How to Stop Leakage From a Fish Pond

Updated November 21, 2016

Fish ponds bring life and interest to any outdoor setting. Regular maintenance will keep your pond in its best condition. However, even the most well-maintained pond can develop leaks over time. Leaks can be caused by normal wear and tear, poor pond construction or even faulty pipes. Finding the source of the leak is often more time-consuming than the actual repair.

Look around the pond for any obvious wet spots. Use a soil probe or a ditch shovel to check for moisture beneath the soil in suspected areas.

Inspect the pipes around your pond, such as the drainage and outlet pipes, as these are often sources of leaks. This is especially true for older ponds.

Turn off your pump to stop circulating water in the pond. Allow the water level to drop on its own until it stabilises. When the water stops dropping, the leak should be somewhere at that water level. Inspect the area to find the leak.

Prepare holding tanks for your fish by filling containers with water from the pond. Catch the fish in a net and place them into the holding tanks until your repair work is complete.

Drain the remaining water from the pond, marking or making a note of the location of the leak.

Repair the leak with the proper repairing materials and tools for your specific type of pond. There are repair kits available for rubber and PVC pond liners. Cement ponds may be sealed with a fibreglass resin or pond sealant. Spray sealants seal leaks in stone waterfalls. These products are also available in pond supply stores. When using patches or sealants, be sure to follow the instructions on the label of the product exactly. For natural or unlined ponds, work bentonite clay, which expands when wet, into the walls and floor of the pond to seal the leak. Ask a pond specialist to recommend the appropriate amount of bentonite for your specific pond.

Allow the patch or sealing product to dry thoroughly. Refill the pond with fresh water. Treat the water with the usual chemicals or treatments you use for water and fish safety.

Bring or allow the water to naturally reach the appropriate temperature. Place your fish in plastic bags or buckets full of holding tank water and set the bags or buckets in the pond for 20 minutes. This allows the fish to acclimate to the water temperature and reduces shock.


If your pond empties itself all the way when you are trying to locating the leak, there may be a leak in the bottom drain piping system. It could be difficult and costly to repair. This work should be done by professionals. If the water level of your pond begins to drop too low for your fish, complete Step 1 of Section 2 to ensure their safety. Replace any rubber and PVC liners that can't be patched.

Things You'll Need

  • Soil probe or ditch shovel
  • Holding containers
  • Fish net
  • Liner repair kit/sealant/bentonite clay
  • Water treatments
  • Plastic bags or buckets
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