When your pond has a leak, the first thing to do is walk around the perimeter, barefooted.  If you find no wet spots, then check around your waterfall.  Quite often the stones in the waterfall will move ever-so-slightly, just enough to change the course of the water.  If there doesn’t seem to be any additional water going over-board by the waterfall, look beneath the waterfall, where it attaches to the pond.  If there is no actual seal, it could be sucking the water out.

BUT… Watch the weather!  Hot days and windy days both increase evaporation exponentially.  It is surprising how quickly the water evaporates and you can quickly decide there is a leak where there is none.  BUT… If all else fails and the water is still getting lower, while you are dumping more water into the pond but not keeping up with it, try this:

Let the water go down.  Not all the way to the bottom, of course, but let it keep dropping.  Where it stops, you should be able to find the leak…and fix it.  Did you ever have a Water Bed?  The same 2-sided patch will work on your pond.

WHY IN THE WORLD would your pond spring a leak??

  1. Tree or grass roots, in some cases, are able to penetrate the liner (especially Weeping Willows or Bamboo).
  2. Vermin! They have been known to dig under a pond, and, while nesting, chew into the liner.
  3. Big footed people? Walking in the pond, usually on small rocks.  The 45EPDM liner is good for 20 years and that says they will eventually break down.  Lots of people think that adding rocks on top of the liner will add to the life of it.  But walking on the rocks, pressing them into the liner, can’t be a way to save it.

Good luck!  If your pond/liner is 20 years old, it is better to replace it than patch it if you love your fish.