CAT CLASS: HQ-10795

3-4 in Trash Pump

The 3-4 in Trash Pump is a mid-capacity dewatering unit designed to keep trenches and small excavations dry through rain events, typically delivering around 300 gallons per minute. It sits in the middle of the trash pump ladder, above the 2-3 in class and below the 4-6 in models. This size balances portability with enough flow to handle moderate water ingress on compact job sites.

255

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	3 in (76.2 mm)	Standard outlet size that determines hose compatibility and hydraulic performance.
Flow Rate	~300 gpm	Typical pumping capacity for managing moderate water accumulation in excavations.
Solids Handling	Up to 1 in spherical	Maximum size of debris and solids the impeller can pass without clogging.

How to choose

The 3-4 in Trash Pump is appropriate for trenches, small excavations, and foundation pits where rain or groundwater seepage produces moderate inflow that a smaller pump cannot sustain. When flow demands are lighter—such as a narrow trench in stable soil—the 2-3 in Trash Pump offers easier handling and lower fuel consumption. For larger excavations, dewatering sumps, or sites with heavy stormwater runoff, the 4-6 in Trash Pump provides the additional capacity needed to prevent flooding. Match pump size to the expected inflow rate and the duration of pumping required.

What this size handles

Dewatering a utility trench during a multi-day rain event
Keeping a small building foundation excavation dry while crews pour footings
Draining stormwater accumulation from a retention pond or low spot on a grading site
Managing groundwater seepage in a shallow sewer-line dig through saturated soil
Pumping out a flooded construction access road or staging area after heavy rainfall

Safety & operation

Position pump on stable, level ground and secure suction strainer below water surface to prevent air ingestion
Maintain adequate ventilation around engine exhaust; never operate in enclosed spaces
Inspect hoses and couplings for secure fit under pressure; unsecured discharge lines can whip and cause injury
Monitor fuel level and engine temperature during extended runs; allow engine to cool before refueling

Transport & logistics

Compact enough for bed-mount in a pickup truck or small utility trailer
Most units feature lifting handles or roll-cage frames for two-person loading
Standard ball-hitch utility trailer sufficient for towing to site

Power & supply

Typically powered by gasoline or diesel engines in the 5–8 hp range
Self-contained fuel tank supports several hours of continuous operation between refills
No external electrical supply required; engine-driven design for remote or off-grid sites

Frequently asked

What differentiates a 3-4 in trash pump from a standard centrifugal pump?

Trash pumps feature semi-open or recessed impellers and larger internal clearances, allowing them to pass small stones, mud, and organic debris without clogging—essential for construction dewatering where water quality is unpredictable.

How long can a 3-4 in trash pump run continuously?

Run time depends on fuel-tank capacity and engine load, but most units in this class operate 3–5 hours per tank under normal pumping conditions. Continuous duty requires periodic refueling and routine checks of oil level and coolant.

When should a larger 4-6 in pump be specified instead?

Specify the 4-6 in class when expected inflow exceeds 300 gpm, when pumping lift or distance requires higher head pressure, or when the excavation is large enough that flooding would halt work. The larger pump ensures adequate reserve capacity during peak storm events.