubber is not a great choice for complex ponds. It is relatively inflexible, which means it will be difficult to have it map perfectly to your design. It is also sold in limited sizes because of manufacturing limitations which means you’re more likely to need to weld together multiple sheets.
Concrete flooring can be used for almost all designs. However, complexity in pond design requires advanced concrete skills so expect to hire a professional if you’re using concrete on a difficult design.
Size of Pond Liner
For flexible pond liners, you need to calculate how much liner material you’ll need for your design.
To calculate your required materials:
- Find the widest, longest, and deepest points of your pond design, measured in feet.
- Double the depth of the pond and add one foot to that number.
To get the appropriate sheet size, take this number, add the length of your pond. Then start again with your first number and add the width of your pond.
For example, if you have a pond that is 5 feet deep by 10 feet long by 15 feet wide:
- (5 feet deep x 2) + 1 = 11 feet
- 11 feet + 10 feet long = 21 feet
- 11 feet + 15 feet wide = 26 feet
In this example, you need a sheet of liner that is 21 feet long by 26 feet wide to cover your pond.
Remember the Underlayment!
Underlayments are important! The function of an underlayment is to provide a physical protective barrier between the ground and liner. DIY suggestions include sand, old carpet, or newspaper.
However, we recommend a non-woven geotextile fabric. Non-woven underlayment is tough and won’t degrade the same way that old carpets and newspapers will. It also limits root penetration from nearby plants.
Budget can also be a major factor in the decision-making process. Flexible liners are the cheapest option for customized pond designs and concrete floors are the most expensive. Preformed pond liners are typically the middle ground price-wise but they provide a lot less design flexibility.
Advantages & Disadvantages of Different Pond Liner Materials
Understanding the advantages and disadvantages of different materials is an important part of choosing the right liner for your pond. We break down your options below.
Ethylene propylene diene monomer (EPDM) is a common material used for flexible pond liners. It is inexpensive and effective, making it a very popular choice. It is also flexible, making it adaptable for tight corners and custom pond designs.
EPDM sheets can be taped together with liner tape, which can help you expand your liner size as needed. This also means less stress in the cutting process because you can simply expand the pond by simply adding another EPDM sheet as needed with tape, if you make any mistakes.
EPDM is relatively heavy in weight, which can make it a little unwieldy. It is also more easily punctured by plant roots than other liner types. If using an EPDM liner, we recommend using an underlay to reduce the risk of punctures.
Polyvinyl chloride (PVC) liners are the least expensive pond liner option. They’re lighter in weight than EPDM and slightly more puncture-resistant. Like EPDM, you can use liner tape to attach multiple liner sheets together.
All of these advantages make them seem like they’d be a clear favorite over EPDM. However, they have some major flaws which make them relatively rare for pond use. PVC pond liners often contain trace amounts of arsenic. This makes them toxic to fish, which is clearly a big problem.
Secondly, PVC is prone to cracking in colder weather and/or direct sunlight. This means any PVC liners will need to be covered with at least a foot of soil for protection.
High-density polyethylene (HDPE) liners are one of the best choices for flexible pond liners.
They’re more puncture-resistant than both EPDM or PVC liners. They also weigh significantly less, making them easier to ship and install. This means less grunting and difficulty when you’re trying to shape it to your pond.
Further adding to their prowess, HDPE liners can be welded together with a heat gun. Heat-welded joints are more stable than liner tape, which means your pond will be less likely to leak.
HDPE liners are so strong enough that they typically don’t require an underlay, further reducing costs.
Guessing what the downside is? Well, you get what you pay for, so expect to pay more for an HDPE liner than either EPDM or PVC liners.
Butyl rubber is used in both flexible and preformed liners. It is easily welded together by heat, making for secure joints between multiple sheets.
Butyl rubber liners are more puncture-resistant than EPDM liners. They’re also cheaper than HDPE liners.
The downsides of butyl rubber sheets are a lack of stretch, so plan on welding together additional sheets to fit custom pond shapes. Additionally, preformed rubber options tend to only come in basic shapes so if you’re looking for something fancy, this is not your best best.
Fiberglass puts us in the domain of preformed pond liners. Fiberglass is incredibly strong, which means you don’t need to support the edges with soil. You can literally fill a fiberglass liner with water and keep it above ground as a raised pond (but you will probably want to decorate the edges to make it more beautiful).
As you might expect, fiberglass is also incredibly durable, meaning it won’t leak or crack when exposed to low temperatures and direct sunlight. It can even flex in the event of your pond icing over in the winter without cracking so if you live in a cold area, fiberglass is a great option.
If you’re looking for a pond that will last your lifetime, concrete is the way to go.
It is the most durable liner material and won’t crack under nearly any weather conditions. Tree roots a problem? Not an issue for concrete. They’re not weaving their way into your pond.
Concrete is typically used to construct large, deep ponds. It is the most structurally sound option for large ponds.
However, concrete is not the liner of choice for your average pond because it’s far more expensive and difficult to pour properly. If you’re going with concrete, hire an expert.
Best Pond Liner Options
Firestone is an EPDM liner with a 25-year warranty. This is a decade longer than a lot of other liners on the market.
Because this is a an EPDM liner, this liner is quite durable and able to withstand extreme cold and direct UV light. Additionally, the liner can be stretched around corners to fit nearly any pond design, making it a great choice for custom ponds.
This liner is only 1.1 mm thick. The benefit of this thickness it that it is lighter and easier to work with. The downside to this thickness is that it is more prone to punctures. For this reason, we recommend using a sturdy underlay with this liner.
- EPDM material
- 1.1 mm thickness
- 25-year warranty
- Pre-cut and boxed
- Flexible designs
- Environment and fish-friendly
- Relatively expensive
- Relatively thin so more prone to punctures
Best Budget Choice: Beckett Corporation Flexible Pre-Cut PVC Liner – 8 Foot x 10 Foot
This PVC liner from Beckett is a great choice for inexperienced pond owners who are on a budget. The liner is inexpensive compared to HDPE or EPDM liners, making it a good option for those who need a liner but don’t have a significant budget.
This option is 0.5 mm thick. It has about half the width of most EPDM liners but thicker than HDPE liners.
This liner is only available 8-foot by 10-foot sheets so if you need more liner than this, you’re going to need to seal multiple sheets together with liner tape.
As discussed above, arsenic is a concern with PVC liners as it is toxic to fish. However, Beckett produces this sheeting with ponds specifically in mind so the company is focused on making sure the product is safe for fish.
Like most PVC liners, this product is prone to cracking if exposed to direct sunlight or below-freezing temperatures. Therefore, this option is best used in more moderate climates.
Beckett does not offer any warranty on this liner.
- 0.5 mm thick
- Non-toxic PVC option
- No warranty
- Prone to cracking in below-freezing temperatures and sustained direct sunlight
The TotalPond Pond Skins Liner is designed by engineers to weigh 30% less than the other PVC liners. Despite this weight reduction, this option is still as strong as other PVC options. This product is 14.5 mm thick and reinforced with a strong polyester weave placed between the layers of PVC for extra durability.
This option also contains a textured surface that promotes positive bacteria growth, which is important for cultivating a healthy pond environment. These PVC liners are also puncture-resistant and UV resistant. This ultimately ensures years of use.
This liner is 7 by 10 feet so if you need a larger size, you will need to seam together multiple liners. Additionally, we recommend using an underlayment with this liner, which will help reduce any root punctures or tears.
- 14.5 mil thickness
- Weighs 30% less than other PVC liners
- Lightweight, ultra-durable, and easy to handle
- Textured surface promotes beneficial microbial growth
- Requires underlayment to reduce risk of tears and rips
Aquascape pond liners are the industry leaders when it comes to reliability and quality. As a testament to this quality. Aquascape provides a 20-year guarantee.
This EPDM liner is 45 mil thick. This thickness provides extra durability while retaining its ability to easily stretch for custom ponds. This particular option demonstrates exceptional resistance to solar UV damage, ozone, and oxidation issues, making it a reliable, long-term option for your pond.
- 20-year guarantee
- 45 mil thick
- Excellent lay-flat characteristics
- Easy installation; no tools required
- Safe for fish and plants
- Heavy so can be awkward to initially move around
Pond liners are integral to water gardens, Koi ponds, and waterfalls. Therefore, it is important that you choose the right one! LifeGuard pond liners are compatible with a range of water feature projects, making them excellent options for your customized pond design.
This liner resists UV deterioration and contains no plasticizers which become brittle and cause cracks and splits. LifeGuard Pond Liner is virtually indestructible; it is unaffected by hydrocarbons, mildew, rot, and freeze-thaw cycles. This means you’re purchasing a quality liner that will do its job – keeping water in and tree roots out.
They are also certified fish safe by Guardian Systems. They can also be easily attached to skimmers and filtering waterfalls. If you need a larger size, they can be easily seamed together.
- 45 mil thickness
- 25-Year Manufacturer’s Warranty
- Safe for fish and plants
- Remains flexible and pliable across a broad temperature range – from +170⁰F to -40⁰F
- Needs to be rinsed before use. Reports of manufacturing dust killing fish
For most pond liners, we recommend using an underlayment. Underlayments help prevent tears and punctures from tree roots and provide another layer of protection so that water doesn’t seep out. This underlayment has high tensile-strength, nonwoven polypropylene fabric that is easy to use. It is virtually indestructible and unaffected by hydrocarbons, mildew, rot, & freeze-thaw cycles.
Underlayments help to enhances soil stability and controls erosion while providing a stable and lasting foundation for water features and ponds. This underlayment is backed by a 20-year warranty,
- 20-year warranty
- Needle-punched nonwoven polypropylene geotextile fabric with a random, three-dimensional pore structure
- Virtually indestructible – resistant to hydrocarbons, mildew, rot, and freeze-thaw cycles
- Users report it holds up well and is virtually indestructible
- Expensive, especially in conjunction with pond liner purchase
- Requires an extra step in the installation
Pond Liner FAQs
How thick should your pond liner be?
The thickness of the liner will depend on the liner type. 45 mil EPDM is a safe thickness for reducing root penetration, but you can go with thinner with PVC. 45 mil EPDM is harder to fold into a tank and more expensive but lasts longer so there are trade-offs with every decision.
How do you line a pond cheaply?
Pond liner isn’t cheap which means that many people look for alternatives. Alternatives include Polyethylene liners, tarps, lime and clay covers, or waterbed liners. While most of these options will work to line your pond, they will not be as effective as a pond liner specifically designed for this purpose. You’re more likely to face issues around leaks, root and rock penetration, and the need to replace more frequently.
Can I use black plastic as a pond liner?
You can use black plastic sheeting such as landscape plastic to line a pond. However, the material will not last as long as other types of liners. It is more susceptible to punctures and tears, meaning that you will likely experience leaks over time. Additionally, some types of landscape plastic are toxic to aquatic plants and fish.
How long will a pond liner last?
The longevity of your pond liner will depend on the materials used in its construction. The lifespan of a flexible rubber or PVC pond liner can be up to 20 years or more. However, in order to achieve this level of longevity, the liners should be properly installed with an underlay. Some manufacturers offer warranties or guarantees on their product longevity.
Using a pond liner will help set your pond up for success by reducing the risk of leaks. Without a pond liner, you might wake up one day to find a pond with no water and some very unhappy fish and plant. Pond liners come in a lot of different options so it is important to know the pros and cons of your choice. Pond liners, like pond aerators, are essential pieces of pond equipment.
Our all-around favorite pond liner is the Firestone EPDM Rubber Pond Liner, 10-Foot Length x 15-Foot Width x 0.045-Inch Thick. It is durable and long-lasting, the two most important qualities in a potential liner.
What is your pond liner of choice? Have you used more than one type of pond liner historically?