Pressure washer

What is a Pressure Washer?

A pressure washer is a machine that pressurizes water and forces it through a nozzle to clean surfaces. Unlike a standard garden hose, the concentrated spray can break the bond between grime and the surface, speeding up cleaning jobs dramatically. Two numbers define performance:

• PSI (pounds per square inch): How much pressure the machine produces; higher PSI can remove tougher contaminants but also increases the risk of damage.
• GPM (gallons per minute): How much water flows; more GPM helps rinse debris faster.

Together, PSI and GPM determine cleaning power. The unit uses a pump (driven by an electric motor or gasoline engine), a high-pressure hose, and a spray gun with quick‑connect nozzles that change the spray angle and intensity.

Common DIY and Home Uses

Pressure washers save time on many outdoor chores:

• Driveways and sidewalks: Remove dirt, tire marks, and light oil stains.
• Decks and fences: Lift mildew and weathered fibers before staining or sealing.
• House siding (vinyl, fiber cement, brick): Wash away algae and cobwebs. Keep the spray at a safe angle to avoid forcing water behind siding.
• Patios and pavers: Clear moss and joint growth; follow up by re-sanding joints if needed.
• Outdoor furniture and grills: Clean plastic, metal, and some woods; use lower pressure.
• Vehicles, boats, lawn equipment: Soap and rinse efficiently with gentle settings.
• Prep for painting: Strip loose, flaking paint and clean surfaces prior to primer.

Types and Variations

• Electric vs. Gas:

  • Electric (1,300–2,000 PSI, ~1.2–1.8 GPM): Quieter, low maintenance, great for small jobs and siding cleaning from ground level. Require a GFCI outlet and extension cord rated for outdoor use.
  • Gas (2,500–4,000+ PSI, ~2.3–4.0+ GPM): More power and flow for large areas like long driveways or prepping rough surfaces. Louder, heavier, and require fuel and engine maintenance.

• Cold vs. Hot Water:

  • Cold-water units: Most homeowner models; handle general dirt, mildew, and mud.
  • Hot-water units: Heat improves removal of grease and oil; typically commercial.

• Pump Types:

  • Wobble/axial cam: Common on homeowner models; compact with limited serviceability.
  • Triplex: Found on higher-end gas units; longer life, serviceable, costlier.

• Nozzles (color-coded):

  • 0° red: Pinpoint, very aggressive—avoid for most surfaces.
  • 15° yellow: Heavy cleaning (concrete, metal) at safe distance.
  • 25° green: General cleaning (decks, patio furniture).
  • 40° white: Gentle rinsing (vehicles, windows with care).
  • Black soap nozzle: Low-pressure for applying detergents.

• Useful accessories: Surface cleaners (rotary head for even driveway cleaning), turbo/rotary nozzles (spinning point stream for faster concrete cleaning), foam cannons, telescoping wands for upper siding, and inline filters to protect the pump.

How to Choose the Right Pressure Washer

Match the machine to your tasks and water supply:

• Light-duty (1,300–1,900 PSI; 1.2–1.6 GPM): Cars, patio furniture, small patios, vinyl siding maintenance.
• Medium-duty (2,000–2,800 PSI; 1.8–2.5 GPM): Decks, fences, larger patios, routine driveway cleaning.
• Heavy-duty (2,900–3,300+ PSI; 2.5–3.5+ GPM): Stained concrete, paint prep, extensive hardscape cleaning.

Tips:
- Consider both PSI and GPM. Higher GPM often speeds up rinsing more than extra PSI alone.
- Check your water supply can meet the GPM demand; running a pump starved of water can damage it.
- For frequent driveway work, a surface cleaner attachment can cut time and streaks.
- If you’ll clean second-story siding, plan for a telescoping wand or a low-pressure soap application from the ground—skip the ladder.

Safe Use and Good Technique

• Protective gear: Wear safety glasses, closed-toe shoes, and hearing protection for gas units. Gloves help with grip.
• Test first: Start with a wider nozzle (25° or 40°) on an inconspicuous spot and increase pressure only if needed.
• Maintain distance: Begin 18–24 inches from the surface; move closer gradually to find the minimum pressure that works.
• Spray angle: Keep the wand at about 45° to the surface to lift dirt rather than drill into it.
• Work pattern: Overlap passes, moving steadily to avoid striping. On vertical surfaces, wash from the bottom up with soap, then rinse from the top down.
• Detergents: Use cleaners labeled for pressure washers. Apply with the black soap nozzle, let dwell a few minutes, keep surfaces wet, then rinse thoroughly. Avoid running chlorine bleach through the pump; apply it with a garden pump sprayer if a job requires it, and rinse gear afterward.
• Mind the environment: Pre-wet plants, cover delicate landscaping, and divert runoff from ponds. Follow local rules for wastewater.
• Electrical safety: Keep water away from outlets, light fixtures, and service panels. Electric units should plug into GFCI-protected outlets.
• Ladders: Avoid using a pressure washer from a ladder—the kickback can cause a fall. Use extensions or stand-off stabilizers.

Maintenance and Storage

• Flush soap: After using detergents, run clean water through the system for a minute.
• Check and clean nozzles: A clogged nozzle raises pump pressure; clear with a nozzle cleaning tool or fine wire.
• Inspect hoses and O-rings: Replace cracked hoses and worn seals to prevent leaks and bursts.
• Pump care: Some pumps are sealed; serviceable pumps may require periodic oil changes (follow the manual).
• Water filter: Use an inlet screen or filter to keep grit out of the pump.
• Winterize: In freezing climates, run pump saver/antifreeze through the unit or store in a heated space. Never let water sit and freeze in the pump.

Common Mistakes to Avoid

• Using a 0° nozzle on paint, wood, siding, or vehicles—this can gouge or shatter materials.
• Too much pressure on wood: Use 25° or 40° nozzles and moderate PSI to avoid furring and raised grain.
• Blasting under siding or into vents: Can trap water and create mold issues.
• Spraying windows, seals, or soft stone at close range: May crack glass or erode mortar.
• Letting the unit idle too long without spraying: Heat builds in bypass and can damage the pump.
• Running dry or with a kinked hose: Starves the pump and shortens its life.
• Fueling a hot gas unit or using gas units indoors: Fire risk and carbon monoxide hazard.

Related Terms

• PSI (pounds per square inch): Pressure rating.
• GPM (gallons per minute): Water flow rate.
• Surface cleaner: Spinning, enclosed dual-nozzle head for even flat-surface cleaning.
• Turbo/rotary nozzle: Rotating point stream for faster concrete work.
• Downstream injector: Draws detergent after the pump for safer chemical use.
• GFCI: Ground-fault protection for electric models.

Practical Examples

• Driveway cleaning: A 3,000 PSI, 2.5 GPM gas unit with a 15° nozzle or a 15–16 inch surface cleaner can clean a two-car driveway in under two hours. Pretreat oil stains with a degreaser, keep the head moving, and rinse thoroughly.
• Vinyl siding wash: An electric 1,600–2,000 PSI unit with a soap nozzle to apply house wash from the ground, followed by a 25° or 40° rinse. Work in sections, avoid spraying up into laps, and protect plants.
• Deck prep for stain: Use 1,200–1,800 PSI with a 25° or 40° nozzle, apply wood cleaner, let dwell, then rinse along the grain from 12–18 inches. After drying, brighten if needed and sand high fibers before finishing.
• Vehicle wash: Stick to 1,200–1,900 PSI with a 40° nozzle or foam cannon, maintain distance (18–24 inches), avoid direct hits to badges and seals, and use a touch-safe car shampoo.

Used thoughtfully, a pressure washer speeds up outdoor cleaning and surface prep while helping you avoid damage and rework.