A pump may be deprived of water even when there is still water in the pond. A low level at its intake or a blockage upstream can interrupt the flow it needs. Noise, weak output, or a damaged-looking component is a reason to investigate, not proof by itself that the pump ran dry. Use the instructions for your exact pump when inspecting or restarting it.
First, check the water reaching the pump
Look at the water level where the pump actually draws water: the pond, skimmer, intake bay, or waterfall vault, depending on your setup. A pond can appear full while the pump's own chamber is low. Check whether a skimmer basket, filter mat, pump cage, or intake has collected leaves and debris that restrict the route to the pump. Do not reach into a running pump or electrical equipment; switch it off and follow the manufacturer's safe-service directions before handling components.
What signs call for a closer inspection?
Gurgling, unusual noise, or reduced flow may signal that the pump is not getting enough water. Address the water level or obstruction rather than waiting for the noise to continue. The source describes scratches or dark marks on rotors, changes to bearings or ceramic shafts, and a distorted pump body in examples from certain AquaSurge, SLD, and AquaForce pumps. Those photos and component signs are model-specific examples. They do not establish the cause of a problem in another pump, and a visible mark may have more than one explanation.
What should you do next?
After switching off the unit as its instructions require, document the water level, intake condition, noise, and any visible damage. Clear routine debris only in the manner approved for your equipment. If parts appear warped or the pump will not run normally after the water-supply issue is resolved, consult the manual or a qualified service professional for that exact model. Do not assume that replacing an impeller, bearing, or shaft will solve a problem without checking compatibility and the underlying cause.
Reduce the chance of another low-flow event
Monitor water at the pump's intake, especially during evaporation or heavy debris seasons. Empty skimmer baskets and maintain filter mats and protective cages in line with their instructions. If maintaining the water level is a recurring problem, investigate why before selecting an automatic-fill solution. For broader pond upkeep, see Fall Pond Cleanup: Managing Leaves and Debris; if your concern is overall pond circulation, see Does Your Pond Need a Koi Pond Aeration System?.
The most useful conclusion comes from checking the water path and the actual pump model, not from one sound or photograph. Restore a clear, adequate supply of water according to the pump's instructions, and have unexplained wear or persistent poor performance assessed before putting the unit back into routine service.