Pond Pump Troubleshooting Guide

Is your pond pump running slow or not working at all? It can be quite concerning when your pond pump stops working, however, most issues are easy to fix without compromising the quality of your pond water or the health of your fish. 

First, make sure your pump is receiving enough water. Many pumps are submersible and are required to be immersed completely in pond water. While this may seem obvious to some, there have been many cases in which unusual sounds, overheating and shut-off have been due to a submersible pump not getting enough water. This will not be a problem if you have an external pump.

Power Supply 

If your pump does not have any power when you switch it on, switch it back off and look for damages to the cord. Tears in the electrical wiring will require a new unit, as exposed electrics can be extremely dangerous. Replacing the entire water pump will be safer and much simpler than replacing the cord alone. If the cord is fully intact and the unit is not running, check the main circuit breaker.

If there are no rips in the electric wiring and the pump still does not have any power, take the pump out of your pond and turn the unit on. Do not let a submersible pond pump run for long, as submersible pumps need to be kept in water, but check to make sure the motor is working and listen for any unfamiliar noises. If the motor is not working, you may need to replace the entire unit.

*Be extremely cautious when handing pond electrics. We do not recommend handling a pond pump with wire damages. This behaviour can lead to electric shock and severe damage to one’s health. Please ensure that a qualified electrician is consulted to run these pump checks.*


If your submersible pump is not fully submerged the unit will run dry, this will lead to the unit getting very hot and overheating. To prevent this, simply ensure that you submerge the unit fully in water.

If you notice your pump getting extremely hot, unplug the unit and submerge it in very cold water for 20-30 minutes. This is plenty of time for the pump to cool off. When you place the pump back in the pond water, plug it in and it should work just fine. 

Water Pump Blockage/Impeller Damage 

Another issue that pond keepers can experience is diminished flow rate / non-existent flow rate. If there does not seem to be as much water flowing from your pump as there used to, or no flow at all, there is probably something that occurred inside the unit that can be repaired. Here are some reasons your pump may be experiencing flow rate problems:

Check the pump inlet and outlet for any obstructions. If this is the cause of slow moving water, remove the debris then check the pump o-rings for damages. If the o-rings, which seal the pump, are damaged, this could be why the debris was able to get inside your pond pump. O-rings are easy to replace and you can find them on our spare parts page.

If there are no visible obstructions, open up, and inspect the inside of the pump. Check to make sure your impeller is not broken or being trapped by any particles.

Water pumps are made to handle small particles, but these particles will build up and can affect the parts inside the pump. If the impeller it is not broken and just stuck by waste in the pump, get rid of the waste and put the pump back together. A broken impeller will spin a full 360° - it should only turn 180°. If your impeller is spinning all the way around, replacement pond pump impellers can be found in our pond pump replacement parts section.

If the impeller is not spinning at all, make sure the unit is turned off and try manually spinning it with a tool, such as a screwdriver or a pen. If you are unable to manually spin the impeller, the part will need to be replaced. A pump impeller may cease to spin after not being in use for a period of time. So if you shut off your water pump over the winter, this will be an important check.

Another impeller problem could be due to the part becoming detached. This could be due to the rubber stops on the shaft coming off. If you cannot find the rubber piece inside the unit, All Pond Solutions also offers a range of replacement shafts.

Air Lock

If you are experiencing no flow and any unusually loud sounds or hums coming from your water pump, this could be due to Vapour lock is when air gets trapped inside your pump. These pumps are not made to push air out, so an air bubble will get trapped. Fixing this is simple, tilt the pump so that the air pocket moves and can escape through the inlet/outlet.

General Checks To Complete Once A Month

  • Take apart the outer casing – generally, pumps will have clips on the side which make this very easy. Clean out the debris that has made its way inside the unit so that blockages do not occur.
  • Check the impeller. Open up the case where the impeller is housed and check if it is turning properly. Take this time to check of any signs of damage to the impeller and shaft and clean these pieces. 
  • If there are damages such as a snapped shaft, and you do not have spare replacements at home, at All Pond Solutions we stock a range of pond pump spares.
  • The impeller and shaft housing should be kept clean of dirt/rubble/limescale so that the pump is kept in good, working condition. 

Disclaimer: The maintenance tips stated above are relevant to general checks that pond keepers should make frequently. This will not apply to everyone as every person’s system will be different. Before making any sort of checks please read over the user manual or contact the manufacturer.

We advise that a professionally qualified electrician assists with pond pump checks dealing with power, as water and electricity can be fatal if not handled with extreme caution. We at AllPondSolutions cannot be held accountable for any instances of attempting these checks on your own. Please use your own discretion when making checks.

Making pump checks can be routine and safe as long as the units are turned off.