Ask ten contractors how often a house should be pressure washed and you will get ten answers. Most of them are written for dry inland climates and simply do not apply on the Humboldt coast, where fog rolls in most mornings and rainfall regularly clears sixty inches a year.
Why Humboldt is different
Algae, moss, and lichen need three things to thrive: moisture, shade, and a surface to hold on to. Between Eureka, Arcata, and the coast road out to Trinidad, we have all three in abundance for most of the year. A north-facing wall in Bayside can go visibly green in a single winter.
That growth is not just cosmetic. Moss holds water against timber and concrete, which accelerates rot, spalling, and paint failure. Left alone for a few seasons it turns a cleaning job into a repair job.
A realistic schedule by surface
Different surfaces weather at very different rates. Rather than washing everything on the same day every year, it is cheaper and more effective to stagger the work.
- Driveways and walkways — once a year, ideally late spring once the wet season has passed.
- Siding and exterior walls — every 12 to 18 months, sooner on shaded north elevations.
- Decks and stairs — annually, and immediately if the surface has gone slick underfoot.
- Fences — every 1 to 2 years, or right before you plan to stain or seal.
- Trash enclosures and commercial pads — monthly to quarterly, depending on volume.
Pressure is not the answer to everything
The single most common mistake we are called out to fix is somebody attacking painted siding with a 3,000 PSI wand. Water gets forced behind the cladding, the paint lifts, and the repair costs far more than the wash ever would have.
Painted and clad surfaces should be soft washed: low pressure, a cleaning solution that kills the growth at the root, and a gentle rinse from the top down. Concrete, masonry, and pavers can take real pressure, and benefit from a rotary surface cleaner that leaves an even finish instead of wand stripes.
The best time of year to book
Late spring is the sweet spot for most exterior work in Humboldt County. The winter growth is at its peak and clearly visible, surfaces get a chance to dry properly, and a clean surface heading into summer stays clean longer.
Autumn is the second window — particularly for driveways and walkways, where a clean, moss-free surface is genuinely safer to walk on once the rain returns.
If you are not sure where your property sits on this schedule, we are happy to take a look. CH Cleaning provides free, no-pressure estimates across Eureka, Arcata, Fortuna, McKinleyville, and the rest of Humboldt County.