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Troubleshooting Pond Leaks
Does my water feature have a leak?
There are some very simple, specific steps that must be taken to determine the cause of water loss. The possibility of a hole in the liner is way at the bottom of the list. The Good News is that there is usually a very simple solution to the problem. The Bad News is that it's finding the cause of the problem that poses the challenge.
90% of the time, the leak is in the waterfall and/or stream area.
It is usually due to some settling of the soil along the edge, especially if you notice the water level dropping after a heavy rainstorm. You can immediately look at the picture on the right, and see the area where the mulch is darker and saturated with water. This was an easy fix.
Step 1: Shut down the water feature. Fill the pond or basin to capacity before overflow. Note the water level. Leave it sit without running for a minimum of 24 hours; preferably 48 hours.
You should always provide additional aeration to the pond while the waterfall is not running. You can use "airstones," a "spouter," or an additional pump inside of the pond to help provide additional oxygen to the water. Just make sure that none of these options are causing water to splash outside of the liner area. Also, during extreme hot weather conditions I strong advise against shutting down your pond, because it can cause stress to your Koi.
Step 2: Check the water level. If the water level stayed the same, then there is not a leak in the pond or basin. Generally, this is the case, but we must rule out the pond or pondless basin first, before we can move on to any of the other steps. Move on to Step 3.
If the water level dropped (especially a couple of inches), then there must be either a hole in the liner in the pond or basin or the silicone seal on the skimmer plate (pond systems only) has deteriorated. Do not turn on the system. Continue to monitor the water level until it stops dropping. The hole or leak will be somewhere along the top of the water level.
If the water level falls below the "face plate" on the skimmer, then there is most likely a hole in the pond liner itself. Once the hole is located, it can easily be patched with an Aquascape liner patch. If the water level is within the area of the skimmer face plate, then go to Step 5.
Step 3: Turn the system back on. Inspect all of the edges along the stream and waterfall. Are there any wet spots? Move a few rocks here and there to make sure that the water is staying inside the liner. If you find an area that is wet, trace it to where the water is flowing over the liner. Lift up the liner and add additional soil or even a rock underneath the liner to prevent the water from flowing out over the top of the liner. You fixed the leak!
Also, check the area inside the stream or waterfall for excess debris, i.e., leaves, acorns, seed pods, blossoms, etc. Debris inside of the stream can sometimes build up and divert water over the edge of the liner (like a dam). Remove the debris by hand, which will allow the water to flow freely again down the stream without running over the edge of the liner. If this is the case, you fixed the leak!
If you cannot find any areas along the stream where the water is getting outside of the liner or any areas that are visibly wet, go to Step 4 for ponds or Step 6 for pondless waterfalls.
Step 4: For ponds only. Turn off the system. Check the silicone seal along the lip of the biofall filter. Add a bead of silicone in between the liner and the biofall lip. Re-foam the waterfall rock if necessary. Wait ½ hour for the silicone and foam to cure/dry. Restart the system. Check water level in 24 hours. If it stays the same, you fixed the leak! If the water level dropped, go to Step 5.
Step 5: For ponds only. Turn off the system. Check the seal around the skimmer face plate. Sometimes after many years, the screws disintegrate and need to be replaced. Sometimes additional silicone needs to applied around the skimmer face plate. And, we have also seen two situations, where the root of a plant grew up in between the liner and skimmer face plate and caused a gap between the two. Let the silicone cure/dry for at least a ½ hour. Turn the system back on. Check the water level in 24 hours. If it stays the same, you fixed the leak. If the water level dropped, go to Step 6. (The cost for replacing the screws around the skimmer face plate as well as resealing the face plate with silicone is $1,500; this work should be completed by a professional.)
Step 6: Keep the system running. Check the plumbing lines and connections. Dig up the plumbing line and check the plumbing connection (bulkhead fitting) on the back of the biofall to make sure that it didn’t crack. Inspect the plumbing line for any leaks from the biofall to the skimmer. If you find a connection that is leaking, turn off the system, and fix the plumbing connection and/or line. Let the glue dry for ½ hour. Restart the system. Check water level in 24 hours. If it stays the same, you fixed the leak! If the water level dropped, go to Step 7.
Step 7: Evaporation. If you’ve gone through all of these steps, and you are still losing water, then 3 things could be happening.
- Something was missed or overlooked in Steps 1 through 6;
- A large herd of deer is invading your pond every night and drinking your water (joking); or
Many factors can affect your rate of evaporation:
- Hot Sun and Temperature
- A Large Amount of Plants Absorbing Water
- Windy Conditions
- Length of Stream
- Pump Size
For an 11’ x 16’ pond:
- If you lose 2” of water in one day; it’s a leak.
- If you lose 2” of water in a week, it’s evaporation.
For a pondless waterfall:
- If you lose 4” to 6” of water in a day, it’s a leak.
- If you lose 1” to 2” of water in a day, it’s evaporation.
Here is a simple formula to determine the rate of evaporation for your water feature.
Formula: 1/2% to 1% of gph pump flow results in gallons of water loss per day.
- 2,000 gph x .5% = 10 gallons
- 2,000 gph x 1% = 20 gallons
- 4,000 gph x .5% = 20 gallons
- 4,000 gph x 1% = 40 gallons
- 8,000 gph x .5% = 40 gallons
- 8,000 gph x 1% = 80 gallons
First, take your pump size and determine the rate of evaporation using the above formula. Then, determine the surface area of your pond and the amount of inches of water you are losing.
For example, the surface area of an 11’ x 16’ with 1” of water loss.
11’ x 16’ x .08 x 7.48 (water volume) = 105.31 gallons
Now, compare the rate of evaporation for your pump size with the amount of water loss determined by the surface area of your pond. Are they close? If they are, it’s evaporation. If they aren’t, then it’s a leak.
I'm sure that after reading the above troubleshooting guidelines, you realize that troubleshooting a possible leak can be a lengthy and time-consuming process and that is why we provide these guidelines. We must work together as a team to eliminate and determine the possible cause of your water loss. Please be patient as we work through this procedure. We are here to help you, and we appreciate your daily feedback on your progress.
The cost of a service call for us to take a look at your system is $130 per visit minimum. Most of the time, we can isolate the problem within a few minutes (after Step 1 and Step 2 have been completed). If additional work is required, we charge $92/manhour plus materials in addition to the $130 minimum service call. Depending on the situation, there could be one to three persons involved on the site visit and repairs.
If you are unable to complete the above steps yourself (for example, digging up the plumbing lines, re-sealing the biofall, replacing bulkhead fittings), we are available to provide that service for you at the above-listed fees. Each visit is $130 service call for first 1/2 hour + $92/manhour beyond the first 1/2 hour + materials.