A pond liner is an essential part of any pond. While the ground will eventually stop leaking water and become relatively watertight, it takes time and isn’t exactly predictable!
That’s where a pond liner comes in. It’s a watertight shell or material designed to form the base of a pond and keep water at predictable levels.
Use a pond liner and you’ll be able to relax knowing your fish will always have water and that you’ll need minimal maintenance to retain water levels.
But what are pond liners made out of? What are the pros and cons of each option?
Those are the questions we’ll be tackling today.
What is a pond liner made of?
Pond liners are predominantly made from PVC, HDPE, Butyl, EPDM, and rubber. They can be hard or soft, shaped or sheet.
Each has its advantages and disadvantages and ideal use cases.
Some PVC pond liners are shaped into the shape of a pond and are not flexible. Some PVC pond liners can be more flexible, but not as flexible as other types.
HDPE, High-Density Polyethylene is a polymer made from thermoplastic. Like PVC, it can come as both hard and soft pond liners and is very hard-wearing.
Butyl is a type of rubber used in tires and inner tubes. It’s light, soft yet very hard-wearing, and is ideal as a pond liner.
EPDM, Ethylene Propylene Diene Monomer, is a type of rubber often used on roofs and in construction. It’s another flexible, pliable material that lends itself well to being a pond liner.
Finally, RPE, reinforced polyethylene is another common material used in pond liners. It’s plentiful, pliable, and water-resistant.
The pros and cons of pond liner materials
So, we know the what, now let's dig into the why. Let’s discuss the pros and cons of each material.
PVC pond liners
PVC pond liners are common and cheap, which makes them ideal for use in DIY projects.
Pros of PVC – PVC is very plentiful and very cheap. It’s also flexible in some forms, making it ideal for a pond liner. It is also resistant to chemicals, easy to install, and can be easy to handle.
Cons of PVC – PVC can also be dangerous to fish in some forms so make sure to check before you buy. It is also susceptible to UV radiation and weather so needs to be protected.
HDPE pond liners
HDPE pond liners are commonly used in larger ponds and small lakes. It’s a common material used in hundreds of applications.
Pros of HDPE – It’s cheap, strong, and stiff. It’s also waterproof and can be installed relatively easily by a pond installer. HDPR is also chemical resistant, UV resistant, and very durable.
Cons of HDPE – Notice we said ‘by a pond installer’? While a DIY pond builder could use HDPE, its stiffness makes it difficult to shape and work with. This could cause issues if you’re planning to install it yourself.
Butyl pond liners
Butyl pond liners have been used for gardens for many years and are a well-known material for this use.
Pros of butyl – Butyl is very pliable and easy to handle it can be cut easily and molded into place with minimal effort. It is also temperature and UV resistant and is safe for the majority of fish.
Cons of butyl – Butyl is difficult to seam, so joining pieces together can be challenging. Butyl is also susceptible to punctures and tears, so the materials you use in your pond need to be carefully considered.
EPDM pond liners
EPDM pond liners are exceptionally popular as they are plentiful, pliable, and resistant to many things.
Pros of EPDM – EPDM is soft and very flexible, making it easy to shape. It’s also very strong, temperature and weather resistant, and safe for fish.
Cons of EPDM – EPDM is also hard to seam, which could make joining pieces together a challenge. EPDM is also more susceptible to chemicals and solvents, so careful handling is paramount. Finally, EPDM is more expensive than HDPE or PVC.
RPE pond liners
RPE pond liners are another common option for ponds. RPE offers many of the advantages of HDPE, with fewer downsides.
Pros of RPE – RPE is durable, pliable, and easy to handle. It’s also very resistant to punctures, relatively easy to seam, resistant to UV light and most chemicals, and safe for fish.
Cons of RPE – RPE is slightly more difficult to handle than butyl or softer PVC liners. It is also more expensive and, because it’s relatively new, hard data on longevity has yet to be developed.
There are other materials used in pond liners, rubber, fPP, and so on, but the above are the most common. They are also the most available, so it makes sense to choose one of these.
Is there a ‘best pond liner material'?
As you can see from our outlines, there is no ‘best’ pond liner as each has its pros and cons. Much will depend on whether you’re building your pond yourself, need to shape the material, or seam multiple pieces together.
As long as you buy quality, you should only need to buy once. Some materials will even come with a lifetime guarantee, which should be all you need to know!