Once your pond has all the finishing touches, whether those are underwater lights, a waterfall, and blooming plants, and it has cycled and welcomed its first fishy residents, it’s time to understand how to maintain the liner so that your pond is worry-free and leak-free for decades to come.
Fortunately, EPDM liners are durable and naturally resist the deteriorating effects of sunlight, ozone, and other weathering. Your primary jobs will be protecting your liner from avoidable physical damage such as abrasions, punctures and tears, and promptly repairing any damage that does appear.
Wildlife visitors can be responsible for all three types of damage, whether they’re hunting for tasty fish, stopping for a quick drink, or simply digging and scratching to see if any tasty bugs are about. You may choose to install fencing to keep out unwelcome wildlife, or you can protect the borders of your pond with a thick layer of river rocks, or other relatively smooth stones that are too heavy to encourage digging. Check online for a host of other solutions.
Humans can be a source of damage to your liner - curious kids may go digging around and wonder what that corner of rubbery sheet is. Your clumsy uncle may stumble and knock the wrought iron table directly into the pond. Even your careful efforts to remove a large tree branch dropped during the last storm may result in some scratches or a puncture or two.
If you do end up with a leak, whether you know how it happened or you simply deduced it from a slow but steady drop in your pond’s water level, patching an EPDM liner can be a reliable solution, but since the liner must be dry to work with, cross your fingers that any problems you encounter are not on or near the bottom of the pond.
Your first task is to identify the leak (or leaks), and that can be an adventure in itself. Check out some online hobby sites or consult your local pond supplier, for options, but most leak detection methods are simply variations of two strategies: leveling the water and using dye. We have a helpful article explaining how to employ these strategies.
The more serious, and deeper the damage is located, the more seriously you may want to consider simply replacing the whole liner. If you’ve gotten plenty of good years out of it or if you’ve been hankering to make some upgrades, a complete renovation may just be altogether simpler than facing the chore of having to completely empty your pond in order to locate and patch a hole, or even a series of holes.
If you’re lucky to find a single or even a couple of small holes and you’re confident there are no others hiding in the shadows, they can be easily patched with some primer, adhesive, and a liner patch. These materials are widely available in repair kits designed specifically for EPDM pond liners. It’s best to stay away from general purpose patch kits used for EPDM in general, since you can never be sure the components will be entirely fish safe.
Patching a hole in your EPDM liner is a five-step process:
- Drain your pond so the water level is about 12 inches below the hole. If it is pretty deep, you may need to house your fish elsewhere for a few hours. Don’t forget to provide an aerator in their temporary tanks! If your bio filter is going to be exposed to air, consider moving it to a holding tank as well to prevent a die-off of all your beneficial bacteria.
- Once the hole and surrounding liner is exposed and dry, thoroughly clean the liner surrounding the hole, about 4 inches in all directions. An all-purpose household cleaner will work to remove algae and other contaminants, but be absolutely sure that none of the cleaning solution drips into your pond water and that the residue is completely removed from the liner material.
- Once the patch area is clean and dry again, prime the area surrounding the hole with the primer included in your patch kit. Follow the directions on the container for best results.
- Cut your patch into a circle, being sure to allow a generous overlap for the patch to grip undamaged material. A circle is recommended to prevent sharp corners from peeling up.
- Use a roller to apply the patch. Work over the patch thoroughly, from the center outwards, while applying stiff pressure to work out any air bubbles and ensure complete adhesion.
- Allow the newly applied patch a few minutes for the adhesive to set.
- Refill your pond.
