The submersible pump is becoming more and more important than the dry pump type. The submersible pump is usually also capable of functioning in dry locations, thus they can be used at places where there is a chance of flooding.

The construction of the submersible pump is slightly different, because the impeller is located directly onto the combined motor and pump shaft. The drive motor, usually a squirrel cage induction motor, is completely sealed by the axial and radial O-rings. The liquid is sealed by double mechanical seals from the drive motor. The important factors of reliability and safety depends on the type of bearings, the size of the shaft and the method of sealing.

An advantage of the pump is it's ability to be able to fit various sizes of separate motor units in it's pump casing. Some pumps are also able to convert from through-flow to free-flow impeller on site.