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Exterior Mold & Mildew Removal for Wood Siding in California

Soft wash for wood siding. Killing and removing mold, mildew and algae from siding, decks, walkways and fences, with treatment that slows regrowth. Typical cost $250-$700.

Grime, mildew and stains build up a little at a time until one day the outside of your property looks years older. Exterior Mold & Mildew Removal for Wood Siding in California brings it back, usually in a single visit. On wood siding, the method we use is soft wash.

How we clean it

Soft washCleaning method
Soft wash, typically under 500 PSI; up to about 1,000 PSI with a wide tip for bare wood prepPressure

Cleaning solution: A mild house-wash mix; an oxygen-based cleaner when the wood will be stained.

Cleaning wood siding safely

Painted and stained wood siding grows mildew and loses its finish faster on the shaded and weather-facing sides. A soft wash cleans it without raising the grain, and is the usual first step before repainting or restaining.

Avoid: High pressure that raises fibers, gouges the wood or strips sound paint unevenly.

How often: Every 1-2 years, and before every repaint.

When to book exterior mold & mildew removal for wood siding

  • Black, green or gray spots and film
  • Slippery walkways and decks
  • Musty smell near shaded walls
  • Growth that returns soon after rinsing

What causes the dirt and stains

  • Shade, humidity and poor air flow
  • Organic debris and pollen
  • Surfaces that stay damp after rain or sprinklers

Safe steps for homeowners

  • Improve sun and air flow by trimming plants
  • Keep gutters and sprinklers from soaking walls
  • Clean small areas with an outdoor mildew cleaner, following the label

Not sure what you're looking at? The free stain identifier and safe pressure guide explain each stain and surface.

Why more pressure isn’t better

  • Blasting growth off without killing it, so it grows back fast
  • Mixing cleaning chemicals, which can release toxic gas
  • Damaging plants with runoff

What happens on the day

  1. Identify surfaces and growth
  2. Protect plants and fixtures
  3. Apply a solution that kills the growth
  4. Rinse at low pressure
  5. Post-treat where helpful to slow regrowth

This service is for outdoor surfaces. Mold inside the home, in attics or in wall cavities needs a mold remediation specialist, not a pressure washing company.

How much does exterior mold & mildew removal for wood siding cost?

$250-$700Typical range for typical exterior growth on a home
2-4 hoursTypical time on site
Every 1-2 years in humid or shaded areasRecommended frequency

What moves the price:

  • Size: square footage of siding, roof or flatwork
  • Condition: heavy growth, old stains and peeling finishes take longer
  • Access: number of stories, roof pitch, slopes and how close we can park
  • Add-ons: sealing, gutter brightening and other services done in the same trip

These are typical U.S. ranges, not a quote. You get an exact price before any work starts. For a quick estimate, try the pressure washing cost calculator.

Other services for wood siding

Serving California and nearby towns

In California, stucco and siding mostly collect dust, cobwebs and sprinkler spots, while shaded walls can grow mildew after winter rains. A soft wash handles both without etching stucco.

Near the coast, salt air leaves a film on siding, windows, screens and railings that dulls finishes and speeds up corrosion on metal. Regular rinsing and washing help protect them.

Much of California has hard water. Sprinklers and misters leave white mineral spots on walls, windows, fences and pool tile, and those spots need a mineral-safe cleaner, not more pressure.

Some cities in California limit outdoor water use, including washing hard surfaces with a hose, especially during drought declarations. Pressure washers use far less water than an open garden hose, but rules vary, so it's worth checking your city's current restrictions. Wash water should also be kept out of storm drains.

We cover 841 cities and towns across California. Find exterior mold & mildew removal for wood siding in your city:

Exterior Mold & Mildew Removal for Wood Siding: frequently asked questions

How much does exterior mold & mildew removal for wood siding cost in California?

Exterior Mold & Mildew Removal for Wood Siding typically costs $250-$700 for typical exterior growth on a home, and usually takes 2-4 hours. The exact price depends on the size and condition, and you get it before any work starts. Call (555) 010-0000 for a free quote.

Do you use high pressure for exterior mold & mildew removal for wood siding?

For wood siding: soft wash, typically under 500 PSI; up to about 1,000 PSI with a wide tip for bare wood prep. What we avoid: high pressure that raises fibers, gouges the wood or strips sound paint unevenly. The cleaning solution does most of the work, followed by a gentle rinse.

Is exterior mold & mildew removal for wood siding safe for my plants and pets?

We pre-wet plants and lawns, keep cleaning solutions diluted to what the surface needs, and rinse landscaping again when we finish. Keep pets and children inside until surfaces are rinsed and dry.

How often should I schedule exterior mold & mildew removal for wood siding?

Every 1-2 years, and before every repaint. Shade, nearby trees, humidity and heavy traffic mean more frequent cleaning; sunny, dry spots can go longer. Our free cleaning frequency tool gives a recommendation for your climate.

What if it rains on the day?

Light rain doesn't stop most washing, but heavy rain, high wind, lightning and freezing temperatures do. If the weather isn't right, we reschedule at no charge. Our work is backed by a satisfaction guarantee.

More services

Popular Exterior Cleaning Services in California

Pool Deck Cleaning for Exposed Aggregate

Moderate-pressure wash. Exposed aggregate concrete has stones showing at the surface.

Typical $200-$500

Oil Stain Removal for Exposed Aggregate

Moderate-pressure wash. Exposed aggregate concrete has stones showing at the surface.

Typical $100-$300

House Washing for Aluminum Siding

Soft wash. Older aluminum siding often has a chalky, oxidized finish.

Typical $300-$700

Fence Cleaning for Cedar

Low-pressure wash. Cedar decks and fences turn silver-gray as the surface weathers.

Typical $200-$600

Rust Stain Removal for Stucco

Soft wash. Traditional stucco is porous and holds moisture, which is why it streaks green and black in humid and shaded spots.

Typical $150-$500

Soft Washing for Wood Siding

Soft wash. Painted and stained wood siding grows mildew and loses its finish faster on the shaded and weather-facing sides.

Typical $300-$800

House Washing for Log Homes

Low-pressure wash. Log homes need regular cleaning to keep mildew and insects from settling into checks and cracks, and the logs must be clean and dry before a new stain goes on.

Typical $300-$700

Pressure Washing for Brick

Low-pressure wash. Brick is tough, but the mortar joints are softer than the brick itself, and older soft-fired brick can pit.

Typical $150-$600

Concrete Sealing for Concrete

Pressure wash with a surface cleaner. Plain broom-finish concrete is the surface pressure washing is made for.

Typical $400-$1,200

Parking Lot & Garage Cleaning

Cleaning parking garages, lots and loading areas to remove oil, grime, gum and litter.

Typical $500-$3,000

Efflorescence Removal for Brick

Low-pressure wash. Brick is tough, but the mortar joints are softer than the brick itself, and older soft-fired brick can pit.

Typical $200-$600

Fence Cleaning for Vinyl Fencing

Soft wash. White vinyl fencing shows green algae, mildew and sprinkler stains quickly.

Typical $200-$600

Ready for a cleaner home or business?

Get a free pressure washing quote in California. Tell us what needs cleaning and we'll give you a price and the next available date.

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