How To Find & Fix A Leak

Leaks can happen to any water feature, even if they are professionally built. Settling edges, burrowing animals, thirsty tree roots, or tunneling insects are just a few examples of things often out of our control as pond owners/installers. A leak should be dealt with as soon as possible because even if you have an automatic fill valve to keep up with it, the constant replenishing of well or city water can add excess nutrients which feed algae growth and dilute beneficial bacteria treatments, besides adding up on your monthly water bill.

First, it needs to be determined whether you actually have a leak or if the water loss is just due to evaporation. See our evaporation article to calculate what is normal for your specific water feature. It’s fairly typical for a pond to lose 1 to 1.5 inches of water per week just from evaporation. If your pond is losing more than that then follow the steps below to pinpoint where the leak is coming from.

Step 1: Take a close look around the stream/waterfall and pond for any obvious wet spots. The most common cause of leaks is settling at the liner edges which allows water to spill over the side. If you find a leak like this, usually the liner can simply be pulled up higher and secured by backfilling with more dirt, rocks, or gravel. If there are no obvious wet spots move on to step 2.

Step 2: Turn off the pump(s), fill up the pond to the maximum water level, and wait at least 24 hrs to see if the pond itself is holding water. (If you have an aerator it would be a good idea to run it so the water stays oxygenated for your fish.)

2a: If the pond is losing water with the pump(s) off, wait until it stops going down. Once it has stopped, the leak will be where the water level is now. 90% of the time the leak is likely to be where the skimmer is connected to the pond liner. Often plant roots or age has compromised the faceplate seal causing a leak. Contact AWM to reseal it.

2b: If the water level dropped below the skimmer's faceplate then there is likely a hole that needs to be patched in the pond. Or perhaps there is a seam of two separate liners in your pond that has failed. A search can now ensue where the water level stopped at. Special patch kits are available to repair holes in EPDM liner. Contact AWM to repair it for you or ask us for advice on how to do it yourself.

Step 3: If the pond itself holds water, then the leak must be coming from either the plumbing or somewhere in the stream/waterfall. It's time to start a process of elimination so you're not looking for a needle in a haystack.

3a: ​To isolate the plumbing you can often cap off where your pump connects and then fill up the biofalls (if you pond has one). If that water level goes down over the next day or two then it's very likely the leak is in the plumbing. *Very rarely, a leak could be happening in the plumbing only when it's under pressure.

3b: While the plumbing test is happening, the waterfall itself can be tested. An external pipe will need to be attached to the pump and run up to the bottom most level of the waterfall. Run the pump for a day or two. Move up the next step if there was no leaking. Repeat the process until you reach the level at which it begins leaking. Now this area can be thoroughly searched for holes, low liner edges, or faulty seams and be repaired.
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3c: If the plumbing is holding water and you've moved your test hose all the way up the entire waterfall without finding any leaks, then the last possible place could be the connection between the biofalls and the liner. This seal is made with silicone and can fail over time due to improper installation, age, or roots breaking through. Often it's best to contact a pond professional to reseal this connection.