A low edge is a place where the pond or stream liner has settled below the water's path, allowing water to escape into surrounding ground. It is one possible cause of water loss, not a diagnosis for every pond that needs topping off. Start with Is My Pond Losing Water to Evaporation or a Leak? if you have not yet checked the broader pattern.
Look for clues along the edge
Walk around the pond and any connected stream while the feature operates normally. Note unusually damp ground, water pooling outside the liner, or a spot where water appears to pass over the edge. Compare the liner's position with the operating water level, including areas concealed by rocks or plants. Do not pull apart a stable edge or dig near buried wiring or plumbing just to test a guess.
Confirm where water is escaping
A wet spot may come from splash, overflow, a pipe connection, or runoff rather than a low liner edge. Mark the suspected location and watch whether it becomes wet while the pump runs. Take photos of the waterline and record the water level over time. If inspection requires reaching near a pump or electrical equipment, switch off power first and follow the equipment instructions.
What does a repair involve?
Where a low edge is confirmed, the liner needs to be supported above the feature's operating water level with sufficient overlap and stable backing. The safe method depends on the liner, edging, soil, rocks, and nearby plumbing. A small adjustment may be straightforward for an accessible, simple edge; a buried or heavily loaded edge is better assessed by a qualified pond professional. Do not cut the liner or rely on sealant to correct an edge that is physically too low.
Check the result
Once a repair is made, restore the edging without pinching or puncturing the liner, run the feature as instructed, and monitor the water level and surrounding ground for several days. If water still escapes, keep looking for another cause rather than repeatedly raising one area. Rapid water loss or water near a building calls for professional help.