Chemistry cleans the villa. Pressure just punishes it.
Wellington's combination of harbour salt, northerly wind and damp south-facing walls grows mould and grime faster than most NZ cities. Soft washing kills it with biodegradable detergent at garden-hose pressure, which is the only method a painted weatherboard villa should ever meet. Metro's published Wellington guide puts the typical job at $300 to $500.
Is this your stream?
Weatherboard villas, plaster bungalows, painted brick, Coloursteel: anything with a coating that high pressure would damage. Green mould on the south wall, salt film near the coast, or a general grey dullness before sale or repainting.
Driveways, paths, decks and patios belong in water blasting, where pressure is the right tool. Moss and lichen on the roof is roof treatment, a different chemistry and timeline.
What a soft wash costs in Wellington
Metro Water Blasting publishes a Wellington-specific cost guide. It is the benchmark other quotes can be checked against.
$300–$500
The typical Wellington house wash per Metro's 2026 guide. Small homes (up to about 120 square metres) run $250 to $350; medium three-to-four bedroom homes $300 to $450; large or multi-storey $400 to $650+.
$600–$1,000+
Bundles combining house wash, gutter cleaning, roof treatment and driveway cleaning run $600 to $1,000+ in the same guide. If the whole exterior is due, one visit beats three callouts.
$150–$250
Metro's guide calls out $150 to $250 water-only jobs: no treatment, mould back in months, paint at risk. The gap between cheap and professional is the chemistry, and the chemistry is the point.
Wellington soft wash providers, compared
Soft-wash-first veterans, treatment-led locals and the published-price benchmark. Hover a row for the detail that matters.
Choose by situation
Clear Water Blasting has soft-washed Wellington since 2001 and states plainly that almost every house job gets chemistry and low pressure, never blasting. On a 1920s weatherboard, that experience is the product.
Metro Water Blasting's Wellington guide prices small, medium and large homes, packages, and even the cheap-job trap. Walk into every other quote conversation already knowing the territory.
Manta Wash finishes its soft wash with a chemical neutraliser rinse specifically to protect plants and pets. If the roses lean on the weatherboards, ask every quoter for the equivalent step.
PowerPro applies a post-treatment after washing to slow regrowth, and states a 5-out-of-5 Google rating on its site. Worth asking any operator what post-treatment is included, because regrowth speed is the real cost per year.
Common mistakes
Letting someone water blast your weatherboards: high pressure strips paint, forces water behind cladding, and shreds the surface of older timber. Clear Water Blasting puts the contrast at 200 to 500 PSI for soft wash versus 2,500-plus for blasting. On a painted Wellington villa, soft wash is the only correct answer.
Choosing the $150 splash-and-dash: Metro's Wellington guide calls out cheap $150 to $250 water-only jobs that skip the treatment, so the mould regrows within months and the paint may be damaged. The chemistry is the product; the water is just delivery.
Washing too rarely for the coast: Metro's guide recommends every 6 to 12 months in Wellington conditions, and every 6 to 9 months for homes near the coast or exposed to wind-driven salt. Island Bay to Seatoun, that means you.
Ignoring the stormwater drain: wash water carrying detergent and paint flakes should not run into the street drains that feed the harbour. Ask how the operator manages runoff, especially on sloped driveways that drain straight to the road.
Not protecting the garden: the detergents that kill mould can burn plants. Operators like Manta Wash apply a neutraliser rinse to protect plantings. If your garden hugs the house, ask what protection is included before the quote is accepted.
Washing the week before a southerly front: soft wash needs dwell time and a rinse, and wind-driven rain mid-job makes a mess. Wellington weather windows are real; a good operator will reschedule rather than wash into a gale.
FAQ
How much does soft washing a house cost in Wellington?
Metro Water Blasting publishes a Wellington cost guide: $300 to $500 is the typical range, with small homes (one to two bedrooms, up to about 120 square metres) at $250 to $350, medium three-to-four bedroom homes at $300 to $450, and large or multi-storey homes at $400 to $650+. Full exterior packages bundling gutters, roof treatment and driveway run $600 to $1,000+. Everyone else quotes on inspection, usually landing in the same territory.
Soft wash versus water blasting: what is the difference?
Soft washing applies a biodegradable detergent at low pressure (200 to 500 PSI) and lets chemistry kill the mould, algae and lichen before a gentle rinse. Water blasting uses 2,500-plus PSI and brute force. On painted weatherboard, plaster, brick, tile and Coloursteel, soft wash cleans deeper and does not damage the surface. Blasting belongs on concrete, not cladding.
How often should a Wellington house be washed?
Metro's Wellington guide recommends every 6 to 12 months, and every 6 to 9 months near the coast or in wind-exposed spots, because salt and wind accelerate buildup. North-facing walls stay cleaner; south-facing walls and anything shaded by the neighbour's macrocarpa go green first.
Is soft washing safe for plants and pets?
The detergents are biodegradable, but they are still biocides. Good operators pre-wet plantings, control runoff, and apply a neutraliser rinse: Manta Wash lists that step explicitly. Keep pets inside during the wash and off the lawn until it is rinsed and dry.
What should I ask before booking?
Ask whether the quote is soft wash or pressure wash, what treatment is included, whether windows and frames are part of the wash, how plants and stormwater runoff are protected, and whether a post-treatment is applied to slow regrowth. State your cladding type and any known paint issues: lead paint on older villas needs a different conversation.
Budget $300 to $500 for a typical Wellington soft wash, per Metro's published guide, and be suspicious of anything much cheaper: the chemistry is what you are paying for. Clear Water Blasting for two decades of soft-wash-first villa work, Manta Wash for plant-safe neutralising, PowerPro for regrowth post-treatment, GoClean to bundle the windows. Ask every quoter: soft wash or pressure, what treatment, what runoff protection. Three questions, and the cowboys filter themselves out.