Every pond needs some kind of liner to help prevent leaking, erosion, and outside contamination. However, before you just choose the standard product, remember that there are lots of different options and alternatives for pond owners to consider.
Materials like concrete, tarps, deflated pools/waterbeds, natural clay liners, butyl, and multiple variations of polyethylene (including high density, low density, reinforced, and flexible) can all be used as pond liners.
Polyethylene is the main material that is used for pond liners, but there are a lot of other alternatives available as well. Each of them have their own pros and cons, which will be explored in more detail below. A few top-rated products will also be covered.
Pond Liner Alternatives
There are many different materials that can be used as pond liners. They come in a variety of shapes and sizes, and some of them will work better than others for different pond setups.
Be sure to look at the pros and cons of each one before deciding which one would be best for your water feature!
HDPE (High density polyethylene)
Different variations of polyethylene are popular choices when it comes to pond liners. Each one is a bit different, but high density polyethylene is a strong contender on this list!
This is a stiff, strong material that is extremely resistant to chemicals and UV radiation. For a pond liner that’s going to be exposed to the sun every day, this is an important quality to have!
HDPE is very durable and can last for over 30 years when it’s properly installed and maintained. It also holds up well during cold weather, which is handy for outdoor ponds that may freeze in the winter.
Unfortunately, this is also not a very flexible option. It usually comes pre-molded, but it can be welded to make it somewhat more adaptable. It’s also quite heavy, and although it’s durable, it can still be punctured or cracked under heavy stress.
LLDPE (Low density polyethylene)
Low density polyethylene shares many of the same qualities as its high density counterpart. For instance, they’re both safe for fish, have similar temperature resistance, and will last for about the same amount of time under normal circumstances.
However, low density polyethylene has a few major differences as well. One of the biggest factors that sets it apart is its flexibility! While HDPE is quite rigid and stiff, LLDPE can be stretched and folded to conform with the unique shape of a pre-existing pond.
Due to this pliability, it also won’t crack as easily under stress. However, as a trade-off, this material is less chemical resistant than HDPE. UV radiation, oxidation, and other chemicals can break this down over time, although it can still last for 36 years under proper conditions.
RPE (Reinforced polyethylene)
Reinforced polyethylene is kind of a hybrid between HDPE and LLDPE. It has some of the best qualities of both, as well as a few improvements!
As the name might suggest, RPE is reinforced, so it’s stronger than the previous two options. It’s one of the thinnest options on this list, but also one of the hardest to tear or puncture.
RPE falls in the middle when it comes to flexibility. It’s harder to maneuver and conform than LLDPE, but much less stiff than HDPE. It also still has the chemical resistance and fish-safe benefits of the other options.
These benefits come with a price though. Literally! Although RPE has many of the combined benefits of both previous polyethylenes, it’s more expensive.
Because they’re fairly new to the market, their lifespan is not certain either. They also may not last as long as their counterparts, but they should hold up for at least a couple years.
fPP (Flexible polypropylene)
Flexible polypropylene is one of the most pliable materials on this list. It can easily conform to the nooks and crannies of pond bottoms without tearing or splitting. If you’re dealing with a pond with lots of rocks and boulders, this could be the right choice for you!
In addition, fPP is quite heat resistant. It doesn’t expand or contract much in heat or cold. It should remain flexible in a wide range of temperatures and doesn’t require treatment to stretch it out.
fPP is resistant to UV radiation and many chemicals, but it is vulnerable to hydrocarbons, chlorine, and oxidants. If these are commonly used in garden ponds, this material could wear down and crack over time. This usually isn’t the case, but it’s something to keep in mind.
PVC (Polyvinyl chloride)
I don’t know about you, but when I hear “PVC” I think about the small white tubes! However, polyvinyl chloride is a classic material used for pond liners.
PVC is very cheap, which might make it an attractive option if you’re on a budget or dealing with a large pond! It also has a similar level of flexibility to fPP, which means it can fit snugly against a variety of surfaces without issue.
PVC is also resistant to a lot of chemicals and is easy to weld, tape, or glue. Unfortunately, it does come with a few drawbacks. PVC is not a fish-safe material and can end up emitting toxic chemicals into the water. If it isn’t covered, it can also break down under UV radiation.
Temperature is also a weakness of PVC. It can crack under high or low temperatures and probably won’t hold up well during a winter freeze.
EPDM (Ethylene propylene diene monomer)
Ethylene propylene diene monomer is a long title, but this product is a fantastic option for a pond liner! This is a synthetic rubber material that has a great ability to stretch without tearing.
Because of its flexible, rubbery texture, it can withstand temperature differences quite easily and is strong without being brittle. It also has a long lifespan (more than 20 years) and is resistant to UV rays.
Unfortunately, EPDM doesn’t have very good chemical resistance and can’t be easily welded. It’s also fairly heavy and can be hard to transport and install. With shipping costs included, EPDM can end up being fairly expensive.
In many ways, Butyl is similar to EPDM. It’s another synthetic rubber material and has the same qualities of flexibility, long lifespan, and temperature resistance.
Butyl is also fish-safe and non toxic. As a bonus, it’s also quite cheap and easy to get a hold of in the US.
Unfortunately, Butyl can’t be welded without degrading the quality. It’s also a bit less durable than other options and can be scratched or torn fairly easily.
For more information about Butyl, PVC, EPDM and the polyethylene materials discussed above, visit pondinformer.com
Natural Clay Liner
If you’re looking for a more organic solution when it comes to pond liners, you may want to consider using clay and lime covers. This is similar to how ponds and lakes will actually form out in nature.
Generally you’ll want to start with a layer of limestone, covered by another layer of compacted clay. The combination of these two materials is called “lime concrete”.
Lime concrete is waterproof when formed correctly, and it’s pretty durable as well. These materials could eventually become eroded or mixed over time though, so clay pond liners may require a bit more upkeep than others.
Clay liners can also dry out and crack if you drain your pond. Some amount of silt and debris in the water should also be expected.
Concrete is another popular choice. It’s frequently used in swimming pools of all sizes, so it’s been proven to keep water in!
Concrete is a good material for large, open, long-lasting ponds. The material is strong and highly durable against erosion. Because of this, concrete ponds will become a permanent feature of any yard they are installed in. This can be positive or negative, depending on whether or not you plan to make other changes in the future.
It’s also a low-maintenance material and can last for over 50 years! On the downside, concrete can be quite expensive and it will need to be professionally installed and cured. It also is too rough for most fish and plants, so a second pond liner will be needed to soften it.
Tarps are commonly used by pond owners who are on a budget. Because tarps are waterproof and flexible, they are cheap alternatives to the other options on this list.
Tarps are cheap, widely available, and easy to set up at the base of a pond. Many people like to overlay multiple tarps on to of each other to get better coverage.
However, tarps are not the most durable option. Tarps can easily become damaged by the sun, which will lead to them tearing or thinning in certain places. They function best in deep ponds where they won’t be expose to the sun.
Inflatable Pools And Waterbeds
Finally, we have the option of inflatable pools and waterbeds! Recycling the waterproof base of pools and waterbeds can be a great way to reuse these parts. If you already have one of these items on hand, it also won’t cost anything extra to get ahold of them!
Like the other options on the list, pool and waterbed liners are designed to be waterproof, and are flexible enough to conform to the bottom of a pond. Unfortunately, due to their size, these liners are only good for small, decorative ponds.
They won’t work well for a large area, and their materials are not fish-safe. In addition, these aren’t very durable for outdoor use and will break down over time.
Thinking of attaching your pond liner to wood? We got you covered. Check out our article Step-by-step: How To Fix Pond Liner To Wood.