PVC pond liners are durable pond liners for your back garden pond. Over time, with wear and usage, a PVC pond liner may develop a rip or tear and need to be repaired. If the rip or tear is not repaired, the water will leak out of the pond and depending on how bad the leak is, the pond could empty fairly quickly. Also the leaking water could damage any nearby objects that aren't meant to get wet. Luckily, it is fairly easy to repair a PVC pond liner, and it is not very costly or time consuming.
Drain the pond down below the area that is damaged to expose the damaged area above water. A submersible pump works great for fast draining. You won't be able to repair the PVC pond liner underwater.
Scrub the area clean. Make sure you remove all the algae from the surface. A brush or wet drag dipped in dry salt works great because its naturally abrasive and won't harm your pond life.
Use a blow-dryer or hand-held propane torch to dry the area and warm it up. Be careful if you use a propane torch, as too much heat in one location could burn a bigger hole through the liner.
Buy PVC sheeting cement and a patch from your local home improvement store. The cement you want is used to glue white shower stalls. It's not the PVC plumbing pipe cement.
Cut your patch to desired size. It should be slightly bigger than the damaged area so it can make the proper seal.
Apply one coat of glue to both the liner and the patch. Allow to dry for 3 minutes at 26.6 degrees C (80 degrees F) for 8 minutes at 10 degrees C (50 degrees F). The patch will not be tacky when ready to be applied.
Apply the patch and make sure no wrinkles are present. Hold pressure on the patch for 30 seconds and your PVC pond liner is now patched as good as new.
Refill the pond to your desired water level.
Try to locate the cause for the liner damage. If the cause is not removed, the liner will get damaged again and need another repair. Depending on the location of the damage, you may need to remove your fish to get at the damaged portion of the liner. Have a temporary location that they can go to while you repair the liner.