Finding A Leak
Uh oh - so you think your pond has a leak. The good news is that most water gardens built today are constructed with EPDM liner - a durable, long lasting waterproof membrane that is easily patched. However even owners of concrete ponds can use this simple diagnostic to determine the location and the cause of their water loss.
The first step in addressing a leak in a water feature is to be certain that you have a leak. Evaporation during hot, dry, windy periods can account for nearly 4 inches of drop in water level in a week. Even more water loss can be attributed to wind blowing water outside the containment area.
If your loss is dramatic and you are certain that water is escaping in other ways, examine the following areas:
Wicking & Capillary action
Water can be drawn from a water feature through wicking. An excessive number of plants that have roots outside of the containment area that protrude into the pond will draw water out of the water feature. Remove these plants from the border of the pond or trim them so they do not dip into the water.
Simply having a layer of dirt that extends into the pond will cause water loss through capillary action. If you notice visible wet spots in the dirt, you are losing water at a rate than can be extensive. Remove the dirt from the edges.
Waterfalls with liners cut too close to the falls may suffer tremendous water loss without any signs of wet grounds nearby. The waterfall should be checked for splatter and the liner around the falls should
extend out and angle upwards to insure that any water that does spray out will eventually work it's way back into the pool.
Many times during construction, the liner will need to be folded and tucked. If water runs near these folds, back pressure will force water through the folds, many times even uphill. Unfortunatly, these are the most
difficult to locate since the water does not appear until after it leaves the liner area. The best way to defeat these is to raise the liner in that area by
stuffing dirt, bricks or any solid material under the liner. These can easily be avoided during construction by making sure that the liner is folded away from the flow
of the water and that the area surrounding the stream angles towards the pond sufficiently.
Often leaks occur in the circulatory system rather than the general water containment area. Normally, water is circulated outside of the main containment area and returns through a waterfall or spitter. To determine if this is the source of the leak, fill the water feature and turn off the circulatory system (pump). Then note if the water level drops excessively. If the water level drops without the pump being on the problem most likely lies elsewhere.
Next, turn the pump back on and closely examine the water return (waterfall or spitter). Is the water going over the edge of the waterfall rather than returning to the pond? If so, restructure the waterfall area. Splashing can account for water loss too - the general pondbuilder's rule of thumb: for every 1 foot of waterfall drop extend pond liner 1½’ from the point of impact.
If you are certain all of the water is returning to the water feature from the waterfall or spitter, the leak must be in the plumbing somewhere. You may have underground tubing with couplings, valves, or elbows that are no longer watertight. Replace defective plumbing.
If your liner sits directly on the ground without a solid underlayment of concrete or hard clay, the weight of rocks on the perimeter of the pond may promote settling of the ground and
leakage of water. To avoid this, make sure there is sufficient clearance above the water level and that the sides of the pond are not too steep. We recommend a 45° angle around the
If the water level in the pond drops without the circulation running, the leak must be within the main portion of the water feature. Continue to let the water level drop until it stops dropping. If you have fish you will need to monitor the water level and be prepared move them to another area if the leak is in the very bottom. The water level will stop dropping at the level of the leak. Obviously some loss will continue to occur with evaporation, but you should be able to notice the difference between water loss from evaporation and that from a leak.
When the water level stops descending, examine the liner and any penetrations in the water containment media, such as bulkhead fittings, skimmers or drains that are at the approximate level of the water. Fix any problems that are found.
Ponds and Falls, llc.
12 Heaton St. Rochester, NH 03867
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