Pond Liners: Install The Right Kind

Garden Ponds Are Wonderful … Design Them To Be Trouble Free 🙂

Don’t Skimp On The Quality Or The Price When It Comes To Your Liner Choice

Garden pond liners … there are many choices yet quite honestly, little if any options if you don’t want trouble in a very short time-frame. Purchasing the wrong liner, whether made from too-thin material or inferior material is a big mistake!

You will NOT, I repeat NOT, save money in the long run if you try to cut corners in the area of your pond liner’s budget.

Choosing the Correct Liner for Your Garden Pond Is One of the Most Important Decisions You Will Make

Imagine having to take out an old liner to replace it when the pond is mature with blooming plants and filled with your pet fish. What an incredible hassle to deal with! Think of having to remove and safely house the plants and fish somewhere else, while you tear out and repeat the whole original installation process! No thank you … I’ll pass on this scenario!

Why put yourself through the horribly frustrating task of dealing with a leaking garden pond? For a few more pennies per square foot you can buy a premium grade liner. It is well worth the extra investment in the beginning. Tearing up an entire garden pond installation to replace the liner is 99.99% unavoidable if you understand the differences in liners.

Compare The Different Liner Choices

I’ll Give Yo An Overview Of The Most Popular Types of Liners Used

Key Features of Quality, Long-lasting Pond Liners

The #1 choice hands down is “fish safe” 45 mil EPDM rubber. Though there are a few excellent options for pond liners available to the water garden or Koi hobbyist, EPDM (Ethylene-Propylene-Diene-Monomer) is at the top of the list.

Do not settle for anything with less thickness than this. I cannot stress this enough. Also make sure it is labeled “fish safe”. I have no connection to Firestone, however one way you can be sure your liner is fish safe is if it carries the Firestone PondGard logo.

I personally have Firestone brand 45 EPDM liner in my Koi pond, which was installed in 2000 and it is holding up just like it is supposed to. It also carries a 20 year warranty.

Another important feature is EPDM is extremely flexible. This comes in handy when working with the irregular twists, turns, and shelves commonly found in a garden pond or stream installation.

EPDM easily drapes into the excavated area and conforms to all of the nooks and crannies in the application. EPDM is very stretchable and extremely resistant to punctures. It is also very flexible even in extremely cold temperatures.

Thinner rubber is more prone to rips or punctures during installation, and possible punctures on-up-the-road once installed.

Roofing Rubber is Not Fish Safe!

I do know of a few people who have bragged about saving a lot of money by buying the rubber used under roofing shingles. Please don’t use this stuff … to do so is a big mistake. Roofing rubber contains heavy metals and will kill your fish and stunt your plants.

Fish safe liners are given a stamp of approval by the manufacturer. This means they guarantee that the membrane is chemically compounded to be fish safe, and that it’s officially verified by testing to ensure that it is not toxic to fish.

Pond Liner Warranties

Don’t even consider using a pond liner if it doesn’t come with a long term warranty. Higher quality pond liners will usually come with a 20 year warranty. The warranties imply that the liner will not prematurely deteriorate because of weathering within the 20 year period.


Size Limitations to EPDM Pond Liners

The only limitation to EPDM pond liners is the largest roll size manufactured is 50ft x 100ft. For most of us backyard ponders, we will never need a piece this large. However that being said, here are a few seaming facts, so that you are informed. EPDM can be difficult to seam effectively because:

  1. Weather conditions have to be perfect in order to properly complete a seam.
  2. Moisture, such as rain or cold, damp conditions can affect seam quality.
  3. You need to have a good, flat foundation in order to perform the seaming process: driveways, yes … lawns, no.
  4. The edges where you will be seaming must be prepared by cleaning with unleaded gasoline.
  5. Seam tape can be very frustrating to work with. It wants to stick to everything, including you!
  6. Seam glue or “lap sealant” is also not always easy to work with.
  7. A hair dryer (extra heat) needs to be used in some of the steps for maximum adhesion of the new seams.

Now, this is not to say that many people and professional pond installation companies don’t have to sometimes seam together EPDM. Often this procedure is done in the situation where a stream bed section meets up with the pond liner section. I’m just letting you know it is not a fun nor easy task, but it is doable.

Other Types of Acceptable Pond Liners

I won’t go into a long discussion on the various reinforced polyethylene pond liners. These usually tend to be used in garden pond installations that require something bigger than a 50ft x 100ft piece. However, people do use this type for smaller installations. Some of the pros and cons are:

  • Flexibility, durability and fish safe features are inherent in this type
  • Custom sizes can be made by the factory
  • This type is much easier to seam, however a professional level of expertise is required
  • This type is not quite as flexible as EPDM
  • This type can cost a few more cents per square foot than EPDM
  • It may not hold up as well to “abuse” during installation of large stone placement around the pond.

In closing, there are many types of pond liners to choose from. Advertisements claiming “lighter weight” or “more tear resistant” are frequently seen in water garden publications. But in most everyone’s estimation, professionals included, the material of choice is 45 mil EPDM. Especially for those of us who are do-it-yourselfer’s, nothing else really compares to the quality, flexibility, strength, durability, and cost-effectiveness of EPDM.


  1. John Carston says:

    When it comes to pond liner manufacturers is there any one in particular that you would recommend? I will have to compare different liners by your recommended thickness and making sure it is EPDM like you recommend, but I was curious if you had a preference by experience. Thanks for the helpful pond liner post.

  2. Claudia Brownlie says:

    I would consult with a reputable supplier in your area for what liner would be appropriate for your particular situation.

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