TL;DR
Most residential siding should be soft washed rather than pressure washed. Soft washing uses low pressure and a cleaning solution with dwell time to kill and release organic growth, which is what actually discolors a house. High pressure on siding drives water behind the panels, strips paint, and damages soft materials -- and it leaves growth to return within months because it never killed the root.
Pressure Versus Soft Wash, and Why It Matters
The green and black staining on a shaded wall is not dirt. It is algae, mildew, and lichen growing on the surface.
Pressure knocks the visible layer off and leaves the organism behind, so the staining returns quickly. A cleaning solution with dwell time kills it, which is why soft-washed houses stay clean far longer than pressure-washed ones.
Soft washing means low pressure -- roughly garden-hose level at the surface -- delivered through a wide fan or a dedicated soft-wash setup, with a detergent and sodium hypochlorite solution doing the work chemically. Rinse follows, also at low pressure.
That distinction is the whole ballgame in house washing. A quote that says "pressure washing" for a house is worth a follow-up question about actual pressure and method.
What Does a House Washing Service Cover?
It typically covers the siding faces, soffits and fascia, gutters exterior, trim, downspouts, exterior light fixtures, and often the front door surround and porch ceiling. Windows are rinsed but usually not cleaned to a finished standard. Roof cleaning, deck restoration, and any repair are separate services.
Some scopes include or exclude the underside of eaves, which is where spider webs and mud nests live, so it is worth naming explicitly.
Material by Material
This is where the method has to change, and where damage happens when it does not.
Vinyl siding. Tolerates a moderate approach but has overlapping seams that face upward. Water directed upward at the seam goes behind the panel and into the wall assembly. Vinyl is washed with the lap, angled slightly downward, never up. Older vinyl becomes brittle and chalky in sun exposure, and aggressive work makes chalking worse.
Painted wood and fiber cement. Soft wash only. Pressure lifts paint, raises wood grain, and forces water into end grain and joints. Fiber cement holds paint well but its joints and butt seams admit water.
Stucco and EIFS. Very sensitive. Stucco is porous and pressure erodes the finish coat, while EIFS is a foam-backed system where forced water causes serious hidden damage. These need low pressure and appropriate chemistry, and some providers decline EIFS entirely.
Brick and stone. Durable faces, vulnerable mortar. High pressure erodes mortar joints, particularly on older lime-mortar buildings, and repointing is expensive. Low pressure and chemistry are the correct approach.
Aluminum siding. Chalks heavily with age. Washing removes the chalk layer, which can leave uneven color, and the honest conversation is that a chalked aluminum house may need painting rather than washing.
Cedar shake and shingle. Soft wash only. Pressure erodes the soft summer wood between growth rings and permanently furs the surface.
When Siding Should Not Be Washed at All
Several conditions mean stop rather than proceed.
Failing paint. If paint is peeling or flaking, washing accelerates it and drives water into bare substrate. That house needs a paint assessment, not a wash -- though a controlled wash is often part of paint prep, performed by the painter.
Damaged or missing siding. Gaps, cracked panels, and open butt joints let water into the wall. Repair first.
Rotted wood. Soft trim, rotted sills, and spongy fascia are carpentry, and washing them makes it worse.
Homes built before 1978 with deteriorating paint. Lead-based paint is a real concern in older housing, and disturbing it -- including by washing -- has specific rules. This is not a cleaning decision. A lead-safe certified contractor should evaluate it.
Active pest nests. Wasp and hornet nests under eaves go to pest control before anyone puts a wand near them.
Visible mold inside the home on the same wall. That points to a moisture path through the wall assembly, which is a building envelope problem for a contractor, not a surface to be washed.
Plants, Runoff, and Protection
House washing solutions are hard on landscaping, and protecting plants is part of a competent job.
Plants get pre-wetted before the wash, kept wet during it, and rinsed afterward. Pre-wetting is what dilutes any solution that lands on foliage. Some crews cover sensitive plantings entirely.
Electrical fixtures, outlets, and any opening in the wall get avoided or protected. Attic and crawlspace vents are entry points for water. Window and door seals on older homes leak under direct spray.
Runoff should be directed away from storm drains where practical and away from any water feature or vegetable garden.
Ask a provider what they do to protect landscaping. It is a fast test of how carefully they work.
Sequence and Timing
Exterior work runs top down, always.
Gutters first, so debris and flush water do not land on clean siding. Then the house wash. Then windows, because the wash rinses across glass. Then ground-level hardscape like driveway pressure washing, which catches everything that ran down. Wood surfaces such as a deck cleaning service fit into the same day but use their own low-pressure method.
Timing is mostly about season and weather. Late spring through early autumn is the working window in most climates. Avoid washing in freezing conditions, in high wind that carries solution onto neighbors and plants, or in direct hot sun where solution dries before it can work.
Frequency depends on exposure. North-facing walls and anything under tree cover grow organic staining fastest and often need annual attention. Sunny walls can go two or three years. Coastal properties dealing with salt deal with a different problem and often rinse more frequently.
The full order of operations is set out in the exterior surface cleaning guide, and what a dedicated crew covers is on the pressure washing services page.
What to Ask Before Booking
Six questions cover most of the risk.
What pressure and method will be used on my specific siding material. Whether soft washing is included or whether this is a pressure-only service. How landscaping is protected. What surfaces are in scope -- soffits, fascia, gutters exterior, trim, light fixtures. Whether they carry liability and workers compensation insurance. And what happens if damaged siding, failing paint, or rot is found once work starts.
A provider who answers those clearly and adjusts the method to the material is doing this properly. One who has a single pressure setting for every house is the one to avoid.
FAQ
Should siding be pressure washed or soft washed?
Soft washed, in most cases. The staining on siding is usually algae and mildew growth, which a cleaning solution kills and pressure merely knocks off temporarily. Soft washing also avoids driving water behind panels and into the wall assembly, which is the main risk of high pressure on any siding.
Can pressure washing damage vinyl siding?
Yes. Vinyl panels overlap with upward-facing seams, so water aimed upward goes behind them into the wall. High pressure can also crack older brittle panels and worsen surface chalking. Vinyl is washed with the lap, angled slightly downward, at low pressure with chemistry doing the work.
Why does the green staining come back so quickly after washing?
Because pressure removed the visible growth without killing the organism. Algae and mildew regrow from what remains in the surface. A soft wash using an appropriate solution with dwell time kills the growth, which is why properly soft-washed houses stay clean for far longer.
Is it safe to wash a house with peeling paint?
No. Washing accelerates paint failure and drives water into exposed substrate. A house with peeling paint needs a paint assessment first, and controlled washing is usually done by the painter as surface prep. On homes built before 1978, deteriorating paint may contain lead and needs a lead-safe certified contractor.
How often should a house be washed?
North-facing walls and walls under tree cover often need annual attention because organic growth returns fastest there. Sunny, exposed walls can go two to three years. Rather than a fixed schedule, watch for the green or black film returning and book when it becomes visible.
Will house washing damage my plants?
Not if the crew protects them. Pre-wetting foliage before the wash, keeping it wet during, and rinsing afterward dilutes anything that lands. Sensitive plantings are sometimes covered outright. Asking how landscaping is protected is one of the better questions to put to any provider.
Method should match material, so a look at your siding is what produces an accurate plan. Otesse is local, background-checks its crews, prices upfront with no hidden fees, and books online -- see home cleaning services or get a quote. Every property is different, so the real number depends on size, condition, and what you want covered.