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How do submersible pumps work?

Posted by Rod Judge on

A submersible water pump, also known as an electric submersible pump, works under the surface by using submerged water pressure to fill the pump and then move the water to the desired location, either through a pipe, hose or tap.

They feature an hermetic (air tight) seal and are close-coupled where the motor is directly coupled to the pump shaft.

The submersible pump forces water to the surface by converting energy in the following way:

Rotary Energy > Kinetic Energy > Pressure Energy


Submersible Water Pump


Without requiring the effort necessary to move water into the pump, as the pump is already submerged in water, the efficiency of the pump is greatly enhanced. Natural water pressure is what forces the water into the pump, therefore most of the energy required is used for moving the water out of the pump.


Being submersed in water while operational, the noise of the pumps regular operation is dampened by the water.


Cavitation, or vapour filled cavities in liquid¹, is not a problem for submersible pumps, as the spike in pressure that causes it is not present when the pump is submerged in water.


Priming is not required as the pump is already submerged under water and filled.


While the advantages of using a submergible pump are clear, there is one key disadvantage that needs to be noted. Due to being submerged, the seals can perish and become corroded quicker than usual.

If seals to the pump crack and allow water into the motor, the pump will need to be repaired.

This can easily be avoided by regular checks and maintenance, which is essential and usual for all water pumps.

Take care of your submersible pump

A word of caution, submersible pumps are designed to function while submerged. The water acts as a natural coolant for the pump which generates heat while operating. Be sure to maintain water level and not to allow the water pump to run dry. This ca cause the pump to overeat and fail, and possibly cause damage to the pump.

Which Submersible Pump is best?

Choosing the best submersible pump will depend on the application and water volume required to be moved per minute.

Use our table to guide your decision, and if you still have questions, please get in touch with our knowledgeable team.

Submersible Pump CodeFlowHeadWeightPrice


13,500 Litres per hour8m6 Kg$129


85 Litres per minute50m12 Kg$441


300 Litres per minute12m18 Kg$384


200 Litres per minute8.5m16 Kg$323


85 Litres per minute35m12Kg$409


Submersible water pumps are a popular choice for water tank owners who wish to make use of the advantages such as low noise and low energy usage.

We stock and recommend Monza pumps, for their quality, reliability and durability.

Please get in touch with us today if you have any questions regarding water pump selection.