If you are one of the fortunate few who have never had to look for a leak in your pond, quickly find a piece of wood and knock on it. But remember, your day may come, so here’s how to tackle the problem when it arrives.
First you must determine if you truly have a leak or if you are just experiencing evaporation. All ponds will lose water to natural evaporation. Ponds with larger waterfalls, thus more splashing, may tend to lose more water than ponds with quietly meandering streams. Unless Mother Nature provides enough rainfall to replenish this water loss, you will have to add water to your pond. Ponds can lose anywhere from 1 to 3+ inches of water in a week depending on individual pond characteristics and circumstances. So, how do you know if your water loss is normal?
DIAGNOSIS: If you are a new pond owner it may take a while for you to figure what your pond normally loses in a weeks time. For those of you who are veterans, you know what to expect from your system. It’s very similar to going to the doctor and saying I feel a little “off” but I don’t know exactly what’s wrong. The doctor will start eliminating possibilities by asking questions. Which is exactly what you are going to do with your pond.
It’s best to have a benchmark from which to gauge your ponds water loss. Pick a rock in your pond to use as the “bench mark”. When your pond is filled to where it should be, check to see where the water level is on the rock (remember that the rock will actually be wet a good 1/2″ above the waters surface due to the wicking action of the stone itself). Now you have a benchmark. If you feel that at the end of one week you have lost more water than normal, start the search. The majority of all leaks on newer ponds are found along the edges of the pond, streams or waterfalls (very few leaks are actually punctures in the liner). Older ponds may have problems with their components – which we will addressed later in this information sheet. Some causes of leaks are: shifting stones; soil settling after a freeze/thaw cycle (winter); a stream becoming clogged with leaves; or excessive plants in the stream or biofalls. The best method to look for this type of leak is to walk the perimeter of the pond (including the biofalls and skimmer) and look for excessively wet areas in the soil or mulch. If you find such a spot, determine what the cause is. Is the liner too low at that point? Is there excessive splashing from the falls? Has something (leaves or rocks) caused the water to divert away from the main flow of a stream? If no obvious wet spots are found and you are sure that you are losing too much water (say, 1 inch per day) the job becomes a little more time consuming. NOTE: In Pondless water features with long streams you may experience 1″ of water loss per day and this may be normal. The reason is that the surface area in the basin of Pondless systems is smaller than a normal pond. Thus, a 10 gallon water loss in a pond would not be noticeable, but in a pondless system it might drop your water level down an inch or more.
First you must determine if the water loss is coming from the stream, the falls, the pond itself, or the equipment/plumbing. At this point, shut down the pond pump(s) and make note of the water level in the pond using your benchmark. (It’s a good idea to fill the pond back up to the proper level, being sure that you don’t fill it too full and have water spilling over the edges of the pond). Now let it set 24 hours and come back and check the level in the main pond. If it has stayed the same then you can be pretty sure that you are not losing water from the main pond. If it is down, continue monitoring until it has gone 24 hours without water loss. Once it stops dropping you at least know at what level your leak is located. The first place to look is around any areas of the liner that have been cut in order to install a component such as a skimmer. Areas such as these are prone to leaks especially after they have been running for 5 or more years. The silicone can get bad or the screws can corrode and cause the faceplate on the skimmer to leak.
If after checking these areas you still can’t find the leak there is one more item to check before getting real dirty. Go another 24 hours and then look inside your skimmer box and see if the water level in the box is lower than the water level in the pond. If it is, there is a good chance that your skimmer box has a crack in it. Once the water level in the skimmer box has stabilized you will more than likely be able to see or feel the crack. If there is a crack, it can be repaired (at least temporarily) using a good waterproof epoxy. The other option is to replace the entire skimmer. At this point you might want to contact a professional.
If the water level in the skimmer is not suspect then you will need to get dirty. If you have a bare rubber liner with no boulders along the walls, just go along the edges at water level and look for your hole. If your pond is a more “natural” looking system with boulders along the inside walls you will need to start by removing the rocks lining the inside walls of your pond. Remove them down to a point just below the water level and begin looking for the hole at the water level. It could be on the vertical side walls or it could be on a horizontal flat surface. If you have any big boulders with their bases at the same level as the water, lift them up and check for tears or cuts under them. Once you find the spot it’s fairly simple to repair yourself or have a professional fix for you.
If you lost no water in your main basin after letting it sit for 24 hours the next area to check is your Bio-Falls and your plumbing. Your Bio-Falls can be easily checked with a visual inspection both inside and out, being sure to check that your mechanical connections (screws etc) are all in good shape and there are no cracks in the body of the Bio-Falls. Your plumbing line can be checked several ways. One is by capping off all openings and doing an air pressure test on it…………you would need to have/purchase a pressure gauge, compressor and a few plugs. This will let you know if you have a leak, but without uncovering the entire section of buried plumbing you probably won’t be able to find it unless you have really good ears. The other option is to hook up some plumbing to your existing buried lines that will let you by-pass any streams and bogs. Usually this is hooked up inside your Bio-Falls at the head of your stream and laid down along the stream so that it will dump back into the main basin. By doing this you have essentially created a closed loop in your plumbing system. If after 24 hours your main basin water level has dropped, you probably have a leak in your plumbing. You have several options for finding the leak but it can be harder than other leaks. One option is to dig up your entire buried plumbing line and physically inspect it. A second option is to keep your system running for a few days and try to find a wet spot in the planting bed along the path of the buried line. Once you find one, dig in that area and look for the leak. If you find the leak you can usually fix the line by cutting the PVC and installing a coupler (works for pin-hole leaks) or splice in a new section of PVC if the line has actually cracked.
Once you’ve tested the plumbing and found it to be good, your next plan is to check the stream and waterfalls. Again this will require a bit more work and some extra equipment. The best way is to take some 2″ PVC and connect it to your existing pump. Lay the PVC part way up your stream and let it run for 24 hours. If there is no water loss, move it up stream a little further and repeat until you find a section that is losing water. Now you have narrowed down the search to a small section of the stream/waterfall. You may need to remove the stones in this section of the stream so as to isolate the actual hole. Once you find the hole (which is usually caused by a rodent) it’s fairly simple to patch the rubber liner. Go to your local supplier and ask for a patch kit….or call your installer.
REPAIR: With the location of water loss diagnosed you can repair it yourself, or hire a professional if it requires materials and equipment you don’t have on hand. But you have saved the repairman hours of diagnostic time, which means you’ve saved yourself many $$$$. Most leaks are usually easy enough to fix by: packing soil under a low spot of the liner; rearranging the rocks to prevent excessive splashing; cleaning the leaves out of the stream; or removing excessive amounts of plants in the biofalls (these will cause the water to spill out the back side of the filter). If it actually is a hole in the liner you can easily patch it with a liner repair kit available at most Landscape Supply centers that sell pond equipment. If it’s a plumbing problem your local hardware store might have what you need.