It is one of the most common questions we are asked, and the answer almost always comes down to one thing: where the water is in relation to the pump.
A submersible pump goes into the water and pushes it out from below. A surface pump stays out of the water, dry, with pipes running to the water source on one side and to the delivery point on the other. Neither is better in general; they are built for different jobs, and choosing the wrong type is the usual reason a pump underperforms.
The quick answer
Use a submersible pump when you are removing water from somewhere: a flooded cellar, a sump, a chamber or a hole on a building site. The pump sits in the water and you want it gone. Submersibles also suit occasional use, emergencies, and confined spaces a surface pump cannot sit above.
Use a surface pump when you are moving, boosting or circulating water from a controlled source such as a tank, pond, stream or pool. The pump stays dry and accessible, which suits continuous running and jobs like pressure boosting, sprinkler and irrigation supply, and pool circulation.
The deciding factor: how far the water sits below the pump
The most important check for a surface pump is how far it can draw water up to itself before it can deliver any, and there is a firm limit. A surface pump that lifts water up to itself, known as a self-priming pump, can usually manage around 7 to 8 metres of lift, and no more, regardless of motor power.
If the water sits more than about 8 metres below the pump, a surface pump will not draw it, and you need a submersible or a borehole pump that sits down in the water instead. A practical tip for any surface pump mounted above the water: fit a foot valve, a one-way valve on the bottom of the suction pipe that keeps the pipe full of water between runs so the pump starts reliably.
Side by side
| Surface pump | Submersible pump | |
|---|---|---|
| Where it sits | Dry, beside or above the water | In the water |
| Best for | Transfer, boosting, circulation, irrigation, pools | Drainage, flooding, sumps, dewatering |
| Water source | Tank, pond, stream, pool, rainwater | The water being removed |
| Lift from below | About 7 to 8 metres maximum | Not a factor, it sits in the water |
| Servicing | Easy, the pump is dry and accessible | Must be lifted out of the water |
| Typical use | Continuous running | On and off as needed |
What surface pumps are used for
It helps to think in terms of the job rather than the product. A surface pump is usually doing one of these:
- Transfer: moving water from a source at or above pump level to somewhere else.
- Drawing water up: pulling water from a tank, stream or rainwater store below the pump, within the 7 to 8 metre limit.
- Pressure boosting: delivering water that is already available at higher pressure for sprinklers, irrigation, fire systems or cooling.
- Pool circulation: continuous-duty pumps with a strainer basket, built to run through the season.
- Specialist fluids: seawater, light chemicals and oils, where the pump material matters most.
You can see the full range, grouped by these jobs, on our surface pumps collection.
Many general-purpose surface pumps, including the popular Speroni range, are not WRAS approved, meaning they are not certified for mains drinking water in the UK. They are intended for non-potable duties such as irrigation, pool and pond, sprinklers, fire booster and rainwater.
Still not sure?
Our Pump Finder will point you in the right direction. If you are replacing a pump, send us the make and model from the old one and we will match it.
Frequently asked questions
What is the difference between a surface pump and a submersible pump?
A surface pump sits out of the water with pipes connecting it to the source. A submersible pump goes into the water and pumps it out from below. Surface pumps are easier to service and suit continuous transfer and boosting; submersibles suit drainage and confined spaces.
How far above the water can a surface pump sit?
A self-priming surface pump can usually draw water up from about 7 to 8 metres below it, and no more. Beyond that you need a submersible or borehole pump. A foot valve on the bottom of the suction pipe makes starting faster and more reliable.
Can I use a surface pump to drain a flooded basement?
No. Surface pumps are not designed for draining flooded areas. Use a puddle pump or a submersible drainage pump for that. Surface pumps are for controlled transfer, boosting or circulation.
