Can You Use a Tarp as a Pond Liner?

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A neat and well-kept pond is an impressive feature of any garden. Whether you want to keep aquatic plants or fish, you’ll need to safely structure your pond. A pond liner is vital for a long-lasting and stable pond. 

Not all tarps can be used as pond liners. Those that can be used, need to be waterproof, thick, and UV resistant. Some cheap tarps are not fully waterproof when used in a pond. However, you can use a vinyl tarp as a pond liner. It is tear-resistant, UV protected, and waterproof. 

A vinyl tarp will not only contain water in your pond, but it will also help keep debris out for easier maintenance.  Furthermore, to add an additional layer of protection for your liner, an underlay is a good idea. An underlay offers a cushion between your pond base and the liner, and is strong enough to keep sharp objects and tree roots from puncturing the tarp. Read on to learn how to calculate your pond liner size and more.

Choosing UV-Resistant Pond Liners

Pond liners can crack when exposed to the weather and elements for a long period of time. Therefore, you should install a liner that is resistant to temperature, sunlight, and ultraviolet rays. Also, a pond liner that is UV resistant is durable and lasts for many years.

About Tarp

Some tarps can be used as pond liners because they are reinforced with polyester. The polyester that is used has anti-leakage properties. The tarps have a polyethylene coating over polyester or canvas. The polyethylene layer makes these tarps waterproof, and polyester or canvas makes them strong. 

Vinyl tarps can be used for lining ponds. They are built to last and heavy-duty. These tarps are designed with abrasion and water resistance properties. In fact, they can resist grease, oil, acid, and mildew damage. 

A vinyl tarp liner helps your pond hold water and gives it structural integrity. It helps keep the plant life and fish in your pond thriving and protected. 

Vinyl Tarp Pond Liner

This pond liner from Billboard Tarps that can be found on Amazon, is a heavy-duty tarp that has a 3-ply coated vinyl. It is tear-resistant, anti-mildew, and UV protected. It is 100% waterproof, preventing water from seeping out into the ground. The liner is fish-friendly, and it does not leach dangerous chemicals into the water. 

What’s great about this tarp is that it is suitable for ponds of all sizes. The vinyl tarp is 22 mils thick. Also known as thou, one mil is equal to 0.001 inches (0.0254 mm)—the thicker the tarp, the better the quality. You can trim this pond liner with very little fraying. Made for use in all weather conditions, the tarp keeps your pond well-maintained and water retained.  


  • Tear-resistant, anti-mildew, and UV protected 
  • Fish and plant safe
  • 100% waterproof
  • Heavy-duty tarp with 3-ply coated vinyl
  • Easy to modify and trim

Why Do You Need an Underlayment?

It’s important to know that the tarp should not be directly used on the pond’s base. Instead, an underlay should be laid on the base.

Here is why you need an underlayment.

Protection Against Stones and Rocks 

When you dig down through the topsoil, you will often see that the soil becomes more uneven and rough as you dig down. You will quite often uncover several rocks and stones. This debris can be troublesome if you’re just laying down the tarp for your pond because sharp objects can often puncture through. The underlayment protects the tarp against any damage by sharp stones and rocks.

Prevention of Pesky Root Growth

If you plan to construct your pond near plants with strong roots, you will certainly need an underlay beneath your tarp as the roots could push right through the liner.

Reduction of the Stretching Process

An underlay also helps decrease the excessive localized stretching of the pond liner when ground settlement happens over time.

Beckett Corporation Pond Liner Underlayment

This underlayment on Amazon from Beckett Corporation ensures that rodents, sharp objects, and rocks do not damage your tarp. It is made of polypropylene that creates an ecologically friendly environment for fish and aquatic plants. You can easily place this underlayment within your pond area. The underlayment keeps your tarp in place for a long time.


  • Easy to work with
  • Good quality
  • Protects the pond liner from leaking

How Much Tarp Do You Need?

Before setting up the tarp, you need to determine how much pond area you need to cover. Dig the pond to get the measurements.

To determine your tarp’s size, you should know your pond’s depth, width, and length.

Tarp length = pond length + 2 x (pond depth) + 2

Tarp width= pond width+ 2 x (pond depth) + 2

How to Install the Tarp?

Here is how you can install the tarp in the pond:

  1. Before installing your tarp, make sure that you’ve removed all sharp objects, such as sticks, roots, and rocks, from the pond base and walls. If you’re not able to remove a sharp object, put down a layer of sand or soil first to level things out. 
  1. Next, lay your underlay on the pond base and all sides, positioning the tarp in place once all areas are covered. 
  1. Should you need to tread on the tarp, remove your footwear to avoid piercing. 
  1. Finally, secure the tarp in place around the outside edge of your pond.
  1. Slowly fill your pond with clean water, gradually adjusting and pulling the tarp to ensure a neat finish and wrinkle-free edging. Fill it and then leave overnight to settle. 
  1. Trim off any additional liner the next day, leaving 30 cm (12 inches) overlap at the edge.

Maintaining the Tarp and Pond

Once you’ve installed your tarp, it will keep the pond functioning effectively. However, to keep the pond in tip-top condition, you need to maintain it. Spring would be a good time to clean the tarp and the pond. Clean up your tarp and the pond of waste and sediments that could have settled at the bottom of your pond. 

In addition to this, you should regularly remove algae from your pond as much as possible. You can remove any unwanted algae or sludge easily and quickly with the help of a pond vacuum. 

You might want to check out the OASE PondoVac Classic Pond Vacuum (link to Amazon). With a versatile design, this pond vacuum can handle a variety of medium to small-sized ponds. 

Make sure to scrub the sides and bottom of your tarp and rocks to loosen algae. During the summer months, the level of water in the pond would drop due to evaporation. So, add water to your pond regularly.

In addition to this, you’ll need to clean your filters and pump regularly and check them for any clogs.

You should also check your fish for signs of ill health, such as different eating patterns, sores, and slow movement. Unhealthy fish are a sign of poor water chemistry in your pond. Too much ammonia, chlorine, and other chemicals can hurt your plants and fish.

If muck and algae build up in your pond, drain your pond, wash off the tarp, and refill your pond. Adding barley straw and biomass filters to your pond might help keep algae away. Drain your water lines, drains, and pumps of your pond when it is not in use.


A pond in the backyard creates a beautiful and calm environment. It is wonderful with aquatic life and exotic fish, but it does need care and maintenance. A proper liner is the best type of care for this type of structure. 

It’s important to note that not all tarps can be used as pond liners. Some are only water-resistant and not waterproof. So, choose tarps that are thick and waterproof.

The most used type of liner is a tarp that is heavy-duty and strong enough to keep your fish and other pond inhabitants safe. Moreover, heavy-duty tarps are tear-resistant, waterproof, easy to manage, and light in weight. In addition to this, they are mildew resistant and have a required thickness to decrease wear and tear.

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