How to Repair Hard Plastic Pond Liners

Drain the pond until the water level is lower than the crack. If the crack is low in the pond, you may need to temporarily remove the fish and plants.

Clean the area surrounding the crack with a clean, wet cloth. If you need to scrub with a bit of abrasion, use some dry salt. This will not be harmful to either your fish or your plants.

Use a blow-dryer to completely dry the area. Do not hold the dryer on the same place for too long and make it too warm. This could cause a larger hole in the liner than you started with.

Apply PVC sheeting cement to a repair patch and over the crack. Wait for three to eight minutes. The length of time you should wait depends on the air temperature. The warmer it is, the less waiting time. The glue is ready when it is no longer tacky.

Press the patch over the crack. Smooth it out so there are no wrinkles. Press it in place for at least 30 seconds.