Is it evaporation
A normal pond loses an inch or so a week in hot dry weather. A bigger loss, or loss in cool weather, suggests a leak. Use the bucket test: fill a bucket, mark the level and set it in the pond. Compare after a few days.
Turn off the waterfall
If the level stops dropping when the waterfall is off, the leak is in the waterfall or its plumbing. Run it again and watch the edges for wet spots.
Turn off the pump
If the pond still drops with the pump off, the leak may be in the liner or the skimmer. If it stops, the leak is in the plumbing.
Watch the level
Let the level drop and see where it stops. It will usually stop at the height of the leak. Mark it and inspect that area.
Common causes
Low spots in the edge, liner folded down by settling, skimmer seals, plumbing joints and plant roots are the usual causes.
When to call
If you cannot find the leak after these tests, or if the liner needs to be lifted, call a professional. We find leaks every season.
Do the bucket test, then turn things off one at a time.
