Pressure Washers, Foam Cannons and Adapters

Electric or gas, and what PSI and GPM mean

Cleaning power is the combination of pressure (PSI) and water flow (GPM), so look at both. Light electric washers around 2000 PSI and 1.5 GPM suit cars, furniture and patios, plug into a standard outlet and are quieter. Gas models with 4000 PSI or more and 4 GPM clean large concrete areas faster, strip heavy grime and work away from an outlet, but they are heavier, louder and need fuel and engine care. Higher PSI is not always better: it can etch wood, soft paint and siding.

Power supply, water supply and foam cannons

Check what the washer needs to run. An electric model draws substantial current, so use a grounded outlet with ground-fault protection and avoid thin extension cords. Gas models need fuel, oil and a flat, ventilated spot outdoors, never in a garage. Both need a water supply that can match their GPM, and the pump must be fed water before the motor starts, because running it dry damages it. A foam cannon attaches at the wand outlet; its thickness tends to depend on the washer's flow, so low-flow electric models make thinner foam.

Questions about Pressure Washers, Foam Cannons and Adapters

How much PSI do I need to wash a car?

A moderate electric washer, around 1500 to 2000 PSI, is enough for cars, furniture and light cleaning. Use a wide-angle tip and keep a safe distance, because very high pressure can damage paint, trim and seals. Gas models above 3000 PSI suit concrete rather than paintwork.

Does GPM matter as much as PSI?

Yes. PSI is the pressure that loosens dirt, but GPM is how much water carries it away. A washer with higher flow cleans faster at the same pressure, and rinses large areas more quickly. Compare cleaning power as PSI multiplied by GPM, but check each figure against your tasks.

Why won't my pressure washer build pressure?

Common causes are an inadequate water supply, a kinked or blocked hose, a clogged nozzle tip or a worn pump seal. Check the inlet filter and the nozzle first, make sure the water supply meets the GPM, and bleed air from the system before starting.