Soft washing is how exterior walls should be cleaned in Corona: low pressure, the right solution, adequate dwell time, and a gentle rinse. It handles the organic growth and film that pressure cannot remove without damage, and on siding, painted surfaces, and stucco it is the only appropriate method.
Quick answer
Soft wash kills mildew, algae, and bacteria on exterior surfaces using low pressure (~500 PSI) and a biocidal cleaning solution.
The checklist is the same everywhere. What is on your glass is not. These are the conditions that actually shape this job in Corona. Each one is true here and false in plenty of other towns we serve.
Siding and painted surfaces have seams, laps, and fasteners. High pressure drives water past the surface into the assembly behind it, and it does not dry out from there. The result appears weeks or months later as blistering, staining, or a moisture problem that gets blamed on something else. Soft washing puts the work on the chemistry instead of the force, which cleans more thoroughly and leaves the wall intact. In Corona this is not a preference, it is the correct method.
Corona sits in or against the wildland urban interface, which means that in some years the deposit on the glass is not dust at all. Wildfire residue is a mix of fine carbon, alkaline ash, and condensed organic tars, and it behaves nothing like road film. The ash is caustic enough that letting it sit wet on glass etches it, the tar fraction is oily and smears rather than lifting, and the carbon is abrasive. Wiping a smoke-filmed window dry is the single fastest way to scratch it permanently. The right sequence is a flooded neutral-pH pass to carry the alkaline fraction off before anything with an edge touches the pane, then a separate solvent step for the tar, then the actual wash. It is genuinely a different job than a maintenance clean, we quote it as one, and we will tell you honestly when a pane has been etched past what cleaning can fix.
Corona pumps Corona's Temescal Basin wells blended with imported supply. That water has spent a long time moving through limestone-rich alluvium washed down out of the mountains, and it carries the calcium to prove it. Basin groundwater across this part of Southern California routinely runs twelve to eighteen grains per gallon. It is excellent water to drink and it is hard on glass, because every drop that dries on a window in this climate dries fast and completely, and what is left is mineral.
Low-pressure (~500 PSI) wash of every exterior surface: vinyl, fiber-cement (Hardie), stucco, painted wood, brick, masonry. Hardware-friendly: trim, gutters, soffit, and fascia all included.
Biocide application: sodium hypochlorite-based solution (the standard for soft-wash) that kills mildew, algae, lichen, and the black/green biological staining you see on shaded north-facing walls.
Plant and lawn protection, surfactant rinse during application, then full rinse-down at the end so nothing carries to your landscape.
Window pre-coat, we coat windows with plain water before the biocide so any drift doesn't streak the glass. We can also include the windows in the same trip, soft wash + window cleaning is a popular combo.
Optional add-ons: deck soft-wash, fence soft-wash, full-property bundle with driveway pressure wash.
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Plant covers, lawn pre-rinse, window pre-coat (plain water). Pets indoors. We tape any wall outlets or vents that need protection.
Top-down soft-wash with the biocidal solution. Dwell time 5-15 minutes, long enough to kill the biological staining, not long enough to damage paint.
Plain-water rinse from top to bottom to remove all solution and dead biological material. We watch for any streaking and re-apply if needed.
Walk-around to confirm clean coverage, plants and lawn rinsed, no overspray on neighbors. Before/after photos emailed.
Most Corona properties land between $565 and $1270 for this service. That band is derived from real Corona jobs, not a national average, which is why it differs from the number you would see on our page for a neighboring town. Here is how the job profiles break down:
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Historic core with early-century stock, original sash and divided lights. Hand work rather than equipment.
At the canyon mouth with the heaviest wind and grit load in the city, plus hillside access on some streets.
Master-planned hillside housing with great-room glass and association common landscape on recycled irrigation.
Newer production tracts with tile roofs, rooftop solar and construction dust from continuing development.
Established housing with mature landscaping and irrigation reaching ground-floor glass.
Homes and businesses near the freeway carrying oil-bound carbon that needs degreasing rather than washing.
See every neighborhood and the full local guide on our Corona window cleaning page.
Colorado's freeze-thaw cycle is brutal on siding and stucco, water gets into hairline cracks during the day and freezes at night, expanding the cracks and creating perfect conditions for algae and mildew to colonize. Annual soft-wash kills the colonization at the root.
North-facing walls get little direct sun and stay damp longer after snow or rain. That's where Front Range homes show the worst biological staining. Soft-wash is the only safe way to clean these surfaces without damaging the substrate.
Heavy hail (Boulder, Fort Collins, Loveland), hail-dimpled siding catches more biological growth in the dimples. Post-hail soft-wash slows the colonization significantly.
Pressure washing uses force; soft washing uses chemistry at low pressure. Hard surfaces like Corona driveways and walks take pressure fine. Walls, siding, painted surfaces, stucco, should never take it, because pressure drives water into the assembly where it causes damage that shows up later. Soft washing cleans those surfaces more thoroughly and does not put moisture where it does not belong.
A season to two years depending on exposure. North and shaded elevations regrow first because they hold moisture. The reason a soft wash lasts longer than a pressure wash is that the solution kills the organic growth rather than just removing what is visible, pressure leaves the biology behind and it comes back within months.
Soft wash uses low pressure (~500 PSI) and a biocidal cleaning solution. Pressure wash uses high pressure (~3,000 PSI) and mechanical force. Soft-wash is for siding, stucco, painted wood. Anything that high pressure could damage. Pressure wash is for concrete, brick, and other durable hard surfaces.
Most homes run $300–$800. A typical 2-story 2,000 sqft home is $400–$550. Bundling with window cleaning saves 10-15% on both. Larger homes (3,000+ sqft) or full-property bundles run higher.
No, when done properly. We pre-rinse plants and lawn before applying the biocide, use a surfactant during application, and do a full final rinse so nothing accumulates. Plants are the same green color when we leave as when we arrived.
It kills the current colonization completely. New algae will eventually colonize again, typically 12-18 months in Colorado, faster on north-facing walls in shaded yards. Annual or bi-annual soft wash keeps it at bay.
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