CAT CLASS: HQ-10780

4-6 in Centrifugal Dewatering Pump

The 4-6 in centrifugal dewatering pump is a mid-capacity class designed for sustained dewatering of clear excavations and water truck fill station operations. This size sits in the middle of the centrifugal dewatering ladder, above the 3-4 in class and below the 6-8 in class. Discharge ports typically range from 4 to 5 inches, with flow capacities from approximately 420 to 3,200 gallons per minute and heads reaching up to 225 feet.

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Pick a size class — capacity and reach differ across the range.

Key specifications

Specification	Typical range	What it means
Discharge Port Diameter	4–5 in (10.2–12.7 cm)	Connection size for discharge hose or pipe; determines compatible fittings and dictates maximum solids pass-through.
Flow Rate	420–3,200 gpm	Volume pumped per minute; higher rates suit active excavation dewatering, lower rates match groundwater seepage control.
Maximum Head	51–225 ft (15.5–68.6 m)	Vertical lift plus friction losses the pump can overcome; critical for uphill discharge routing or deep excavations.

How to choose

This size class is the appropriate choice when sustained flow rates between 400 and 3,200 gpm are required for dewatering clear water from excavations, trenches, or cofferdams, or when supplying a water truck fill station with continuous high-volume delivery. The 3-4 in Centrifugal Dewatering Pump is the better fit for lower-volume applications such as shallow trenches, sump drainage, or jobs requiring portability over capacity. Step up to the 6-8 in Centrifugal Dewatering Pump when flow demands exceed 3,000 gpm, such as large-scale foundation dewatering, quarry operations, or flood control scenarios requiring maximum discharge volume.

What this size handles

Sustained dewatering of a mid-sized building foundation excavation with active groundwater inflow
Continuous pumping from a cofferdam during bridge pier construction in a riverbed
Filling water trucks at a dust suppression station on a highway widening project
Removing storm water accumulation from a deep utility trench over multiple shifts
Groundwater control for a below-grade parking structure excavation in saturated soil
Transferring water from a retention basin to discharge point several hundred feet away

Safety & operation

Discharge hoses must be secured to prevent whipping if connections fail under high flow pressure
Suction screens require periodic inspection to prevent clogging and cavitation damage to the impeller
Engine exhaust and hot surfaces present burn hazards; maintain clearance zones around operating units
Water discharge routing must avoid undermining excavation slopes, footings, or adjacent structures

Transport & logistics

Most units in this class mount on skid bases or wheeled trailer frames suitable for towing with a pickup truck or small service vehicle
Larger models may require flatbed trailer transport or forklift loading due to weight and footprint
Discharge hose and suction piping typically transport separately on reels or in bundles

Power & supply

Diesel engine prime movers are standard, with fuel tanks supporting eight to twelve hours of continuous operation
Electric motor models require 480V three-phase service and appropriately rated breakers or generator sets
Fuel consumption and electrical load scale with flow rate and head requirements

Frequently asked

How does head pressure affect flow rate in this size class?

Flow rate decreases as head (vertical lift plus friction) increases; a pump rated for 2,000 gpm at 50 ft of head may deliver only 1,200 gpm at 150 ft. Consult pump performance curves to match site conditions.

Can this size handle solids or only clear water?

Centrifugal dewatering pumps in this class are designed for clear water or minimal suspended fines. For slurries, mud, or debris-laden water, a trash pump or submersible slurry pump is the appropriate choice.

What distinguishes a 4-inch model from a 5-inch model within this band?

Discharge port diameter correlates with maximum flow capacity and the size of solids that can pass; 5-inch models generally deliver higher gpm and accept slightly larger particulates, but both serve the same application range.

Compare popular models

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Normalised to the same units. A dash means the figure was not published.

Model	Flow rate	Max head	Engine power
Honda WT40	423 gpm	82 ft (25.0 m)	-
Cornell 4SP	2,250 gpm	225 ft (68.6 m)	-
Godwin CD103M	1,020 gpm	51 ft (15.5 m)	-
Godwin HL130M	1,500 gpm	191 ft (58.2 m)	-
Cornell 4616SM	3,200 gpm	-	-
Cornell 4617ZX	2,600 gpm	-	-