Shop for a surface pump and you quickly run into three words that get used loosely and sometimes interchangeably: self-priming, peripheral and jet.
They are not alternatives to each other in the way they are often presented. One describes how a pump gets started, and the other two describe how a pump builds pressure.
Understanding the distinction makes choosing a surface pump far simpler, because it tells you which design suits pressure boosting, which suits moving volume, and which suits drawing water up from a depth.
Self-priming: how the pump gets going
Self-priming describes a pump's ability to draw water up to itself on start-up, clearing air from the suction line without you having to fill that line first. A surface pump sits above the water, so on start-up its suction pipe can be full of air. A self-priming pump can evacuate that air and pull water up, usually up to a suction lift of a few metres. A pump that is not self-priming has to be primed by hand every time, and will lose prime if air gets in.
Crucially, self-priming is not a pump type, it is a feature. A jet pump can be self-priming, and so can a centrifugal transfer pump. It is the first thing to confirm on any surface pump, because it governs how easy the pump is to live with. The Speroni CA(M) self-priming jet pump is a good example of the feature and a type combined.
It is still recommended to install a foot valve for efficiency.
Peripheral: high pressure, modest flow
A peripheral pump, sometimes called a regenerative turbine pump, uses a small impeller with many short vanes around its edge. Water is recirculated and given a series of small pressure boosts as it travels around the casing, so a peripheral pump builds high pressure from a small, low-cost unit.
The trade-off is flow: peripheral pumps move modest volumes, so they shine where you need pressure rather than quantity, such as boosting supply to a few outlets or feeding a small system. The Speroni AKM60 and the brass-bodied Speroni KF(M) are typical peripheral pumps.
They are not the pump for filling or emptying a tank quickly, because that is a job for flow, not pressure.
Jet: drawing water up from a depth
A jet pump uses an ejector, a venturi arrangement that recirculates some of the pump's own output to create suction at the inlet. This lets a jet pump draw water from deeper than an ordinary surface pump can manage, which is why jet pumps are the choice for drawing from a shallow well, a borehole within reach, or a tank set below the pump. A self-priming jet pump like the Speroni CA(M) combines easy starting with the ability to lift water from a depth, which makes it a versatile garden, transfer and light irrigation pump.
Centrifugal, for moving volume
Alongside these sits the ordinary single-stage centrifugal surface pump, which is built for flow rather than high pressure. A pump like the Speroni CMX is the one you reach for to transfer water between tanks or move a large volume over a short distance. Where you need both volume and a fair bit of pressure, a horizontal multistage pump such as the Speroni RSX(M)4 stacks several impellers to build pressure while still moving useful flow.
Which one do you need?
Match the design to the job rather than the label. For pressure to a few outlets or a small system, a peripheral pump gives you the most pressure for the money. For drawing water up from a well, borehole or sunken tank, a self-priming jet pump is built for the lift. For moving volume between tanks or over a short run, a single-stage centrifugal pump is the efficient choice. And for both flow and pressure, look at a multistage pump. Whatever the design, check it is self-priming if it will sit above the water.
You will find all of these in our surface pump collection. If you are deciding between a surface pump and a submersible in the first place, our guide to surface pump vs submersible pump covers that, and the Water Pump Performance Calculator helps you size on flow and head.
Frequently asked questions
Is a self-priming pump the same as a jet pump?
No. Self-priming describes a pump's ability to draw water up and clear air from its suction line on start-up, and it is a feature rather than a type. A jet pump is a specific design that uses an ejector to draw water from a depth. A jet pump can be self-priming, but so can other surface pumps.
What is a peripheral pump best for?
Pressure rather than volume. A peripheral pump builds high pressure from a small, economical unit, which suits boosting supply to a few outlets or feeding a small system. It is not the right choice for moving large volumes quickly, where a centrifugal pump is better.
When do I need a jet pump?
When you need to draw water up from a depth that an ordinary surface pump cannot manage, such as a shallow well, an accessible borehole or a tank set below the pump. The ejector in a jet pump creates extra suction at the inlet, allowing it to lift from deeper than a standard centrifugal surface pump.
Which surface pump moves the most water?
For volume over a short distance, a single-stage centrifugal pump moves the most water, because it is built for flow rather than high pressure. If you need both flow and pressure, a horizontal multistage pump is the better balance. Peripheral and jet pumps prioritise pressure or lift over raw flow.
