PUMP CATEGORY

Site Drainage & Dewatering Pumps

Pumps for site drainage and dewatering: removing groundwater and surface water from trenches, excavations and working areas so the ground stays workable. Submersible, engine-driven and high-flow options in UK stock.

Read our guide: Water in an Excavation: Which Pump Do You Need?

See real flow figures by hose length

Products in range 26
From £270£225 (Exc VAT)
Best for Trenches & sites
Warranty Up to 3 years
26 products
Tsurumi★ 5.0

Tsurumi LB480 Contractor Pump – Manual & Automatic

  • Compact 0.48kW contractor pump, ideal for site drainage and confined-space dewatering
  • Lightest in the LB range at just 10.4kg, easy to carry and reposition around site
  • Available in Manual or Automatic (pendant float or sensor) versions
  • Top-discharge cooling allows running for extended periods with little or no water
  • Pumps up to 225 L/min to 11m head
£390.84 £325.70 (Exc VAT)
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Tsurumi

Tsurumi LB800 Contractor Pump – Manual & Automatic

  • Heavy-duty 0.75kW (800W) contractor pump for demanding site drainage
  • Higher output than the LB480, up to 310 L/min and 15m head
  • Available in Manual or Automatic (pendant float or sensor) versions
  • Top-discharge design runs reliably for extended periods with little or no water
  • Compact and portable at 13kg, with selectable horizontal or vertical discharge
£548.40 £457.00 (Exc VAT)
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FPS Engineered

High Flow Petrol Water Pump Kit | Honda WB30, 1,100 L/min

  • Around 1,010 L/min through the kit, roughly 60,000 litres an hour at a 2m lift
  • Both hoses supplied, 10m reinforced for suction and 10m layflat for delivery, both 80mm
  • 80mm throughout loses under 3m of head across the full run, so you keep 92% of rated flow
  • Honda GX160, 5.5hp, with Oil Alert, handling solids to 6mm
  • Suction lift to 8m, no power supply needed
£730.00 £608.33 (Exc VAT)
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FPS Engineered

Petrol Flood & Site Pump Kit | Honda WB20 - 2 Inch

  • 474 litres per minute through the kit. Around 28,000 litres an hour at typical lift.
  • Both hoses included. 6 m reinforced for suction, 30 m layflat for reach. The pump alone comes without them.
  • Cast iron volute and impeller. Abrasion resistant, so silt and sand do not finish it.
  • Honda GX120 with Oil Alert. The commercial 4-stroke, in a tubular steel crash frame.
£557.99 £464.99 (Exc VAT)
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FPS Engineered

Site Drainage Pump Kit | EVAK Drainox 400 & 750

  • 190 to 257 litres per minute through the supplied hose. Choose the pump to match your lift.
  • Stainless steel and cast iron build. Strainer base, cover and handle in stainless, FC20 cast iron housing.
  • Automatic operation. Starts and stops with the water, so it can be left working in an excavation.
  • 5 mm free passage. Abrasion-resistant Hytrel vortex impeller for grit and site water.
£439.49 £366.24 (Exc VAT)
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FPS Engineered

Silty Trench Dewatering Pump Kit | EVAK Trenchman 400

  • Built-in agitator. Stirs settled silt back into suspension so it can be pumped away, not left behind.
  • 15 mm free passage. Three times the Drainox, for fines, grit and small stones.
  • Around 189 litres per minute through the supplied hose. Roughly 11,300 litres an hour at site lift.
  • 20 m of 50 mm layflat included. Automatic float control, so it works while you do.
£366.49 £305.41 (Exc VAT)
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FPS Engineered

Contractor Dewatering Pump Kit | Tsurumi LB480

  • Around 190 litres per minute through the supplied hose. Roughly 11,400 litres an hour at site lift.
  • 20 m of 50 mm layflat included. Enough reach for most excavations, and it rolls down to almost nothing.
  • 110 V or 230 V. Site transformer or building mains, identical kit either way.
  • Tsurumi durability. The pump hire fleets keep buying, from a maker in business since 1924.
£428.33 £356.94 (Exc VAT)
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Honda★ 5.0

Honda WX10 Petrol Water Pump | Lightweight 1 Inch Pump

  • Lightweight 1 inch pump, just 6.1kg
  • Honda GX25 4-stroke engine, easy start, no fuel mixing
  • Up to 140 L/min and 36m head for clean water transfer
  • 360 degree operation, runs and stores at any incline
£418.00 £348.33 (Exc VAT)
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Tsurumi

Tsurumi LB1500 Contractor Pump – Heavy Duty Manual

  • Powerful 1.5kW contractor pump with the highest flow and head in the LB range
  • Moves up to 420 L/min to 17.5m head for larger-volume site drainage
  • Manual operation with a fixed vertical discharge for maximum strength
  • Built for tough, high-demand dewatering on construction and flood sites
£2,935.00 £2,445.83 (Exc VAT)
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Tsurumi

Tsurumi TD Petrol Diaphragm Trash Pump

  • Suitable for trash, sand, silts and solids up to 30mm
  • OHV Honda petrol powered automatic priming diaphragm pump
  • Can run dry for short periods
£2,185.00 £1,820.83 (Exc VAT)
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Site Drainage & Dewatering Pumps:

Site Drainage & Dewatering Pumps: Keeping Trenches, Excavations and Sites Dry

Site drainage and dewatering is the controlled removal of groundwater and surface water from a trench, excavation, foundation or working area so the ground stays workable. A dewatering pump moves that accumulated water out faster than it flows back in.

These are heavy-duty submersible pumps, or, where there is no mains power, engine-driven surface pumps, built for dirty water, suspended solids and continuous duty. We have grouped the pumps we supply most often by the job, so you can find the right one quickly.

Sizing tool

Water Pump Performance Calculator.

Indicative only This calculator uses a simplified parabolic pump curve and the Hazen-Williams friction loss formula. Real pump curves vary by model. Results are a guide only. Always verify against your pump's published performance data and consult our team if you are unsure.
How to use this calculator
  1. Enter your pump's max flow rate and max head from the datasheet or product listing. These are the peak figures at either end of the pump curve: max flow at zero head, max head at zero flow.
  2. Select your hose or pipe type. Suction and delivery hose is the most common for portable pumps. Layflat hose is used for longer water transfer runs. Rigid PVC pipe is for fixed installations.
  3. Choose the diameter to match your pump outlet or the hose you intend to use.
  4. Enter the total length of your hose or pipe run in metres from pump outlet to discharge point.
  5. For rigid pipe, add any 90 degree bends using the counter. Each bend adds resistance equivalent to extra pipe length.
  6. Read the results. The calculator estimates your duty point: the flow rate and head your pump will likely deliver through that hose run. For longest pump life, aim for a duty point in the mid-curve range (roughly 40 to 70% of max flow).
Step 1: Your pump specification

Labelled "max flow" or "free flow" on the datasheet: the flow at zero back pressure

Labelled "max head" or "total head": the maximum height the pump can push water at zero flow

Step 2: Your hose or pipe

Suction / delivery hose

PVC reinforced, helix coil, smooth bore: max 6 bar working pressure

Vertical rise from pump to outlet. Enter 0 if pumping on flat ground

Results
Friction loss per 10 m
–
m head / 10m
Total friction loss
–
metres head
Head remaining after friction
–
metres head
Estimated flow at duty point
–
L/min (indicative)
Buying guide

Site drainage and dewatering, by job.

What these pumps do, how to pick by the job, power options, and related categories.

Trench, foundation and excavation dewatering

The single most common job. Groundwater and rainwater fill trenches, foundations and excavations, halting work until the area is dry. These pumps are built to handle dirty water, suspended solids and continuous duty in harsh conditions.

The EVAK Trenchman has a built-in agitator, making it ideal for trench dewatering where sand and silt would clog a standard pump. The Tsurumi LB series (LB480, LB800 and LB1500) is the industry-standard contractor pump and can run for extended periods with little or no water. The Tsurumi HS series and EVAK Drainox are robust mid-range options. For the highest flow rates, the APP HD-15 moves up to 830 litres per minute.

Engine-driven pumps for sites without power

Early-stage sites, remote works and emergency response often have no mains power. Engine-driven pumps remove that dependency. Petrol pumps are quick to deploy and handle clean to lightly contaminated water; diesel diaphragm pumps handle heavy solids and can run dry indefinitely.

The Honda WX and WB petrol pumps are popular with hire fleets and utility contractors for their reliability and self-priming design. The Drymax diesel trash pump handles sludge, mud, sand and solids up to 40mm for the most demanding dewatering. The Tsurumi TD petrol diaphragm pump is a compact alternative for trash water with solids up to 30mm. See the full engine-driven pumps range.

High flow and high head for major dewatering

For cofferdams, large excavations, watercourse diversion and major dewatering schemes, you need volume or pressure. The APP HD-15 is a high-flow submersible at up to 830 litres per minute. The Tsurumi LB1500 handles heavy-duty 400V three-phase work. The Tsurumi NK is a single-phase drainage pump capable of large flows at high heads, and the APP KHL-20 delivers 25 metres of head where water must travel a long distance or to a height. See high-flow and high-head pumps.

Slurry, sludge and heavy solids

Some site water carries more than silt. Concrete washout, slurry from piling rigs, mud from heavy plant and waste from groundworks all need a pump built for solids. Choose a slurry pump with an agitator to keep solids in suspension and stop the pump clogging.

The EVAK Agivort is our recommended slurry pump, and the Drymax and Tsurumi TD diaphragm pumps handle the heaviest trash and sludge. See dirty water pumps.

Welfare units and foul water

Welfare units on site produce foul water, which needs a dedicated solids-handling sewage pump rather than a drainage pump.

The APP BCV handles solids from 50mm to 80mm and is a standard choice for site sewage. For the wider range, see our sewage and dirty water pumps.

110V for site safety

Most UK sites require 110V equipment for safety. Many of the pumps here are available in a 110V variant; see our dedicated 110V water pumps collection and select the 110V option on the product page where it is offered.

Related pump categories

Buying for a contractor, groundworker or hire fleet? See our Water Pumps for Construction & Civil Engineering hub, organised by the whole job.

Why buy your site drainage and dewatering pumps from us

We have supplied site drainage and dewatering pumps to UK contractors, hire fleets, housing developers, water companies and facilities teams since 2012. Our parent company Flood Protection Solutions Ltd is an SSIP and CHAS accredited supplier, and we hold the most popular contractor pumps in stock for next working day delivery on orders placed before 2pm.

  • Trade-tested ranges from EVAK, Tsurumi, APP, Honda and Stream
  • Next working day delivery on almost all stock items, ordered before 2pm
  • Long warranties, including 3 year cover on many products
  • Technical support on 0115 987 0358 or via enquiries@floodprotectionsolutions.co.uk
Common questions

Frequently asked questions.

Which pump do I need to dewater an excavation?

For groundwater a contractor pump such as the Stream SPK450A, Tsurumi LB480 or HS2.4S are the common choices. If the water is full of silt or grit, an agitator pump such as the EVAK Trenchman keeps the solids moving so the pump does not clog.

Should I use a 110V or 230V site pump?

Most UK building sites require 110V tools run from a site transformer, so many of our site pumps come in 110V. Use 230V where the site allows it, for example domestic projects or buildings with mains power.

Can a site pump handle silty water?

Site drainage pumps are built to tolerate sand and silt, but fine silt can settle around the inlet and slow the pump down. Agitator pumps such as the EVAK Trenchman or Agivort stir it back into suspension so it can be pumped away.

What if there is no power on site?

Use an engine-driven pump such as the Honda WB20 or WB30, or a trash pump such as the DryMax. They are self-priming surface pumps, so the suction hose goes into the water and the pump sits on dry ground.

Do you sell complete dewatering kits?

Yes. Our kits combine the pump with matched layflat hose and fittings, for example the Contractor Dewatering Pump Kit with the Tsurumi LB480 and the Silty Trench Dewatering Pump Kit with the EVAK Trenchman 400.