Independent comparisons. We may earn from shop links. More info

How to repair a pond liner

Updated: 23 October 2026

The level has fallen, and you are about to buy a cartridge before you know whether the liner is the leak. How to repair a pond liner starts with that check. A pipe, a filter union or a waterfall spill can drop the same water as a split sheet. Once the level settles, you clean, match the repair to EPDM, butyl or PVC, and wait for the cure that listing prints. The [pond liner adhesive comparison](/hub/fillers-adhesives-and-sprays/pond-liner-adhesive) is the product table if you reach a cartridge. We used UK repair guides and the listing text, and did not lab-test a patched pond. A qualifying purchase can earn a commission at no extra cost to you.

The level has fallen, and you are about to buy a cartridge before you know whether the liner is the leak. How to repair a pond liner starts with that check.

Our top picks

MyPond MyPond MS300 black, 300 ml

Best overall

MyPond MyPond MS300 black, 300 ml
9.2/10about £15.99
View offer
MyPond MyPond MS300 clear, 300 ml

Best value

MyPond MyPond MS300 clear, 300 ml
9.0/10about £16.99
View offer
Oase Oase UniFix+, 290 ml

Rank 3

Oase Oase UniFix+, 290 ml
8.6/10about £27.83
View offer
On this page
  1. 1.Prove it is the liner
  2. 2.Mark, clean, dry
  3. 3.Patch or seam
  4. 4.Wait, then refill

Prove it is the liner

Top the pond up to a known point, switch off pumps, waterfalls and other features, and leave it overnight. GardenSite and Pond Planet both use that test. If the level is unchanged in the morning, the loss was pipework or the filter, not a hole in the sheet. If the level has fallen, the new waterline is where you look. Mark that line before you start hunting. Fish change the test. All Pond Solutions says not to switch filtration off in extreme heat or extreme cold. If the level is already threatening the fish, move them first. A leak that only appears when a waterfall runs is plumbing or a splash, not a reason to cut a patch.

Mark, clean, dry

When the level stops falling, the hole is at or just below that line. Walk the waterline, including folds and pipe sleeves, and mark the spot on the bank. Pond Planet’s note is the practical one: kits want the liner drained below the hole so the surface is clean and dry. Algae, talc on a new rubber sheet, and biofilm sit between the adhesive and the liner. Wipe the area, let it dry if the product says dry, and keep the patch larger than the damage. All Pond Solutions’ rule of thumb is a patch at least 5 cm larger than the hole on each side. If the bullets say to process it dry and above the water, this is the moment you drop the level. Wet-only work is on the underwater pond liner repair page. Do not seal a guess.
MyPond MyPond MS300 black, 300 ml

Testsieger

MyPond MyPond MS300 black, 300 ml
9.2/10about £15.99
View offer

Patch or seam

A small hole you can reach is a patch or a cartridge bead. A join between two sheets is a seam. Pondkeeper’s cold-glue kits are for their rubber liners, and they say those kits will not work underwater or on PVC. For EPDM or butyl, UK guides use primer and seam tape on a dry overlap, then a roller. The overlap figures are on the EPDM versus PVC page. PVC wants a weld, or a PVC cement for a short joint, which is how Oase separates those jobs. Bathroom silicone is the wrong tube on EPDM. If the sheet is creased and thin around a large tear, a new liner may be the repair.

Wait, then refill

The clock is the one printed on the product you used. MyPond’s bullets say 24 hours. UniFix+ says 24 hours in the spec and 24–48 hours on the bullets, after a dry application if you want the stated force. Pondkeeper’s advice is 24–48 hours, and a dry liner is the repair that lasts. One UK text on the black MS300 describes a liner-to-concrete bond that had fallen off by the next morning, which is why you do not refill early. A sound repair that still leaks means the hole was not the only hole. Call someone for a long buried seam, a hot-air PVC weld, or a stocked pond you cannot empty twice. Refill slowly, and only then put the waterfall back on.

Common questions

How do I know it is the liner and not a pipe?
Top the pond up, switch pumps and features off, and leave it overnight, provided the fish are safe. If the level holds, look at pipework, the filter and any waterfall that was running. If the level falls, search the settled waterline. A leak that only happens while a pump runs is not proved by glue on the sheet.
Can I leave the pump off overnight with fish in the pond?
Only if the night is mild and the fish are not already stressed by a low level. All Pond Solutions warns against switching filtration off in extreme heat or extreme cold. Move the fish if the water is already down to a dangerous depth. On a hot day, keep the filter running and look for the leak another way.
Should I use a patch, tape or a cartridge?
Use a patch or a cartridge for a small hole in one sheet, and primer plus double-sided tape for a rubber seam between two sheets. PVC cement is for a short PVC repair, and a heat weld is the proper PVC seam. The cartridge has to name a material your sheet actually is. A tube that only says rubber has not told you it is right for PVC.
How long do I wait before refilling?
Wait for the cure printed on the product in your hand. MyPond listings say 24 hours. UniFix+ says 24 hours in one field and 24–48 hours on the bullets, after a dry application. Pondkeeper’s guide also says 24–48 hours and prefers a dry liner. Filling early because the skin feels dry can lift a bead that has not cured through.
When is a repair the wrong job?
When the seam is long and buried, when PVC needs a hot-air weld, when you cannot empty a stocked pond twice, or when a sound patch still leaks. A large torn area can mean a new sheet. If you cannot name EPDM, butyl or PVC, identify the liner before you buy.

Related pages

Pond liner adhesive buying guide

Pond liner adhesive

Best pond liner adhesive: patch, named liner, skip

EPDM vs PVC pond liner adhesive: two different seams

Underwater pond liner repair: wet bead or dry seam

Sources

Public UK sources used for this comparison. amazon.co.uk prices, stars and review counts were taken from the listings captured for this set on 20 October 2026.

  1. Aqua Liners Direct, joining pond liner (retrieved 20 October 2026)
  2. Pond Liners Co, how to join two pond liners (retrieved 20 October 2026)
  3. Oase UniFix+ 290 ml (retrieved 20 October 2026)
  4. Pondkeeper, pond liner guarantees and repairs (retrieved 20 October 2026)
  5. Hutton Gold Label pond and aquarium sealer (retrieved 20 October 2026)
  6. Water Garden adhesives (retrieved 20 October 2026)
  7. GB CLP Annex II, retained Regulation (EC) No 1272/2008 (retrieved 20 October 2026)
  8. amazon.co.uk listings for the six ASINs in this set (retrieved 20 October 2026)