How to Power Wash Your Home's Exterior
Remove years of dirt, mold, and mildew from your home's siding, driveway, and deck in 2-3 hours. This beginner guide covers machine setup, detergent use, and technique for a like-new finish.
Repair & Refinish Team
Published May 10, 2025 · Updated October 25, 2025
What You'll Need
- Pressure washer (electric 1,500-2,000 PSI)
- Garden hose with adequate length
- 25-degree and 40-degree spray tips
- Extension wand (for second story)
- Safety glasses
- Rubber boots
- Pressure washer detergent (house wash formula)
- Outdoor bleach-based cleaner (for mold/mildew)
- Plastic sheeting (to cover plants and outlets)
Cost Estimate
Budget
$30
Mid-Range
$75
Premium
$150
Professional power washing costs $200-$600 for a house. DIY detergent and rental cost $30-$100 (or buy a washer for $150-$300).
Step-by-Step Instructions
Prepare the Area
Step 1 of 7Close all windows and doors. Cover electrical outlets, light fixtures, and doorbell with plastic and tape. Move outdoor furniture and grills away from the house. Cover delicate plants with plastic sheeting — pressure washer detergent can burn foliage. Sweep loose debris from the areas you'll wash.
Set Up the Pressure Washer
Step 2 of 7Connect the garden hose to the washer's water inlet. Connect the high-pressure hose to the spray wand. Turn on the water supply fully. Squeeze the trigger to purge air from the system (water will flow weakly until the air is out). Start the washer and let it run for 30 seconds before spraying. Attach the 40-degree (white) tip for applying detergent.
Never use a 0-degree (red) tip on siding. It concentrates the water stream enough to cut through vinyl, gouge wood, or strip paint. Use 25-degree for rinsing and 40-degree for detergent.
Apply Detergent From Bottom to Top
Step 3 of 7Switch to the detergent tip or soap nozzle. Apply house-wash detergent starting at the bottom of the wall and working upward. This prevents dirty detergent from running down dry siding and leaving streaks. Work in sections of about 10x10 feet. Let the detergent dwell for 5-10 minutes (don't let it dry). The detergent breaks down mold, mildew, and dirt so the rinse can remove them.
Rinse From Top to Bottom
Step 4 of 7Switch to the 25-degree (green) tip. Starting at the top, rinse the detergent and loosened dirt downward with overlapping passes. Keep the nozzle at least 12 inches from the surface and angle the spray slightly downward to avoid driving water behind the siding. Work in smooth, sweeping horizontal passes. The dirty water cascades down, carrying grime off the wall.
Spray at a downward angle (never upward) on lap siding. Spraying upward forces water behind the siding and into the wall cavity.
Address Stubborn Mold and Stains
Step 5 of 7For areas with heavy mold, mildew, or algae (common on north-facing walls), apply a bleach-based outdoor cleaner directly and let it sit for 15 minutes. Scrub stubborn spots with a soft-bristle brush. Re-rinse with the pressure washer. For rust stains, use an oxalic acid-based cleaner. For oil stains on concrete, use a degreaser and let it soak before pressure washing.
Wash the Driveway and Walkways
Step 6 of 7For concrete, switch to the 25-degree or 15-degree (yellow) tip and work about 6 inches from the surface. Use overlapping passes in a consistent pattern to avoid striping (visible clean/dirty lines). A surface cleaner attachment ($30-$60) spins two jets under a housing for faster, more even concrete cleaning. For heavy stains, apply degreaser first and let it dwell before washing.
Clean Up and Maintain
Step 7 of 7Disconnect the washer, drain the hoses, and store the equipment. Remove plastic covering from plants and outlets. Check that no water was driven behind siding or into windows. Rinse any plants that were accidentally sprayed with detergent. To maintain the clean look, consider applying a mold-resistant siding wash annually.
Recommended Products
Best-selling consumer electric pressure washer. Dual detergent tanks, 5 quick-connect tips, 14.5-amp motor. Ideal for siding, decks, driveways, and vehicles.
Pressure washer detergent that removes mold, mildew, algae, and dirt. Safe for vinyl, stucco, brick, and wood. One gallon makes 10 gallons of solution.
Spinning dual-jet surface cleaner for driveways and patios. Eliminates striping. Cleans 3x faster than a wand. Fits any pressure washer with a standard quick-connect tip.
Affiliate Disclosure: We earn a small commission when you buy through our links at no extra cost to you.
Tips & Warnings
- Start with the lowest effective pressure and increase only if needed. You can always add more pressure, but you can't undo damage.
- A surface cleaner attachment for concrete is worth the $30-$60 investment. It cleans 3x faster than a wand and eliminates striping.
- Schedule power washing in spring — it removes winter grime and prepares surfaces for staining, painting, or sealing.
- Never power wash your roof. High pressure damages shingles and voids the warranty. Use a low-pressure chemical wash for roofs.
- Never aim a pressure washer at a person, pet, or window. The water stream at close range can cause serious injury and break glass.
- Do not spray upward under lap siding. Water driven behind siding causes rot and mold in the wall cavity.
- Keep the nozzle at least 6-12 inches from vinyl siding. Too close will leave marks, crack the vinyl, or force water behind the panels.
- Cover electrical outlets and don't spray directly at them. Water and electricity are a deadly combination.
Frequently Asked Questions
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