How To Find A Leak In A Koi Pond

First steps - Determine if the leak only happens when the pump is turned on.

The first step in discovering a leak in your pond is determining if the pond only loses water with the pond pump on or off. Use a yard stick take a measurement of the water level and recheck it again every 24 hours, at the same time of day if possible, for three days. If your pond is losing water quickly, turn off the main pond pump and continue to measure. If the water level continues to drop then you know the problem is in the main pond liner. If this is the case keep measuring until a stopping point is reached, then look around the complete inside perimeter of the pond where the water level has leveled off for a hole in the liner or low edge. You may need to refill the pond again with an inch or two of water to confirm the area at which the pond stops leaking.

While you are taking the measurements, an inexpensive Aquascape pond air pump can be used while your main pump is shut off. This will keep your fish healthy as you take time to discover the leak. Cold pond water holds more dissolved oxygen, so during colder months of the year it's a perfect time to trouble shoot pond leaks. If you need a professionals help in finding the leak, you can save money by having the problem narrowed down before a Certified Aquascape Contractor comes out to your pond. Below is a list of areas that your pond leak could be coming from. Pond leaks are easiest to find on warm days with dry ground around the pond.

Most common - Leaks in streams

Having a leak in the waterfalls or streams is one of the most common areas that a leak will develop. With your pond running on a dry day, brush back any mulch or small gravel on the outside edge pond liner along the stream. Look for wet areas or a small trail of water. If a wet area is found find its source by pulling back more of the mulch or rocks upstream to find the point where the water is coming out. In most cases, once this area is discovered it can be easily fixed by adjusting the rocks and pond liner. Typically, you can just lift the liner up to create a slightly larger berm to retain the water, and then put some fill dirt or a rock underneath the liner to hold the new position.

Other situations that may cause leaks in a stream include: string algae, leaf debris and pine needle build up which can divert water out the sides of the stream liner. Simply remove this debris and then recheck your water level again over a 24 hour period to see if the problem has been resolved. Also, make sure there is a clear path for your water to flow down the stream without being obstructed in too many areas. Remove some large rocks from the center of the stream if needed.

If you are still having trouble finding the leak in the stream you can use temporary tubing from your main pond pump and run it over to the beginning of the stream above the ground. You would then check the water level after 24 hours. If the pond and stream are still leaking, move the temporary outflow pipe further down the stream in small increments. Keep on moving the new outflow water pipe down the stream until the stream section with the leak is discovered. Once this area is identified, remove as many rocks as needed from that section of stream to discover the hole in the pond liner or other problem.

Leaks in Pond Equipment

The thin walls of kink free tubing can often become stiff and brittle with age, which could lead to multiple small cracks or holes. Other styles of kink free tubing can spring many pinhole leaks all over from the water pressure from the pump. In some situations, the piping section with the leaks could just be cut out and then you can reattach the new ends using barbed fittings and hose clamps. Flexible PVC pond piping or hard PVC plastic pipe is the best long term option because of its durability. You should replace kink free tubing with flex PVC pond piping when possible.

External filters (Canister Filters, UV's, bead filters and external pumps)

Check for leaks around PVC connection fittings, barbed tubing connections, clamps, O-rings, and gaskets. Check around base of filter for water and check plastic filter housing for cracks. The area around the external pond filter may be damp or wet depending on the severity of the leak. Cracks in pond filter connections can be caused by seasonal weather changes, long term exposure to the sun and age of equipment.

Waterfall Filters

Sometimes pond leaks can develop when the water is too high in the waterfall filter box. This situation occurs when the water inside the box rises too high and flows out the sides or back rather than out the front. Some common problems that would cause this include a filter box that is not level, leaning away from the stream, or a slate rock piece that is too thick sitting on the lip of the waterfall filter causing the water to rise up too high in the waterfall filter. If you think this might be the problem, remove the waterfall slate piece entirely from the lip of the filter. Then run your pond for the 24 hour leak check. If the leak has stopped, use waterfall foam to install a new thinner slate piece or leave the piece off altogether. Another area to check at the waterfall filter is the pond liner and filter faceplate connection. Insure that the screws and silicone holding the liner to the filter faceplate are in good condition and still in place.

Skimmer Filters

Skimmer filters are mounted to the pond liner to make a water tight seal with screws and silicone. In some skimmer filters, after they have been in the ground several years, the screws rust out which no longer holds the pond skimmer faceplate tightly in place causing a leak. You can check the screws by simply looking at them to see if they are all intact or rusty. The screws along the sides and bottom are likely to be in the worst condition. If they are missing or rusted out they should be replaced along with the bead of silicone around the faceplate. In some instances, not enough silicone was originally used during the installation of the pond skimmer filter which could also lead to a leak from that area. With the pond pump off looking for leaks, if the water level stops going down right at the bottom of the skimmer box opening this might be the problem area. If the water level in your pond stops leaking at the bottom of any bulkhead fittings that you might have in your skimmer filter, check to make sure they are tightly connected.

Holes in Pond Liner

When it comes to pond leaks a natural conclusion to draw is that there is a hole in the liner, this actually is not very typical at all. Pond leaks are usually from some of the other areas mentioned above. Holes are very difficult to find by draining the water out of a pond, this technique is not recommended. Use the measuring method mentioned above and let the pond water level drop, once it stops going down you will know that the hole is somewhere at that level. Animals are likely culprits. Holes from animals such as chipmunks, moles, ants, and mice are more likely to occur within the first foot of depth of your pond. Animals like to make homes in large void spaces between larger rocks in your pond, stream and waterfalls. Make sure these areas are filled with dirt, small gravel or a small amount of cement if needed. Holes in pond liners can also be caused by plant roots. If you discover a hole in the liner, be sure to patch it correctly using proper technique. This includes cleaning the area to remove algae and dirt, brushing on a product called quick prime plus and then properly pressing on a liner patch. 45 mil EPDM pond liners are the standard in the industry. Thin, inexpensive plastic liner is more prone to developing holes.

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