Larry, do you think that one of the deer has caused a small puncture with its hoof, as it fell into the pond?
Or one of the moles has caused a small tear in the liner?

There is a continuous leak in my ponds also that I cannot locate. If left alone, with no top-ups, the ponds lose about six inches of water over a three week period. Combined, they have a surface area of approximately 12' X 15'. The level stays at that lower point thereafter.

I have searched and searched, time and time again to locate the culprit, without any luck. I'm not as yet ready to go stripping all the stone work out from around the perimeter to find this small but annoying leak.

I use a timer set up to top up the pond early in the morning, so on a day to day basis I don't see the water loss.
It is only in the winter when I have shut everything down that the true effect is seen.

Sorry that I could not be more helpful, I do feel your frustration, it can be such an annoying elusive thing, plus the cost of the water top-ups.

In the summer with the "what you don't see........" attitude I guess I kid myself into believing that everything is fine.
Good luck with your quest to find the leak and when you do find it, please post an update. Maybe that will motivate me into doing something more about my situation. LOL
"Horton"

Larry - several posts over the years recommend pouring milk in the pond to locate a leak--theoretically the milk will swirl and you will see a flow toward the leak. Try it after the water has gone down to the leak level. I suppose you would need fairly still water for this.

Here's hoping the leak is in an easy location to fix.
Mike

Leaks can be sneaky to locate. A shallow shelf can be a place where some clawed animal stomped holes where sediment collects and masks it, it could be a cats claw slash going into the fold of a liner, a turtle that sheltered in the cover of overhanging plants, a sharp root that the liner settled on... A rodent pecking for water during Winter freezes, a storm tossed branched that lanced the liner and snapped off on impact.

The leak on the third pond helps that it is known to be at about one foot depth, you stand a chance of draining the pond and getting a patch on it without too much disruption.

If you shake say, a half cup of koi clay onto a couple of cups of water, going round the pond when the water is very still and dropping clouds of clay water in, the clouds of water might be drawn to where the leak is and indicate its location. That quantity of clay will be benign in the water.

Otherwise you are rather stuck with letting the water level drop to the level of the leak and keep plugging away at doing fingertip searches

Larry--I can't swear by the milk technique, but a search showed up several ponders suggesting it--pour around the edges, maybe short distances at a time. At one time it was the conventional wisdom here.

I have used cornmeal successfully twice to plug up small leaks. I think it gets drawn into a small hole, swells and possibly binds with fine soil particles under the liner. The leaks stopped for over a year. I posted this previously and the reaction was non-believing, sort of voodoo pond tending. Although one respondent noted that cornmeal was used to stop leaks in navy ship boilers during WWII. Same deal, sprinkle around the edges. Another one of those "what can it hurt for a couple of bucks?"

My guess is that losing 1-2 gallons per hour is too much for the cornmeal but should be enough to make the milk work.

Mike

Yes Larry it was the deer getting out of the pond part that I thought could have been when a small incision was made by a flaying hoof.

I have used slowly poured milk to find leaks and it can work.
I had a couple of leaks after installing the liner. They were due to folds in the liner acting as siphon tubes after a heavy rain had filled the pond to the brim.

Even after the level had returned to normal by draining out at a low spot,the water had kept going down over for few days.
This happened a few times until I decided to try the milk tracing trick.
I poured milk around the perimeter here and there and soon saw it coming out at a low spot onto the ground where a couple of folds in the liner came over.
I just pumped some silicone seal into the folds to plug them up and that cured that particular problem.
Hope this helps.
"Horton"

I have found and fixed more pond leaks than I can count. In this case I would lower the water level to about six inches below the leak. Get in the water and go slowly around the edge with a sponge and wash-cloth, sort of rubbing and drying and looking, up close.
Even if it's a pin-hole you will see it. Moisture comes through from the backside as you wipe/dry.

Thanks Bubba. I think this is the plan for me, except for that getting into the water thing. My water temp is right at 32 degrees on the surface right now. I'll give it try with my head hanging over the edge and try not to fall in head first like the deer.

Based on the leaks that you have found and fixed, what do you think is the most likely cause of a leak in a pond that started to leak after a decade of not leaking?

A plank across the pond can make it easier to search awkward places, saving a dunk in the water

ahah, remembered a few more techniques for finding leaks... Let the water level drop below the leak, wait for a very dry period of weather, go look by day and by night for little tiny beads of moisture showing up on dry areas of the liner where soil moisture is moving through small punctures.

You can spot pinhole leaks easier when the liner is very dry while the soil behind is quite damp.

During Summer, its not unusual to see tiny trails of debris trickling from punctures on a dry liner, ants find every tiny hole convenient for tipping out little particles of excavated soil as they extend their tunneling.

Rodents can be an occasional source of leaks, where in hard winters they cannot find water in frozen ground, they tunnel up to the liner and peck through the liner usually in out of sight places, beneath overhanging clumps of grass, folds in the liner... As their holes cause the water levels to drop, they bite new holes at another location lowering the water level further.

Where you can look behind the liner will indicate if their are rodents, you might anticipate several leaks along where those tunnels run after a hard freezing Winter. Moles do the tunneling, mice move in and bite at liners

larry,

sdavis, above is correct about the rodents. Also, a spot under the liner with no padding. One little pebble over time will do it. Dog claws, deer hooves, falling branches, etc. Sometimes you never know.

One of the more interesting ones was a bear. He got in a pond that was about the size, for him, of a giant bathtub. Proceeded to try and catch goldfish. There were giant claw marks everywhere. Replaced the liner.

Know anyone with fishing waders?

Also. There is this stuff called 'Rescue 911' that comes in a spray can. You can spray a few coats over a pin-hole type leak.

Bubba

I have a similar issue with my pond- will folds in the liner cause this issue of "wicking"? If so, I could just look under the liner fold and see if it is wet from wicking- can't imagine the water wicking that fast though

Mike,
I have been playing with liner ponds for the last 20 years and the last 13 years it has been my full time job. I have found and repaired hundreds of leaks in ponds and waterfalls. I have heard about wicking of water by the liner for all 20 years. I have never seen it happen. One winter during my slow time I spent over 40 hours trying to get water to wick up a liner. I tried everything I could think of to get it to wick. I ran over 70 experiments and I could never get the liner by itself to lift water even a 64th of an inch. I do not know if it is possible for liner to wick water but I doubt it. Yes it is possible to get liner to siphon water out but the siphon has to be started and this is not wicking. And it was extremely difficult to get it to even siphon with just liner. In order for a pond to loose one gallon per day it takes a hole loosing one drop per second. So depending on how much water a day that you are loosing will determine how big a hole you have to find.
Mike

I've just started having a problem with the top pond of my 2-level water garden leaking water. It started all of a sudden in early Jan. I was pleased when I turned off the pump that water only drained out about 7 inches down from the top, since my fish are all in the bottom pond. It never leaks beyond that level, and I've run my finger around it many times, finding no obvious holes. The pond is about 4 X 6', and will drain down to that level overnight, so it's relatively fast. I've just tried the milk idea, but I'd just refilled the pond, and the water level isn't yet back down to leak level, so I will try it again.

I have lots of folds in the corners, but I can pretty much get my finger into them, and feel no problems. The liner is draped over cement and rocks, which built up the walls above ground, so there's no wet dirt behind the liner, though I'll try the bit about draining it lower than leak level, and letting it get totally dry, then sponging, etc. This is maddening!

Don't know if you have solved the issue yet but thought I would make a comment. Wicking, can it happen? Yes. How does it happen? When a plant has roots both inside the pond and outside the pond you will lose water from the pond. A customer had a large umbrella plant next to their waterfall and after a number of times trying to find the leak I noticed that the plant roots outside the pond were saturated. We pulled the plant and found that the liner was high and dry but the roots were wicking the water out of the pond at an alarming rate. Once the plant was gone the water loss stopped.

Fatcataor: did the leak stop after you turned off the pump? if so look around your waterfall for possible settling/shifting of the stones. This is the most common reason for a pond leak.