Pond liner – HDPE or EPDM watertight liner for garden pond and aquaponics

HDPE liner close-up – thickness and durability of the liner for koi carp pond

HDPE liner three-quarter view – high-density polyethylene membrane for lasting waterproofing

HDPE liner top view – flexible material to roll out for setting up a garden pond

HDPE liner side view – rot-proof liner for aquaponic pond and small lake

HDPE pond liner

Name: HDPE pond liner
SKU: 663bd5e5-c7be-4b85-b708-c2aff8928211
Price: 21.9 EUR
Availability: InStock

21,90 €

This high-density polyethylene liner is available in 0.1 or 0.2 mm thickness and in two sizes, 3 x 2 m and 3 x 3 m. It unrolls flat and can be cut with a craft knife to line an already-built reservoir, buffer tank or grow bed.

Ref. 663bd5e5-c7be-4b85-b708-c2aff8928211·Pond liner

Dimensions and thickness : 3 × 2 m, 0.1 mm

3 × 2 m, 0.1 mm

3 × 2 m, 0.2 mm

3 × 3 m, 0.2 mm

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The summary

Thickness: 0.1 or 0.2 mm — that single figure is the only difference between the two versions of the same liner.
Sizes: 3 m by 2 m (6 m²), or 3 m by 3 m (9 m²).
What it's designed for: lining an already-built flat base — sump, buffer tank or grow bed.
Which size to order: the depth of the tank counts twice, both in length and in width.
How to choose: between this liner and thick EPDM, the shape of the base almost always settles it.
How it arrives: folded, lightweight, with the rest of your order.

Polyethylene film supplied on a roll, in 0.1 or 0.2 mm, two formats

The HDPE pond liner is a waterproofing film in high-density polyethylene, available in 0.1 or 0.2 mm thickness and in 3 x 2 m or 3 x 3 m sizes. With little elasticity, it does not follow contours: it is therefore suited to bases that are already flat, such as a reservoir, a buffer tank or a built grow bed.

This film is high-density polyethylene, available in 0.1 or 0.2 mm. It is a low-elasticity thermoplastic: it folds and cuts cleanly with a knife, but it does not stretch to conform to a contoured surface the way EPDM rubber does. It is therefore suited to lining a base that is already flat.

📏 Two sizes, two thicknesses

The liner comes in three versions: 3 m by 2 m in 0.1 mm, 3 m by 2 m in 0.2 mm and 3 m by 3 m in 0.2 mm. The thickness does not change the area covered, it changes what the liner can withstand, the 0.2 mm standing up better to the rubbing of a grow medium, the passing of a hand and repeated handling. Otherwise, the area should be worked out before choosing, by adding the length of the tray, plus twice its depth, plus a margin. A tray measuring 1.20 m by 0.80 m and 0.30 m deep already needs 2 m by 1.60 m of liner, margin included.

✂️ Where and how to position it

In a water-based system, this liner waterproofs the secondary volumes, whether the clean water reserve, the buffer tank where the water settles between two levels, or the base of a masonry or timber grow bed. These are flat-bottomed tanks, built before being waterproofed, where a liner can be laid in an afternoon. It also works very well for trialling a layout before committing to a permanent build, since you set up the tank, fill it, and watch how the water circulates over a season. The guide to building your own aquaponic system lists the equipment for a first system, from the fish tank to the grow bed.

Empty and sand down the tank

A protruding screw, a wood splinter, or a sharp block edge will puncture a thin liner.

Double the angles

Slip a felt pad or thick card into the sharp corners where the liner will be under the most stress.

Lay flat

Do not pull it. Form the corner folds by hand and press them flat against the side.

Fix above the water level

Whether you use clips, a batten or weights, the fixing point should always remain above the waterline.

Filling a growing bed without piercing the liner

If your lined tray becomes a grow bed, fill it with expanded clay pebbles rather than crushed gravel. Their rounded grains rest on the liner without any sharp edges, whereas angular gravel punctures it under the weight of the water. They are light to lift out when you empty the tray for maintenance, and they can then be rinsed and reused. Preferably lay them on the 0.2 mm liner, whose thickness withstands the friction of a grow medium better.

What can pierce a 0.1 or 0.2 mm film

Four things will puncture this liner: a staple placed below the water level, angular gravel dropped to the bottom, a pump placed directly on the liner without a pad, and a pair of secateurs left in the bed. A protective underlay beneath the liner and a mat under the pump deal with all four cases at once, and cost less than refilling the water. A leak shows up as a drop in level that stops at a certain height, and that is the height at which to look for the hole.

🧱 For built volumes

HDPE of this thickness is reserved for built structures, with a flat bottom and straight sides, rather than ponds dug into the open ground. As it does not stretch, it does not follow the contours of a hollow and gets punctured by the first stone poking up beneath it. Nor is it designed for permanent exposure to ultraviolet light, so an edge left in the sun becomes brittle over time and splits under the finger. Protect the exposed parts with a batten, a coping stone or a fold of grow medium, and you keep a flexible liner over the whole wetted height.

🔧 Repair and re-cut

A repair on this type of film is done dry, and that means emptying the volume. Dry the area, degrease it, then apply a patch of the same film extending well beyond the hole, using an adhesive made specifically for tarpaulins, as ordinary glue and site tape do not hold on polyethylene. A join between two sheets, on the other hand, will not hold up durably under a column of water: each volume is therefore lined in a single piece, in a size that covers it entirely. Keep the offcuts from your first installation in a corner of the shed; they will serve as patches and save you buying a whole roll for a few square centimetres. For a volume that needs to follow a dug-out shape rather than a built tank, turn to an EPDM liner, which stretches to follow the contours; if the volume can stay above ground, a raised pond with reinforced liner avoids the need for excavation.

Technical specifications

The essentials

Material: High-density polyethyleneA thermoplastic: it bends and cuts cleanly, it does not stretch.
Thicknesses: 0.1 and 0.2 mmThe 0.2 mm version handles grow medium abrasion and repeated handling better.
Formats: 3 x 2 m and 3 x 3 mThat is 6 m² and 9 m² before deducting the depth of the tank.
Cutting: With a craft knife, flatCut against a ruler and a board; the film does not tear along the scored line.

To budget for separately

Base protection: Geotextile fleece or thick cardboardEssential on a rendered or bare timber base, where even the slightest edge will puncture the liner.
Edge securing: Batten, staples, or ballastAlways above the waterline, as a submerged fixing punctures the film where pressure is applied.

In the box

1 HDPE liner, in the chosen size and thickness.

Material, thicknesses and sizes: product sheet, recorded on 20/09/2026. The areas given are those of the flat film, before deducting the depth of the tank.

HDPE or EPDM, two ways of waterproofing a pond

A thin film that lines, or a thick elastomer that moulds to the shape.

Torn between these two liners? The film is laid on an already flat base and cut with a utility knife. The elastomer is laid in a dug hole and stays there for years. Three questions are enough to decide.

	Thickness (mm)	Largest surface area available (m²)	Stretches to fit a hollowed-out shape	Price
EPDM pond linerYour choice	1 mm	35 m²	Yes	103,90 €
Recommended HDPE pond linerYour choice	0,2 mm	9 m²	No	21,90 €

EPDM pond liner

Thickness (mm)1 mm

Largest surface area available (m²)35 m²

Stretches to fit a hollowed-out shapeYes

HDPE pond linerRecommended

Thickness (mm)0,2 mm

Largest surface area available (m²)9 m²

Stretches to fit a hollowed-out shapeNo

Thicknesses, available sizes and material types: product data sheets, recorded on 20/09/2026.

Estimate your
delivery time

Thin and folded film: the parcel stays compact and lightweight, even in the largest format. It travels easily alongside the rest of your order. Exact shipping costs and final delivery times are displayed at checkout once your address has been entered.

Frequently asked questions

8 questions

6 key questions, 8 in the detailed view

Which thickness to choose, 0.1 or 0.2 mm?

How do you work out the size you need?

Take the length of the bed, add twice its depth and an allowance of around twenty centimetres for fixing, then repeat the same calculation for the width.

Bed, length x width x depth	Film required	Format
2 x 1 x 0.40 m	3 x 2 m	3 x 2 m
1.50 x 1.50 x 0.50 m	2.70 x 2.70 m	3 x 3 m

Can it be used in a pond dug directly into the ground?

Can two pieces be bonded together?

Is a geotextile membrane needed underneath?

Where to fix the edges?

Is it suitable for water containing fish?

How should I store it if I'm not installing it straight away?

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HDPE pond liner

The summary