Cellars are the lowest point in the house, so when water gets in, it has nowhere else to go. Whether it is rising groundwater, a leak, or floodwater finding its way in, a wet cellar quickly leads to damp, damaged belongings, and expensive repairs.
The good news is that the right cellar water pump solves most of these problems, either by clearing water after a flood or by removing it automatically before it ever builds up.
This guide explains the main types of cellar pump, when to use each one, and the key features to check before you buy. It is written for UK homes, where older properties with brick or stone cellars are common and the problem is often groundwater rather than a one-off flood.
Why do cellars flood?
Most wet cellars in the UK come down to one of these causes:
• Rising groundwater, especially in winter or after prolonged rain
• Surface water flooding entering through doors, light wells, or coal chutes
• Seepage through walls and floors in older brick or stone cellars
• Burst pipes or appliance leaks from plumbing routed through the cellar
The cause matters because it decides the type of pump you need. A one-off burst pipe needs a portable pump for an hour. Groundwater that returns every winter needs a permanent automatic system.
The two main types of cellar pump
1. Portable pumps for clearing floodwater
If you need to get water out of a flooded cellar quickly, a portable submersible pump is the answer. You lower it into the water, run a hose up the steps or out of a light well, and let it pump.
For cellars, a puddle pump (also called a residue or low-level pump) is usually the best choice. Standard submersible pumps stop working with 30 to 50mm of water left behind. A puddle pump keeps going down to just a few millimetres, which matters when you are trying to dry a floor out properly.
Points to check:
• Flow rate: a typical domestic cellar flood is handled comfortably by a pump moving 100 to 200 litres per minute
• Head height: the pump must lift water from the cellar floor up to ground level and out, so allow at least 3 to 5 metres of head with capacity to spare
2. Permanent sump pump systems
If your cellar takes on water regularly, pumping it out by hand each time is not a solution. A cellar sump pump sits in a chamber (the sump) set into the lowest point of the floor. Water drains into the chamber, a float switch detects the rising level, and the pump automatically discharges it away from the property.
There are two ways to do this:
• A pump in an existing or site-built chamber: many older cellars already have a sump. An automatic submersible pump with a suitable float switch can often be fitted straight in.
• A packaged pump station: a ready-made chamber, pump, and pipework supplied as one unit. These are quicker to install, sealed against odours, and can be specified with twin pumps for backup.
If your cellar has been tanked or fitted with a cavity drainage membrane, a sump and pump system is a standard part of that setup. The membrane channels water to the sump, and the pump removes it.
Key features to look for in a cellar pump
• Automatic operation: a float switch or electronic sensor means the pump runs only when needed and protects the cellar while you are away
• Low-level switching: cellars with shallow sumps need a pump designed to switch on at low water levels
• Solids handling: groundwater is rarely clean, so look for a pump that passes small solids without blocking
• Reliability and duty cycle: a pump that runs every winter needs to be built for repeated use, not a one-off emergency
• Backup options: for high-risk cellars, a twin pump station or battery backup covers pump failure and power cuts
Common mistakes when choosing a cellar pump
• Buying a clean water pump for dirty groundwater: it will clog and burn out
• Ignoring switch-on level: a standard float switch may need more water depth than a shallow cellar sump allows
• Undersizing the head: measure the full lift from the cellar floor to the discharge point outside, plus hose length
• No backup for a converted cellar: if the space is a bedroom or office, a single pump with no failover is a real risk
• Discharging to the wrong place: water should go to a suitable drain or soakaway away from the walls, not straight back beside the foundations
Case study: keeping a flooding cellar dry without being there
A customer called us after their cellar had flooded repeatedly. Each time, they had to be at home to set up a pump and watch it run, and they wanted a way to keep the water at bay without monitoring it. This is exactly what automatic pumps are made for: a sensor or float switch starts the pump the moment water appears and stops it once the cellar is clear, whether anyone is home or not.
We also recommended suction and delivery hose rather than layflat. Layflat hose is cheaper but kinks easily when water is being pumped up and out, which is almost always the route in cellar flooding. Reinforced suction and delivery hose holds its shape up steps and over obstacles, so the pump keeps working at full flow.
Like all pumps, you must work out the distance and height you are pumping the water before choosing a model. Our pump performance calculator does the maths for you, accounting for hose length and friction loss.
Which setup is right for you?
• One-off flood or burst pipe: portable puddle pump,.
• Cellar that floods occasionally: automatic submersible pump kept on standby, or fitted in an existing sump
• Regular groundwater or a converted cellar: permanent sump chamber or packaged pump station, ideally with twin pumps or battery backup
Conclusion
Match the pump to the problem. Portable puddle pumps clear floods fast, while a permanent automatic sump system deals with recurring groundwater before it becomes damage. If you are unsure what your cellar needs, measure the head height, think about how often water appears, and choose automatic operation wherever the risk is ongoing.
Whatever your situation we have the right pump for you.
