Water in a lift pit is one of those problems that stays quiet until it becomes expensive. A small amount of seepage corrodes equipment, trips safety circuits and can take a lift out of service, leaving residents, guests or staff without access and you with an urgent callout.
If you look after lifts in blocks of flats, hotels or commercial buildings, the right drainage pump keeps the pit dry, protects the lift and avoids repeat visits. This guide explains why water collects, what the rules say before you fit a pump, and how to choose a pump that actually does the job.
Why water collects in lift shafts and why it matters
Lift pits sit at the lowest point of the shaft, so water naturally finds its way in. Common sources include:
- Groundwater rising through the pit floor or walls
- Rainwater seepage, especially in ground floor and basement installations
- Burst pipes, washdown water or condensation
The Lift and Escalator Industry Association (LEIA) is clear that water ingress into lift pits is highly undesirable. It damages and deteriorates equipment, can render a lift unserviceable, and creates dangers and difficulties for anyone working in the pit. Standing water also accelerates corrosion of rails, fixings and electrical components, which shortens the life of the installation.
What to check before you fit a pump
A pump is often the practical answer, but LEIA guidance highlights a few things the lift owner should consider first:
- Structural advice. Forming a sump in the pit floor may affect the structural integrity of the pit, so advice should be sought from an architect, structural engineer or similar professional.
- Safe access. The lift will need to be isolated to allow safe access for maintaining the pump.
- Contaminated water. Water pumped from a lift pit is likely to be contaminated with oil and grease, so it cannot be allowed to enter the drains without special arrangements such as an oil separator. Follow the relevant pollution prevention guidance for your industry.
It is also worth remembering that lift installations are governed by the BS EN 81 family of standards and have specific requirements for removing water from the pit. If in doubt, involve the lift maintenance provider early.
How to choose the right lift shaft water pump
Lift pits are narrow, often dirty, and need to be kept as dry as possible. These are the factors that matter most:
1. Low level drainage
A standard submersible pump leaves a layer of water behind once the float drops. In a lift pit that residual water keeps corroding equipment. Look for a residue or “puddle sucker” pump that can draw the level down to around 1mm, so the pit is left nearly dry rather than just lower.
2. Automatic operation
Lift pits are unmanned, so the pump needs to switch itself on when water arrives and off when it has gone. A reliable level sensor or float that runs the pump on demand removes the need for anyone to attend, which is exactly what you want for a building you do not visit daily.
3. Head and flow to suit the discharge run
Head is how high the pump can lift water, and flow is how quickly it moves it. Check the vertical distance up the shaft to the discharge point and any horizontal run, then choose a pump with comfortable headroom above that figure. Use our pump performance calculator here.
4. Compact footprint and build quality
Pits are tight spaces, so a slim pump that fits the available area is essential. Because seepage water often carries sand and silt, durable components such as urethane impellers and silicon carbide seals will last far longer than basic plastic pumps.
5. A plan for contaminated water
Pair the pump with an oil separator or interceptor so the discharge meets environmental rules. This is a requirement, that protects you from pollution liability.
Pump types compared
| Pump type | Best for | Watch out for |
|---|---|---|
| Manual puddle sucker | Planned clear outs and occasional use where someone is on site to switch it on and off | Not suitable for unattended pits |
| Automatic sensor pump | Most lift pits. Runs on demand and pumps down to a very low level with no one present | Set the on and off levels correctly |
| Fixed sump pump station | Higher risk sites needing a permanent installation with a control panel and alarm | Higher cost and more install work |
A proven low level automatic option
For most lift pits an automatic low level residue pump hits the sweet spot of small footprint, reliable unattended operation and a very dry finish. A good example in this category is the Tsurumi LSC1.4S, a compact single phase pump that we supply and that performs well in lift shaft duty.
Its headline specification gives a sense of what to look for in this class of pump:
- Pumps water down to a 1mm level, so the pit is left effectively dry
- Maximum flow of 170 litres per minute and maximum head of 11 metres
- Choice of 25mm or 50mm outlet and a light 12kg body that fits tight pits
- Urethane impeller and silicon carbide seal for life in silty seepage water
The automatic sensor version uses two stainless steel probes set in moulded rubber. The pump starts when both probes sense water and keeps running on demand to hold the level below the probes. The probes also take optional extensions of a further 100mm, which lets you set a lower start level and pump the pit down further. That is exactly the setup a recent lift servicing customer of ours chose: the automatic pump with hose and the probe extensions, so the pit could be drawn down to a lower level.
This is one strong option rather than the only one. The principles above apply whichever brand you choose, but a low level automatic residue pump of this type is the right starting point for most lift shafts.
Other models worth considering
Depending on the depth of the pit and how much water comes in, two other pumps are worth a look alongside the LSC1.4S.
EVAK Residox 400
A close alternative to the LSC1.4S that also clears standing water down to around 1mm, but moves more water at 250 litres per minute against an 11 metre head. It has a cast iron housing, a stainless steel case and a 2mm free passage for light debris. A useful practical difference is that it needs no priming: you place it in the water and switch it on. The standard pump is manual, so for an unattended lift pit choose the automatic floor level sensor version. It comes with a one year warranty.
Tsurumi LB480 automatic
A more rugged submersible for deeper pits or formed sumps where the pump can sit submerged. It gives 225 litres per minute and an 11 metre head, with a chromium iron impeller and silicon carbide double mechanical seal built for silty, abrasive water, backed by a three year warranty. The sensor version works just like the LSC, starting when both probes sense water and holding the level below them, with an off level adjustable down to around 20mm and lower again using optional extension probes. It suits higher inflow or deeper shafts where you want extra headroom and durability.
Comparing the three side by side:
| Model | Pumps down to | Max flow | Warranty | Best for |
|---|---|---|---|---|
| Tsurumi LSC1.4S (auto) | 1mm | 170 L/min | 3 years | Compact pits and unattended low level drainage |
| EVAK Residox 400 (auto) | About 1mm | 250 L/min | 1 year | Higher flow with no priming needed |
| Tsurumi LB480 (auto sensor) | About 20mm | 225 L/min | 3 years | Deeper pits and formed sumps |
For a permanent, hands-off installation, the LSC1.4S is also available with a SwitcH2O float and control panel as a fixed setup, which suits managed buildings that want an alarmed system left in place.
Recommended setup for flats, hotels and serviced buildings
- Automatic low level residue pump sized to the pit and discharge run
- Sensor probes with extensions where the pit needs drawing down to a low start level
- Suitable discharge hose routed to the agreed discharge point
- Oil separator or interceptor so contaminated water can be discharged compliantly
- A maintenance routine to test the pump and keep the strainer and probes clear of debris
Need help choosing the right lift pit pump?
We are happy to help you choose the right pump, probe and hose for the job, whether that is over the phone or online. If your situation is more involved, with site-specific factors like pipe runs, head calculations, drainage layout or inflow rates, that moves beyond product selection into engineering. For those projects our Engineering Review Service can scope a proper assessment through our sister company FPS Environmental, so the system is sized on sound foundations rather than guesswork. Otherwise, get in touch with our team or browse our puddle pumps online.
Frequently asked questions
What is the best type of pump for a lift shaft?
An automatic low level residue pump, often called a puddle pump or puddle sucker, is the usual choice. It runs on demand without anyone present and can pump the pit down to around 1mm, leaving it effectively dry.
Can I just use a normal sump pump in a lift pit?
A standard sump pump leaves a layer of water behind when its float drops, and that residual water keeps corroding equipment. A low-level pump that clears down to about 1mm is far better suited to a lift pit.
Where can the pumped water go?
Water from a lift pit is usually contaminated with oil and grease, so it cannot enter the drains directly. It needs to pass through an oil separator or be handled in line with pollution prevention guidance.
Do I need building or structural advice before fitting a pump?
Yes. Forming a sump can affect the structural integrity of the pit, so LEIA advises seeking input from an architect or structural engineer, and the lift must be isolated for safe access during pump maintenance.
