Instructions
Fill the pond. Then watch the water level for a day or so. If the water never goes below a certain level, the leak may be in the upper part of the liner. Run your hand along the top wall of the pond to feel for leaks as well as visually inspect it.
Check the area around the pond. Make sure the rocks, plants and other decorative items aren't misplaced. This can cause the water to run outside of the pond. Reset the decorations and see if this fixes the leak in your koi pond.
Feel the ground around the koi pond for excessive moisture. This can help you locate the general area of any leaks.
Inspect all the plumbing. Feel the joints and connectors to see if they are wet. If they are, the problem is in the pipes and not the pond. Make the necessary repairs.
Pull enough water from the pond into a container to support your fish for a short period of time. Remove the fish. Visually inspect the pond with the new, lower water level. Feel for leaks as well. Make sure the liner hasn't slipped from its original position.
Put more water back into the pool. Do not return the fish at this time. Pour a small amount of milk into the water. The cloudiness of the milk as it seeps toward the leak should help you find the hole in the koi pond.
Fix the leak with repair cement appropriate for your koi pond's liner. Refill the pond and replace the fish.
How to Troubleshoot Koi Pond Leaks
All koi ponds lose some water to natural causes such as evaporation and wind splash. However if your koi pond is losing water at a faster rate than you think it should, here are some tips you can use to help troubleshoot the leaks.