The Pros and Cons of Preformed Pond Liners

Preformed pond liners are found at home improvement centers, garden centers, and through the internet. For someone new to ponds, these seem a viable option. They work best for small projects surrounded by many ornamental plants and other decorations to make a nice scenic view in the backyard.

My experience with preformed pond liners

My first pond before moving into my new house (which now hosts six ponds) was a second-hand preformed liner. Someone I knew used it for a single season and decided to drop it. The following year, I ended up with it. It was in fairly good shape with only a few minor scuffs. There were no holes to cause any leaking problems. I decided to have a little experiment with this preformed pond liner. I wanted to see if a pond could function properly without an electric pump, filter, or skimmer.

The Pros and Cons of Preformed Pond Liners
A plastic preformed pond liner may be the right choice for you depending on your situation and the room you have available to work with.

To make a long story short, my hypothesis was correct. With the right amount of oxygenating plants, snails, and fish, the water stayed completely clear. It indeed wasn’t necessary to add any electrical gadgets. However, the writing was on the wall with this pond. It was already old and beat up but I still accomplished my goal.

Problems with the neighbor

Eventually, an obnoxious neighbor threw a rock inside the plastic pond causing a large hole in the bottom which couldn’t be fixed. I actually was okay with that, my experiment was complete and successful. To be perfectly honest, I was getting ready to move out of that neighborhood anyway. I’m so happy that I did. The next property that I purchased had a larger house on a larger parcel. It had a place for me to put at least one large pond. I continued to work hard at the office and eventually got my wish (and then some). But that’s another story.

Installing a preformed pond liner

Here’s the tricky part. When it comes to installing a preformed pond liner you need to make sure that all the edges of the liner are level with the grade. While this may sound easy, it’s not as easy as it seems. A preformed pond liner has different depths. You must have your soil at the level of each of these indentations or your preformed pond liner won’t be even or level at the grade. I found this part extremely problematic. It takes patience, and with plenty of it, you can successfully install a preformed pond liner. There are other options and ways to do it. You could dig a hole and use bricks or cinderblocks on the lower levels so that the pond is even with the level of the grade. The most important thing of all is to have all the edges of the preformed pond liner perfectly level. Once you got that down, the hardest part of it is over.

Hiding the lip of a preformed pond liner

One problem I had with the preformed liner was properly hiding the circumference of the lip so that no plastic was exposed. I like a natural looking pond and I hate the sight of exposed pond liner, whether it be hard or flexible. The best way to do this is to get enough flagstone to place completely around the perimeter of the liner. Still, this won’t look as natural as a flexible pond liner. With a flexible liner, you have more room to work and more options.

While I haven’t tried it myself, it’s possible to place sod up against the lip of the preformed pond liner which makes it look fairly convincing. This is an idea I didn’t have at the time so I never tried it. Instead, I only used flagstone. All in all, it served its purpose. That purpose was to make sure that an ecosystem could thrive if set up correctly. More importantly, one that worked without any electrical add-ons.

Preformed pond liner add-ons

There’s actually a lot you can do with a preformed pond liner. I went a primitive way because I wanted to see if the ecosystem could function without any electrical contraptions. You, on the other hand, can add a waterfall or fountain to your preformed liner. This would give it an extra special effect and a certain aesthetic appeal that makes a landscape even more attractive.

There are several options. Many of these preformed pond liners have separate units which are smaller which snap onto the larger unit acting as a waterfall. In the case of having a small backyard with limited space, a preformed pond liner is sometimes the way to go. They are fairly easy to keep up. Just remember, the same rules apply to a preformed liner as with a flexible one.

Nuisance animals versus a preformed pond liner

One exception is nuisance animals such as raccoons. It’s much harder and more unlikely for them to chew through a hard plastic liner. Still, it’s not impossible.

Other elements that damage hard pond liners

Keep flagstone or any other type of stone or rock from falling into a preformed pond liner. Even when there’s water in it. Keep such stones up to only the lip of the pond. If any of them fall into the pond, liner damage occurs to the point of non-repair. It isn’t possible to fix a plastic preformed pond liner like a flexible pond liner. Once the damage is done and a leak is present, the pond’s life is over.

It’s a good thing these ponds are cheap. They also come in several different sizes and shapes. I’ve seen small ones that might carry 20 gallons of water. Larger ones carry up to 200 gallons of water. You have many options to choose from when it comes to preformed pond liners.

Is a preformed plastic pond liner right for you?

In the end, it comes down to how much space you have to work with. Some people have very small backyards with little space to work with. In such cases, either a small flexible liner or a plastic preformed liner will suffice. It seems as though preformed pond liners don’t have the life expectancy as other kinds of flexible liners. That doesn’t mean you won’t get enjoyment out of your preformed pond liner. Just be very careful of what you place around it. Remember, sharp objects that fall in cause cracks in these liners.

The cost of preformed pond liners

Again, these ponds are not especially expensive. On average, small ones go for under $100 while a larger one is just under $200. 

Is a preformed pond liner stronger than a flexible pond liner?

Generally speaking, no. Flexible pond liners last longer than preformed plastic liners. One may think the opposite is true since performed plastic liners seem harder. In actuality, most flexible pond liners are more durable and last many more years than preformed ones.


Depending upon the circumstances of your situation, a plastic preformed pond liner might be the right way for you to go. They’re also great for learning about ponds and how to build a proper ecosystem. It can ultimately be considered practice for when you make a larger pond out of a flexible liner. I’m actually thinking about working with a preformed liner again for a small project in front of my house. I’ll post my progress if I do. 

The Pros and Cons of Preformed Pond Liners