A surface pump can only suck water up so far, about eight metres in the real world, before physics gets in the way. Drop the pump into the liquid instead and that limit disappears. Submersible pumps are sealed pump-and-motor units that work fully underwater, pushing liquid up to the surface rather than drawing it from above, which is why they handle drainage, sewage, dewatering and water supply so reliably where surface pumps would struggle.
We supply submersible pumps from Calpeda, Dreno Pompe, Ebara, JS Pumps, Koshin, KSB, Lowara, Pedrollo and Pentax, and can source other makes for a specific job. The ranges are below, or call +44 1332 913500 for help choosing.
A submersible pump, also called an electric submersible pump or ESP, is a hermetically sealed electric motor close-coupled to a pump body, with the whole unit lowered into the liquid it pumps, be that clean water in a tank, sewage in a wet well or floodwater on a site. The motor is sealed against water getting in and cooled by the surrounding liquid, while the pump pushes flow up a discharge pipe to the surface.
Working below the surface, the pump pushes rather than pulls, which removes the suction-lift ceiling that limits surface pumps and sidesteps the priming and cavitation trouble that comes from trying to draw liquid up from depth. A submersible water pump can run at almost any depth, bounded mainly by cable length and discharge head.
Drainage and dewatering pumps handle clean or lightly dirty water, draining flooded basements, excavations, sites, tanks and cellars. They are compact, portable and often have a float switch for automatic running, in flows from a few litres a minute up to several hundred cubic metres an hour.
Submersible sewage pumps take on raw sewage and wastewater with soft solids, fibres and debris. A submersible sewage pump uses a vortex or channel impeller that passes solids without blocking, and usually sits in a pumping station or wet well, in single-phase form for domestic and small commercial work and three-phase for industrial and municipal duty.
Grinder pumps are a sewage variant with a cutter that shreds solids and fibres before they reach the impeller, used in pressure sewer systems and where the discharge pipework is small-bore.
Clean water and borehole pumps include the multistage submersible pumps used in boreholes and wells for water abstraction. For borehole-specific duty, see our borehole pumps page.
Slurry and sludge pumps are heavy-duty units with hardened impellers, wear plates and agitators for abrasive slurries, bentonite, mining tailings and thickened sludge.
At heart an electric submersible pump is a centrifugal pump: the sealed motor drives an impeller that throws liquid outward, turning motor energy into velocity and then pressure. Single-stage pumps, one impeller, cover drainage, sewage and general transfer; multistage pumps, several impellers in series, handle deep well and borehole work where high head is needed. The motor is sealed and cooled by the surrounding liquid, power comes down a submersible-rated cable, and most pumps carry thermal overload protection and can take float switches, level controllers or variable speed drives for automatic running.
Construction follows the duty. Cast iron is standard for drainage and sewage; stainless steel, 304 or 316, suits corrosive liquids, food-grade work and potable water; hardened chrome iron or Ni-Hard impellers and wear plates go into abrasive slurry duty. Cables, seals and O-rings are all rated for continuous immersion.
We supply electric submersible pumps from a broad set of manufacturers, Calpeda, Dreno Pompe, Ebara, JS Pumps, Koshin, KSB, Lowara, Pedrollo and Pentax, giving the range to match the pump to the job, and we source other makes where a specific requirement calls for it.
Start with four questions: what liquid you are pumping (clean water, sewage, sludge, slurry, chemical), what flow rate you need, what total head the pump must deliver (vertical lift plus friction losses), and what solids it has to pass. Then consider single or three-phase power, automatic or manual running, portable or fixed, and any certifications needed such as ATEX for hazardous areas or WRAS for potable water. Tell us the application on +44 1332 913500 and we will specify the right submersible pump.
If your questions have not been answered here, get in touch with our team for more information.
A sealed pump-and-motor unit made to run fully underwater. Because it sits in the liquid, it pushes flow up to the surface rather than pulling it, which removes suction-lift limits, priming trouble and cavitation. Submersible pumps are also known as electric submersible pumps, or ESPs.
A submersible pump sits in the liquid and pushes it up; a surface pump sits above and draws it up by suction. Submersibles work at almost any depth and are not capped by suction lift, around eight metres for surface pumps. Surface pumps are easier to reach for maintenance but cannot work where the depth beats their suction.
A submersible pump made specifically for raw sewage and wastewater carrying soft solids, fibres and debris, using a vortex, channel or grinder impeller that passes or shreds solids without blocking. It is the standard in domestic, commercial and municipal foul water stations.
No. A clean water pump has a close-tolerance impeller that blocks on solids and fibres. Sewage needs a submersible sewage pump with a vortex, channel or grinder impeller built to pass or macerate solids. Use the wrong type and you get blockages, damage and failure.
There is no fixed limit. Cable length, discharge head and the pump’s construction set the practical depth. Drainage and sewage pumps work in a few metres of liquid; borehole submersible pumps routinely run at 100 metres or more, with some rated for several hundred.
A well-specified pump in a sound installation usually lasts eight to fifteen years. Sewage pumps can be shorter-lived given the duty. Lifespan turns on the duty cycle, the fluid, operating temperature, correct sizing and protection against dry running and overload. All the brands we supply have spares readily available.
