How to Find and Fix Leaks in Your Water Garden or Pond


Yesterday I was taking a walk in my backyard when I noticed that the water garden seemed to look a little parched and low on water. When I looked closer, I found that there seemed to be a leak because of which the water was draining. So, to make repairs, I did some research to understand how to find and fix leaks in the water garden- or pond.

So, how can one find and fix leaks in the water garden or pond? Leaks in the water garden or pond could be caused by evaporation, blockage in the flow, a leaking skimmer, or crack in the foundation or plumbing. Checking the liner are some ways to locate the leak. There are many ways to fix the leaks.

Some people may prefer to call in specialists and plumbers to find and fix leaks in their ponds or water gardens, but most of the times, such leaks can be identified at home and fixed quite easily. All it takes is timely and careful diagnosis of the kind of leak and location of the leak.  Supplies are most often available at the local market or online. There are many reasons why your water garden or pond could be leaking, but thankfully there are many fixes for the same as well.

Why is the pond or water garden leaking?

  • One of the most common causes for a suspected leak is evaporation, or rather; reduction in water volume in the pond or water garden, particularly when there is a fountain or waterfall installed in the same. What happens with these fixtures is that there is a lot of water movement and splashing of water from heights, which causes more evaporation than usual. Hence this might look like the pond or garden water is leaking, but it’s really just losing some water over time.
  • Sometimes, the pond liner or foundation of the pond, especially if it is concrete, can develop cracks or small tears along the way and this could be the reason behind the leakage. Leakage from the liner is less likely but over time, cracks in foundation have been noted as more common reasons for leaks. This type of leak can occur early on if the foundation was built using low-quality material, or later due to wear and tear.
  • Liner leaks, however, can be caused over time by holes or punctures created by interference and movement from tree roots planted too close to the pond. Sometimes people plant trees with heavier and larger root systems for aesthetic value, but these roots can damage the liner gradually and cause leaks.
  • Pond leaks are especially common when materials such as glass, wood and ceramic are used in the pond structure. While these materials look wonderful once finished and designed, they do wear down, crack and split faster than concrete, and can thus cause leaks in the water and pond basin.
  • Sometimes there may be leaks in the plumbing or pump, and it is difficult to tell if this is the case unless the pump is turned off for a period of long duration, like 24 hours or so. It is easy to mistake a pump leak as a pond or water garden leakage.
  • In case the pond foundation is made of soil or clay, chances of leakage increase since the material is more prone to getting eroded over time and with movement of water.

How to identify a leak in pond or water garden accurately

As noted above, leaks in water gardens and ponds can occur due to a variety of causes and factors. Sometimes there isn’t even a leakage, but loss of water and fall in water volume makes it look like there is. However, there are specific things one can look for when trying to identify if there has been a leak, and to diagnose the situation correctly.

  • A common occurrence is water spilling over the edge of the pond due to the pond liner having shifted lower and/or due to the water flow of a fountain or waterfall, if the latter fixtures are present. It is easy to check if this is the cause for the perceived water leak. What you have to do is simply fill the pond or garden to the water level you prefer and then glance over the edges of the pond to spot any possible spilling over. Potential spots for spillover to look out for are turns and the parts where the fountain or waterfall hits the water. Also be on the lookout for damp patches on the boundaries of the ponds, as water may be spilling over from there.
  • A good way to find out if you have a leak in the pond liner is by switching off the pump and waiting to see if the water level goes down. If it does indeed go down, you’ve found the leak. One thing to keep in mind is that the auto-fill valve should be turned off, as if that remains on, the purpose will be defeated and you won’t find the leak. Also do remember to keep the aerator running if you have fish in the pond, as they will need the circulation.
  • Once you have established that the leak is either in the liner or in the pond/garden foundation, you’ll need to find out the exact location of the crack or tear. To do this, you can use the milk method, in which you pour a small amount of milk or pond dye to the pond. Remember to do this only at the level the water level seems to have stopped reducing. The dye or milk will then swirl towards where the tear or leak is, and you can then start the fix.
  • In case of leakage in the plumbing, you will know that’s the case if the water level does not fall when the pump is off. At this point, it is a good idea to check all external equipment such as the pond filter, skimmer, etc and see if there are any tears or cracks in those. The fittings of the pipes may also cause leakage, so check for that and get a plumber to come in and fix them if needed.
  • A leak could be occurring if equipment had been installed incorrectly in the beginning. If the liner is attached to the filter incorrectly, this creates higher chances of leaks occurring as there is too much space for water to slip through. Similarly, the skimmer might be loose or some fittings, even as elementary as nuts and bolts, could have come undone. You will need to check for these small hindrances before taking any action.
  • Another way to identify leaks in the pond or water garden is to see what has been used to keep water at the desired level- is it a proper liner, or by any chance, has material like black foam been used? Black foam is not the appropriate thing to be used to prevent leaks as it would never be able to hold and retain the water, which would instead spill over and leak.
  • For liner leaks and leaks in skimmers, filters, aerators etc, concentrate your efforts by moving rocks, plants and other items around from near this equipment to check if the tear or hole causing the leak is located somewhere there. Check if there is any sedimentation, rock blockage or deposits that are clogging up the equipment and causing the leak.
  • Be sure to inspect the check valve, as a faulty check valve could easily lead to a leak in the pond. The reason for the leak may not entirely be the faulty check valve, but without repairing it, you will not be able to inspect for further signs of leakage in equipment.
  • Where a waterfall is concerned, much of the leakage could be due to the splashing of water. Observing the current placement of rocks in and around the waterfall is important for you to determine if the leak is being caused by splashing due to wrong positioning of the rocks.
  • Ensure that you cover all bases and check everything step by step. You must explore all possibilities keeping in mind the specifics of your pond or water garden as well as surrounding factors like the climate, activity of rodents, insects, fish in and around the pond, etc.

How to fix the leak once you’ve found it

So you found the source of the leak- great! Now you need to fix it. Sometimes this can be as easy as applying sealant and at other times, it may require a more complex solution. At times you may need professional assistance, but it’s always fun to try and come up with a fix by yourself for your little pond or garden. So here are some solutions to the different types of leaks-

  • In case of a tear in the pond liner that has caused the leak, you have two options- either you can fix the tear, if it is smaller than 5 inches, or if it is bigger, you’ll have to replace the liner itself. Many prefer to try and patch up large tears in the liner, but the sealant won’t work across a bigger area and your pond will face leakage again. There are plenty of pond sealants that are available online as well as in stores and can be easily used underwater. In order to fix the leak using this type of sealant, all you have to do is clean the surface of the liner properly, particularly the area of the tear, and then apply the sealant to the tear. Let it rest for about 24 hours, and since this sealant works underwater, the liner can go right back into the pond while the tear fixes.
  • If it is a matter of the liner having shifted that is causing leaks, the fix is very simple. All you need to do is adjusting the placement of rocks, plants and fixtures such as fountains and waterfalls so that the liner has enough space to fit and does not get pushed over the edge. In case of a waterfall, be sure to check both the left and right side for any possible leaks due to shifting. Try to place your hand behind the liner holding the waterfall, and check for dampness. Also consider looking for possible rodent or chipmunk activity such as tunnels dug by them behind the liner, which could cause a leak.
  • A common leaking issue is found with pond skimmers. If you have a mechanical pond skimmer, you’ll want to check if it is properly installed as per initial instruction, and if it is, then check that the connection is sealed completely and is watertight as it should be. Sometimes the skimmer gets displaced, and you can correct that by righting its position manually. If there is dirt or sediment in the skimmer, this could be causing the leak, and to fix that, you should clean the skimmer thoroughly and regularly. Otherwise, if there is a hole in the skimmer, you can apply putty that comes for this specific repair purpose to fix it. If the skimmer is about eight to ten years old, this issue is more common, and to fix it, you will need new screws and bolts to replace the hardware as well as new pond silicone. This should repair the leak.
  • Leaks in concrete or clay foundations of ponds are also common. These kinds of leaks cannot be worked through or fixed by applying putty since it won’t adhere to the material like it does to rubber and plastic. For cracks in concrete and clay, the leakage has to be stopped by filling in the cracks. For leaks in clay foundation ponds, sodium bentonite is a good choice to seal the crack and lock in, thus fixing the leak. Further, bentonite is easy to apply and just about anyone can use it for clay pond repair. The best thing about this solution is that even if you can’t locate the exact spot of the leak or can’t reach it easily, you can put some bentonite on the water surface and it will gradually reach the crack and fill it in. Many variants of sealant solutions are available for concrete pond foundations as well. These can simply be brushed on to the area of the leak after that part of the pond is emptied, or you can also clear out the whole pond, drain it and then paint the solution all over the dry basin for future protection against leaks.
  • If you find that the pond bottom is leaking, but you cannot really pinpoint the source, you can always take the help of dispersants, which are basically chemical solutions that’ll plug the holes and gaps in your pond bottom with clay and will thus be successful in fixing the leak. A good example of an efficient product that does this task well is Water$ave by Polymere, which follows the principle of using granulated particles that then turn into sealant to plug in holes in the pond and fix leaks.
  • In some cases, though this is less common, the source of leakage of the pond or water garden is from the drainpipe, which may have been installed poorly or may have degraded over time. Sometimes, if the water is hard or corrosive in nature, the drain pipe as well as the outlet pipe may rust over and get damaged, causing leakage. Mostly in such cases, you can replace the drainpipe for a more long-lasting solution.
  • You can also use patches and adhesive sealing tapes to fix leaks that occur in the pond liner or foundation, provided the crack or tear is not too big. Tape is not the most attractive or long-lasting solution, but it certainly is a quick fix when you need to repair the leak for the interim. There are a few varieties of sealing tape that are more long lasting though, and you can choose those for small leaks.
  • Something to always keep in mind when fixing or attempting to fix leaks in ponds and water gardens is that the plants and fish present in them should be safe during the process. When chemical additives are being put in the water, it is a good practice to take out the plants beforehand, temporarily repot them, and transfer any fish from the pond/garden to safe containers. In fact, when the first signs of leakage are observed, you may want to start making arrangements for the transfer of the plants and fish right away to avoid dangerous consequences.

Tips to safeguard against leakage

It is often said that prevention is better than cure, and the same is true for leakage in water gardens and ponds. While it is not often difficult to find the source of the leak and repair it, it would definitely spare you time, money and valuable effort if your pond were already safeguarded against leakage and thus the chances of an actual leak occurring were low. That said, no preventive action can actually guarantee that over time, a leak will not develop either in the pond lining/foundation or the equipment. But it still pays to be careful and keep certain things in mind to reduce the risk of leakage.

  • Be sure to clean the pond/garden equipment on the regular using proper cleaning methods and supplies. The key to cleaning filters, aerators, skimmers and so on is to take them out of the water, rinse or wipe them down well to remove all grime and sediments, and let them air dry for a few hours before putting them back in place. This way you can keep an eye on the condition of the equipment, prevent blockage in their paths and detect tears or holes swiftly, thus avoiding leaks.
  • Know the difference between the kinds of sealant and putty, and understand what can be applied where before actually using it. Find out about the exact composition of your pond’s bottom and structural material if you were not involved in the construction process, and proceed accordingly. Also be precautious about using too much chemical in the pond for either preventive measures or to fix actual leaks, as excess bentonite, and even other substances such as gypsum, can upset the pH balance and nutrient content of the water.
  • It is a good idea to be a part of the building process of the pond or garden. That way you can monitor the process and ensure that low quality material is avoided. Stone and concrete are good ideas for ponds while clay is often a preferred base for water gardens, but always remember that a good vinyl liner should be used and positioned properly to protect from spilling over and leakage. In order to add extra protection for the liner and protect it from tearing before time, ensure that the edge has a little overhang to it. Ensure that the equipment such as pond filter, skimmer are installed properly and check the functioning before finishing up.
  • It is important to try and protect the pond liner as much as possible, apart from having a leak-proof pond bottom. It is suggested that for best efficacy and maximum safeguarding, liners should be surrounded with minimum of nine inches soil, to avoid tearing and imminent leakage. When you are picking the pond liner, be sure to choose the kind that’ll best suit your needs. If you are envisioning your pond or water garden to have a few turns and not a simple square or round shape so to speak, choose an EPDM rubber liner for flexibility. If you want rigidity, pick a PVC liner. Choosing the right liner can make all the difference when it comes to chances of over spilling and leaking.
  • Do consider having an auto-fill valve which works along with your pond skimmer, to keep water levels high. Particularly in drier and hotter weather, water tends to evaporate faster, and while this isn’t exactly a leak, it is still loss of water and can be minimized. Auto-fill valves are easy to install, affordable and are perfect options for smaller, home-grown ponds and water gardens. All you have to do is connect your garden hose to it and the valve will take the water it needs to add to the pond.

Recommendations for fixing solutions

While sealants of all varieties are easily available in the market and online, one could still use a guide to help in picking the optimal option based on requirements and budget as well as the type of leak, especially if it’s the first time fixing a leak. Here are a few products you can consider buying to fix leaks in your pond or water garden-

  • Liquid Rubber Waterproof Sealant- This particular sealant is perfect for concrete pond bottoms and is available in different quantities, so you can pick according to how much sealing you actually need to do. For the quantity, this sealant is fairly affordable and is also water-based, free from toxic odor and takes about a day or at most, two days in more humid climate to cure the leak. Like all concrete crack/leak solutions, this solvent must be applied to a dry surface, so be sure to drain the pond before using this. This product also comes in various colors if you prefer to match the seal with your pool, so that’s great. Buy it here at amazon here.
  • Gorilla 4612502 Waterproof Patch and Seal Tape- If you have a dry surface to fix, this patch tape can work very well, provided that you don’t mind the low aesthetic appeal and have no plans to take it out later. This tape is lightweight and sticks really well to the surface, sealing in the crack in your pond and keeping it in. It also works effectively at sealing and fixing pond liners as long as the surface is kept dry. After the tape has adhered to the surface, it won’t come off even with contact to water, making it a good solution for water gardens and ponds. The only issue is that removing this is very hard, so don’t go for it if you mind that. Buy it at amazon here.

Related Questions

How can one protect the fish pond/water garden from predators, rodents etc?

The pond and its habitant fish can be protected from rats by avoiding leaving fish food lying around, from herons, cormorants and ducks by covering the pond with netting, and from insects such as dragonflies by filtering the pond well.

Is there any way to check on the water level in ponds/ water gardens without having to put in manual effort?

These days one can use water control systems that operate electronically. There is a control box supervising the water level and a sensor that alerts you of changes in water level and the valve, connected to your mains, will add water as required to the pond. This is good for long-run investment.

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