Pressure Washing Season Is Here: What Every Bellevue & Seattle Homeowner Should Know

If you have lived in the Seattle area for even one winter, you know what happens to outdoor surfaces. The combination of constant moisture, limited sunlight, and mild temperatures creates perfect growing conditions for moss, algae, and mildew on driveways, sidewalks, patios, decks, and siding. By late winter, many Eastside homes look like they are being slowly consumed by green growth. Pressure washing is the solution, but timing and technique matter.

When to Pressure Wash in the Pacific Northwest

The ideal window for pressure washing in our region is late February through May, when the worst of the winter rain is subsiding but before the summer dry season. This timing allows you to remove all the winter buildup and start the season with clean surfaces. Waiting too long means the moss and algae have more time to establish roots in concrete pores and wood grain, making them harder to remove. Some homeowners also schedule a second wash in early fall to address summer pollen and prepare for the rainy season ahead.

What Should Be Pressure Washed

The most common surfaces that benefit from pressure washing include concrete driveways and walkways, which develop dark stains and green moss growth over winter. Patios and outdoor entertaining areas that have been neglected all winter come alive after a good pressure wash. Wooden decks and fences can be pressure washed, but require lower pressure settings and appropriate technique to avoid damage. Home siding — particularly in shaded areas on the north side of the house — often develops green algae that makes even a new home look neglected. Garage floors, retaining walls, and even outdoor furniture can all benefit from professional pressure washing.

Common Mistakes to Avoid

The biggest mistake homeowners make is using too much pressure on the wrong surfaces. High-pressure settings can damage wood decking, strip paint, etch concrete, and even break windows. Different surfaces require different pressure levels, nozzle types, and techniques. Using the wrong cleaning solution is another common error — bleach-based solutions can kill surrounding plants and contaminate soil, while the wrong detergent can leave streaks or residue. Always test pressure and technique in an inconspicuous area first, and never point a pressure washer at windows, electrical fixtures, or areas where water could penetrate behind siding.

DIY vs. Professional Pressure Washing

Renting a consumer pressure washer from a hardware store is an option, but there are significant advantages to hiring a professional. Professional equipment delivers consistent, calibrated pressure that consumer models cannot match. Experienced operators know exactly which pressure setting, nozzle, and cleaning solution to use for each surface, avoiding the damage that well-intentioned DIY efforts sometimes cause. Professional pressure washing also typically includes surface treatment that slows the regrowth of moss and algae, extending the time between cleanings. For large driveways, two-story siding, or delicate surfaces like painted wood, professional service is almost always the better investment.

What to Expect From a Professional Pressure Wash

When our team arrives for a pressure washing job, we start by assessing all the surfaces to be cleaned and identifying any areas that need special care. We protect plants, outdoor furniture, and fixtures before beginning. We use eco-friendly cleaning solutions that are effective against moss and algae but safe for your landscaping and the environment. The actual washing process works systematically across each surface, ensuring even coverage and thorough cleaning. After washing, we inspect every area and address any spots that need additional attention. Most residential pressure washing jobs are completed in half a day, and the transformation is dramatic.