CAT CLASS: HQ-10796

4-6 in Trash Pump

The 4-6 in trash pump class is sized for active excavations and small-line bypass applications requiring approximately 500 gallons per minute. This mid-range segment sits between the 3-4 in class for smaller dewatering tasks and the 8+ in class for large-volume municipal or industrial work. Models in this band feature 4 in discharge ports and are supplied by Tsurumi and Gorman-Rupp.

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Models

Brands

Cat classes

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

Key specifications

Specification	Typical range	What it means
Discharge port diameter	4 in (10.2 cm)	Standard connection size across models in this class for coupling to discharge piping.
Flow capacity	~500 gpm	Target pumping rate for working excavations and bypass operations at design head.
Solids passage	Varies by impeller design	Trash pumps accommodate debris and solids larger than clean-water centrifugal pumps handle.

How to choose

Choose a 4-6 in trash pump when flow requirements approach 500 gpm and discharge piping is 4 in, typical of working excavations, utility trenches under active dewatering, or bypassing flow around a small water or sewer main. For lighter dewatering—foundation trenches, shallow pits, or flows below 300 gpm—the 3-4 in Trash Pump class offers easier handling and lower fuel consumption. When municipal bypass, large excavation dewatering, or flows exceeding 1,000 gpm are required, step up to the 8+ in Trash Pump class with its significantly larger discharge and higher-volume impellers.

What this size handles

Dewatering a working excavation for utility installation with continuous groundwater inflow
Bypassing flow around a 6–8 in water main during repair or replacement
Pumping from a sump or wet well serving a mid-sized construction site
Handling runoff and seepage in trenching operations with moderate solids content
Transferring water from retention basins or temporary holding ponds
Controlling water levels in cofferdam or caisson construction

Safety & operation

Ensure suction strainer is clear and properly seated to prevent debris from damaging the impeller
Monitor discharge pressure and flow to detect clogging or cavitation conditions
Maintain safe distances from rotating couplings and belt drives during operation
Secure pumps on stable ground or trailer to prevent tipping or movement under vibration

Transport & logistics

Commonly trailer-mounted or skid-mounted for towing behind a pickup or utility truck
Requires moderate lifting capacity for crane or forklift placement if skid-mounted
Typical setup involves positioning near discharge point and running suction/discharge lines

Power & supply

Diesel-powered models with onboard fuel tanks for field independence
Electric models available for sites with three-phase power and no emissions restrictions
Fuel consumption and runtime depend on load, head, and engine size

Frequently asked

What distinguishes a 4-6 in trash pump from a 3-4 in model?

The 4-6 in class delivers approximately 500 gpm through a 4 in discharge port, roughly double the flow of most 3-4 in models, and is built for higher-volume excavation dewatering and bypass applications.

Can a 4-6 in trash pump handle sewage or highly contaminated water?

Trash pumps are designed for solids-laden water and construction runoff; for raw sewage or chemical-laden liquids, verify impeller and seal materials are compatible or consult a solids-handling sewage pump.

When should an operator choose the 8+ in class instead?

Step up to 8+ in trash pumps when flow requirements exceed 1,000 gpm, discharge piping is 6 in or larger, or municipal bypass and large-scale dewatering demand higher capacity.