Pressure Washing
Exterior Cleaning · exterior-cleaning
PSI selection, nozzle choice, and spray distance determine whether you restore a surface or destroy it. Concrete handles 3,000–4,000 PSI; wood tops out at 1,500. Always test an inconspicuous area first, start at lower pressure, and increase only if the surface demands it.
PSI Selection by Surface
Match PSI to the material — no exceptions. Concrete driveways and sidewalks take 3,000–4,000 PSI for oil stains and embedded grime. Wood decks and fences stay at 1,200–1,500 PSI to prevent fiber damage and splintering. Vinyl siding cleans at 1,300–1,600 PSI; push higher and you crack panels or force water behind them. Brick and masonry handle 2,000–3,000 PSI for mortar stains and efflorescence. Asphalt sits at 2,500–3,000 PSI — enough to clean without disturbing aggregate. Painted surfaces get 1,200–1,500 PSI maximum to preserve paint adhesion. Older or deteriorated surfaces need even lower pressure; adjust based on condition, not just material type.
Nozzle Tips and Color Codes
Nozzle tips are color-coded by spray angle. Narrower angles concentrate more force. The 0° red tip fires a pencil jet — use it only on tough stains on hard concrete, never on wood or siding. The 15° yellow tip delivers a narrow fan for stripping and heavy-duty concrete work. The 25° green tip is your workhorse — medium fan, general-purpose cleaning, and the tip you reach for most often. The 40° white tip spreads a wide fan for rinsing, delicate surfaces, and painted wood. The 65° black tip runs extra-wide at lowest pressure, designed exclusively for applying detergent through the downstream injector. Turbo/rotary nozzles combine 0° power with circular motion for aggressive cleaning on hardscape. Never point any nozzle at people, animals, windows, or electrical components.
PSI & Nozzle Selection by Surface
Quick-reference table for selecting the right PSI and nozzle tip by surface. Test in an inconspicuous area before committing to full coverage.
PSI & Nozzle Selection by Surface
| Surface | PSI Range | Nozzle Tip | Distance | Notes |
|---|---|---|---|---|
| Concrete Driveway | 3,000–4,000 | 15° Yellow or 25° Green | 6–8 inches | Use surface cleaner attachment for even results |
| Wood Deck | 1,200–1,500 | 25° Green or 40° White | 12–18 inches | Go with the grain; never hold in one spot |
| Vinyl Siding | 1,300–1,600 | 25° Green or 40° White | 12–18 inches | Spray downward to prevent water behind panels |
| Brick | 2,000–3,000 | 15° Yellow or 25° Green | 8–12 inches | Avoid damaged mortar joints; re-point first if needed |
| Pavers | 2,500–3,000 | 25° Green | 8–12 inches | Re-sand joints after washing; apply sealer when dry |
| Stucco | 800–1,200 | 40° White | 18–24 inches | Soft wash preferred; pressure can crack stucco |
| Painted Surface | 1,200–1,500 | 40° White | 18–24 inches | Test adhesion first; avoid chipping loose paint |
| Aluminum Siding | 1,500–2,000 | 25° Green or 40° White | 12–18 inches | Watch for dents; oxidized aluminum needs chemical treatment |
| Wood Fence | 1,200–1,500 | 25° Green | 12–18 inches | Follow the grain; feather edges to avoid lap marks |
| Concrete Block | 2,500–3,500 | 15° Yellow or 25° Green | 6–10 inches | Seal after cleaning to prevent future staining |
Nozzle Tip Color Code Reference
Universal color coding for pressure washer nozzle tips. Narrower angles deliver more concentrated force — select the correct tip to prevent surface damage and maximize cleaning efficiency.
Nozzle Tip Color Code
| Color | Degree | Spray Pattern | Use For |
|---|---|---|---|
| Red | 0° | Pencil jet — extremely concentrated | Stubborn stains on hard concrete only; rust and tar removal |
| Yellow | 15° | Narrow fan — high impact | Heavy-duty stripping; concrete prep; paint removal |
| Green | 25° | Medium fan — general purpose | Most common tip; everyday cleaning of driveways, siding, decks |
| White | 40° | Wide fan — gentle coverage | Rinsing; delicate surfaces; windows; painted wood |
| Black | 65° | Extra-wide fan — lowest pressure | Soap and chemical application only; downstream injector use |
Chemical Application and Technique
Many pressure washing jobs require chemical pre-treatment. Apply chemicals through a downstream injector — never run them through the pump directly. Work vertical surfaces from bottom to top to prevent streaking, allow 5–10 minutes of dwell time, and never let the solution dry on the surface. Rinse from top to bottom in overlapping passes, maintaining a consistent 18-inch distance and 4–6 inch overlap between passes to avoid striping. Hold the wand at 15–30° from perpendicular for even cleaning.
- Pre-wet all plants and landscaping within 10 feet before applying chemicals
- Cover delicate plants with plastic sheeting near garden beds
- Rinse all adjacent surfaces after completing the job
Checklists
Pressure Washing Job Checklist
- Inspect surface and identify material type
- Select appropriate PSI and nozzle tip
- Connect water supply and verify adequate flow (minimum 2.5 GPM)
- Pre-wet surrounding landscaping and cover sensitive plants
- Apply chemical pre-treatment if needed (bottom to top)
- Allow appropriate dwell time (5–10 minutes)
- Rinse surface using overlapping passes (top to bottom)
- Inspect finished work for missed spots or streaks
- Rinse surrounding areas to remove chemical overspray
- Disconnect equipment and properly coil hoses