Choose the pump type by application first. Then size by required flow, total dynamic head, suction conditions and solids content.
Best for flooded rooms and cellars: submersible drainage pumps
Submersible drainage pumps sit in the water and move it vertically through a discharge hose or pipe. Models differ mainly in capacity, maximum head, minimum residual water level and the size of solid particles they can pass.
Waterpump UK currently highlights the DAB Nova Up 300 M-AE for basement and room drainage, with about 10,000 l/h maximum capacity, around 7.5 m head and 10 mm solids passage.
Best for stable household pressure: electronic booster systems
Electronic pressurization systems such as the DAB Esybox Mini 3 use variable-speed control to maintain pressure as household demand changes. DAB publishes up to 4.8 m³/h flow and 55 m head for the Mini 3.
This category is very different from a simple transfer pump because controls, non-return protection and pressure management are integrated.
Best for gardens and rainwater reuse: self-priming surface pumps
Surface pumps work well when the source is a rainwater tank, shallow well or other accessible supply. They are typically easier to service than a submerged pump but are constrained by suction lift.
Waterpump UK lists many garden/self-priming models by number of simultaneous sprinklers, maximum head and flow.
How to avoid buying the wrong pump
Do not size from maximum flow alone. A pump may deliver a high flow at near-zero head but much less at the pressure your system actually needs.
Check the performance curve, the vertical lift, pipe friction, suction depth and whether the water contains solids.