A pressure washer turns a garden hose into a cutting tool. Used right, it cleans a driveway, a deck, or siding in an afternoon. Used wrong, it gouges wood, strips paint, etches concrete, and injures people — the same jet that lifts dirt lifts skin. Most of the damage comes from two mistakes: the wrong nozzle and standing too close. Get those right and the rest is technique.
| Nozzle | Spray angle | Use it for |
|---|---|---|
| Red — 0 degrees | A needle jet | Almost nothing. It cuts wood and skin. Avoid it. |
| Yellow — 15 degrees | Narrow fan | Concrete, brick, and stubborn stains on hard surfaces |
| Green — 25 degrees | Medium fan | General cleaning: driveways, patios, siding |
| White — 40 degrees | Wide fan | Soft surfaces: wood decks, vinyl siding, cars |
| Black — soap | Low pressure | Applying detergent before the real wash |
Start with the widest nozzle that does the job and only go narrower if the dirt stays. The pressure washer buying guide covers PSI — how much pressure you actually need for each job — and the nozzle is what controls where that pressure goes.
Read the manual and check the machine. Know your PSI and GPM, check the oil and fuel on a gas machine, and check the hoses and connections for leaks and wear. A cracked hose under pressure whips — replace it before you start, not after it fails.
Gear up. Safety glasses, closed shoes, gloves, and hearing protection for a gas machine. Long pants help. Never use a pressure washer barefoot or in sandals, and never let children operate one — the recoil and the jet are both stronger than they look.
Connect the water and purge the air. Hook up the garden hose, turn the water on, and squeeze the trigger with the machine off until water flows steadily. Starting the pump dry damages it in seconds. Then start the machine and pick your nozzle.
Test in a hidden spot. Start with the white 40-degree nozzle, twelve to eighteen inches from the surface, and test where damage would not show. If the dirt lifts, that nozzle is enough. Only step down to green or yellow if the test spot stays dirty — and step back the distance first.
Work in sweeping passes. Move the wand in steady, overlapping sweeps and keep it moving. Never hold the jet in one spot — that is how wood gets gouged and concrete gets etched. Keep the tip at a consistent distance and angle, about 45 degrees to the surface.
Work top-down on vertical surfaces. On siding and walls, start at the top so dirty water runs down over already-cleaned surface instead of over dry dirt. Rinse as you go so detergent and dirt do not dry in place.
Shut it down right. Turn the machine off, squeeze the trigger to release the pressure, disconnect the hoses, and drain them. For winter storage, run pump antifreeze through it or store it somewhere it cannot freeze — a frozen pump cracks, and that repair costs more than the washer.
Never point it at people or pets, and never wash your hands or feet with it — the jet cuts skin and can inject water under it, which needs a doctor. Do not pressure wash old paint on a pre-1978 house: it may be lead paint, and blasting it spreads lead dust. Skip asphalt shingles, soft wood, windows, and anything electrical. And never use one from a ladder: the recoil can throw you off balance, and a fall from a ladder with a live jet is a bad combination. The deck washing guide shows the same rules applied to wood, where the wrong nozzle leaves permanent scars.
Light cleaning — cars, patio furniture, siding — needs 1,300–1,600 PSI. Driveways and patios want 2,000–3,000 PSI with a yellow or green nozzle, which is also why a driveway wash pairs with repair: the concrete crack guide starts with cleaning the crack, and a pressure washer is the fastest way to do it. More PSI is not better — it is just more risk. Match the pressure to the surface, and let the nozzle and the distance do the work.
Yes. Even a home machine can cut skin and inject water under it, which can cause a serious infection. Never point it at people or pets, wear safety glasses, and treat the trigger with respect.
About 2,000–3,000 PSI with a 15- or 25-degree nozzle, kept at least a foot from the surface. Less than that leaves the stains; more than that etches the concrete.
Yes — apply it with the black soap nozzle at low pressure, let it sit a few minutes without drying, then rinse with a cleaning nozzle. Never run bleach through the machine unless the manual says it is safe.
Drain the water, run pump antifreeze through it, and store it where it cannot freeze. A frozen pump cracks, and that repair often costs more than a new machine.