I’ve been experiencing a drop in the water level of my pond over the past few weeks. How can I find out if my pond is leaking? What can cause a pond to leak, and how can I fix the problem?
Unfortunately, leaks are an eventuality waiting to happen in and around a koi pond. Identifying and repairing them can be a thankless task, especially if there is no leak to be found – Yes, phantom leaks do exist!
Wherever I’ve worked in the industry, from a retail assistant, being sent out to a customer’s pond to find and mend a punctured liner, through to a koi farmer sealing old land drains that threaten to empty a mud stock pond – leaks have always been a reality, and unfortunately will continue to be so.
From your letter, you have identified a loss of water from your pond. Your next step is to identify where the leak is and fix it.
Locating the leak
1. Do nothing. This is the easy bit. Let gravity and water take their course and see where the dropping water level finally rests. This marks the level where you’ll have to inspect around your pond’s perimeter. Hopefully it will be in the top quarter of your pond and that there won’t be any further leaks above it. Algae and other detritus are likely to have covered your liner, so you’ll have to clear this to get a good close look. How easy this will be (as well as its repair) will depend on how your pond has been constructed. Liner (PVC/Butyl)
The smooth nature of a liner means that a hole should be relatively easy to find, but care must be taken to examine under folds and creases. Close inspection of the liner should also give you an idea as to the condition of the liner as a whole (some may become brittle with age) and allow you to decide whether it is worth mending, or whether a new liner (with a lengthy lifetime guarantee) may be the better option. A repair will either involve a patch/glue or a strip of pliable adhesive tape.
Concrete
Holes in a concrete pond can be very difficult to locate as the porous appearance of the material can mask even the smallest of holes. More often than not a reapplication of waterproofing sealant or re-render is required. Either way it is likely to involve putting you pond into ‘dry dock’ and finding your fish some temporary, quality alternative accommodation (often a tough task in itself).
Fibreglass Coated Blockwork
Locating holes in this can be just as difficult as finding them in concrete, depending on the quality and thickness of the resin used in its finishing top coat. A reapplication of resin may solve the leak, but requires excellent preparation of the old surface and as with concrete, will more than likely mean draining the pond completely.
Phantom leaks – when a loss of water is not caused by a leaking liner.
1. Waterfalls
A waterfall is always my prime suspect when looking for a leak. Turn it off for a few days to see if it’s the cause. When constructing a pond, waterfalls can be one of the most difficult features to perfect. Not only must they complement the character and size of the pond, they also have to be watertight. The most straightforward way of ensuring that all of the water that feeds a waterfall runs into the pond is to build the waterfall and pond from the same piece of liner. In this way, if the stepped rockwork of a waterfall were to settle, crack and spring a leak then any leaking water will still return into the pond if only out of sight and under the construction. If it leaks, then a reapplication of a liquid plastic sealant or a re-build may be required.
Waterfalls can also lose water by splashing drops of water beyond the watercourse. What may seem to be an insignificant drip can soon add up to a loss of several gallons causing the water level to drop. A few well placed rocks or a reduction in flow rate can soon prove effective.
2. Bog areas and sunken rockwork.
Submerged marginal planted areas or partially submerged rock work can act as blotting paper, drawing water out of the pond and into the surrounding soil, cement or lawned area. These problems usually manifest themselves just after a pond has been constructed. The rate of ‘blotting’ will also increase with temperature, being at its most extreme in the summer months. There is little that can be done to prevent water rising by capillary action but it is useful to be able to associate such a drop in water level with capillary action rather than a leak.
1. Leaking pipework.
Where filters are external to the pond and above the water level, tiny hairline splits in hose or perished washers in hose unions can all be common causes of losing water.
If possible, inspect the soil along the run of the pipe and at best inspect all hoses and pipework at first hand. Try to isolate leaking pipes from the other possible causes of a dropping water level by running the pond without the filter over night to see if this has any adverse effect on the water level.
Causes and solutions
Leaking waterfall: If made from natural stone, try coating the waterfall with a clear liquid plastic sealant. If you know it has been constructed without a liner underlay, your best option is to rebuild it.
Leaking liner. Allow gravity to expose the lowest leak and repair using a patch – similar to repairing a punctured inner tube.
Splashes. Study waterfalls and fountains closely to ensure that every drop of water is returning back into the pond. Adjust water flows where necessary.
Leaking pipework. Check all exposed pipework and look for ‘damp areas’ where pipework is buried.
Bog areas. If a bog area has been constructed to allow water to be drawn into soil that is adjacent to the pond, then water will be lost out of the pond. Ensure the liner acts as an impermeable barrier between the soil in a bog area and any adjacent garden soil.
I’ve been experiencing a drop in the water level of my pond over the past few weeks. How can I find out if my pond is leaking? What can cause a pond to leak, and how can I fix the problem?
Unfortunately, leaks are an eventuality waiting to happen in and around a koi pond. Identifying and repairing them can be a thankless task, especially if there is no leak to be found – Yes, phantom leaks do exist!
Wherever I’ve worked in the industry, from a retail assistant, being sent out to a customer’s pond to find and mend a punctured liner, through to a koi farmer sealing old land drains that threaten to empty a mud stock pond – leaks have always been a reality, and unfortunately will continue to be so.
From your letter, you have identified a loss of water from your pond. Your next step is to identify where the leak is and fix it.
Locating the leak
1. Do nothing. This is the easy bit. Let gravity and water take their course and see where the dropping water level finally rests. This marks the level where you’ll have to inspect around your pond’s perimeter. Hopefully it will be in the top quarter of your pond and that there won’t be any further leaks above it. Algae and other detritus are likely to have covered your liner, so you’ll have to clear this to get a good close look. How easy this will be (as well as its repair) will depend on how your pond has been constructed. Liner (PVC/Butyl)
The smooth nature of a liner means that a hole should be relatively easy to find, but care must be taken to examine under folds and creases. Close inspection of the liner should also give you an idea as to the condition of the liner as a whole (some may become brittle with age) and allow you to decide whether it is worth mending, or whether a new liner (with a lengthy lifetime guarantee) may be the better option. A repair will either involve a patch/glue or a strip of pliable adhesive tape.
Concrete
Holes in a concrete pond can be very difficult to locate as the porous appearance of the material can mask even the smallest of holes. More often than not a reapplication of waterproofing sealant or re-render is required. Either way it is likely to involve putting you pond into ‘dry dock’ and finding your fish some temporary, quality alternative accommodation (often a tough task in itself).
Fibreglass Coated Blockwork
Locating holes in this can be just as difficult as finding them in concrete, depending on the quality and thickness of the resin used in its finishing top coat. A reapplication of resin may solve the leak, but requires excellent preparation of the old surface and as with concrete, will more than likely mean draining the pond completely.
Phantom leaks – when a loss of water is not caused by a leaking liner.
1. Waterfalls
A waterfall is always my prime suspect when looking for a leak. Turn it off for a few days to see if it’s the cause. When constructing a pond, waterfalls can be one of the most difficult features to perfect. Not only must they complement the character and size of the pond, they also have to be watertight. The most straightforward way of ensuring that all of the water that feeds a waterfall runs into the pond is to build the waterfall and pond from the same piece of liner. In this way, if the stepped rockwork of a waterfall were to settle, crack and spring a leak then any leaking water will still return into the pond if only out of sight and under the construction. If it leaks, then a reapplication of a liquid plastic sealant or a re-build may be required.
Waterfalls can also lose water by splashing drops of water beyond the watercourse. What may seem to be an insignificant drip can soon add up to a loss of several gallons causing the water level to drop. A few well placed rocks or a reduction in flow rate can soon prove effective.
2. Bog areas and sunken rockwork.
Submerged marginal planted areas or partially submerged rock work can act as blotting paper, drawing water out of the pond and into the surrounding soil, cement or lawned area. These problems usually manifest themselves just after a pond has been constructed. The rate of ‘blotting’ will also increase with temperature, being at its most extreme in the summer months. There is little that can be done to prevent water rising by capillary action but it is useful to be able to associate such a drop in water level with capillary action rather than a leak.
1. Leaking pipework.
Where filters are external to the pond and above the water level, tiny hairline splits in hose or perished washers in hose unions can all be common causes of losing water.
If possible, inspect the soil along the run of the pipe and at best inspect all hoses and pipework at first hand. Try to isolate leaking pipes from the other possible causes of a dropping water level by running the pond without the filter over night to see if this has any adverse effect on the water level.
Causes and solutions
Leaking waterfall: If made from natural stone, try coating the waterfall with a clear liquid plastic sealant. If you know it has been constructed without a liner underlay, your best option is to rebuild it.
Leaking liner. Allow gravity to expose the lowest leak and repair using a patch – similar to repairing a punctured inner tube.
Splashes. Study waterfalls and fountains closely to ensure that every drop of water is returning back into the pond. Adjust water flows where necessary.
Leaking pipework. Check all exposed pipework and look for ‘damp areas’ where pipework is buried.
Bog areas. If a bog area has been constructed to allow water to be drawn into soil that is adjacent to the pond, then water will be lost out of the pond. Ensure the liner acts as an impermeable barrier between the soil in a bog area and any adjacent garden soil.
