The Best Time to Pressure Wash Your House in Vancouver

Metro Vancouver takes on roughly 1,100 mm of rain in a normal year, and the bulk of it lands between October and April. For an exterior surface, that means eight months of near-continuous moisture at mild temperatures, which is precisely the recipe moss, green algae, and lichen are waiting for. Moss anchors into siding and concrete with root-like rhizoids that hold a film of water against the surface long after the rain stops, quietly accelerating decay underneath.

Green algae is the other regular. It feeds on the organic film our tree canopy supplies, cedar debris, alder and birch pollen, and general urban grime, and it shows up first as a faint green shadow on the shady side of the house. Left through a winter, that shadow becomes a slick coating on walkways and a stain on siding that a garden hose will not touch.

That is why the generic advice you will read in national guides, wash anytime it is warm, undersells the problem here. In this climate the question is not just when washing is comfortable; it is when washing will actually hold. Wash in late fall and the regrowth season starts the same week. Wash at the front of the dry season and you bank five or six clean months before the rain returns.

April is the earliest sensible start, and only for hard surfaces. Driveways, walkways, and patios can be washed between showers because nobody needs them bone dry afterward. It is also when winter's black algae film is most obvious, so you can see exactly what you are removing.

Siding season lands in May and June. Temperatures sit comfortably in the 5 to 24 C band that cleaning solutions like, the cedar and alder pollen dump is mostly finished, and there is enough forecast reliability to find a 48-hour dry stretch. Washing in this window removes winter grime and pollen film in one pass, which is exactly what the annual siding wash is for.

July through September is the money window for anything that has a second step. Exterior painting, deck sealing, fence staining, and pre-sale spruce-ups all need the surface genuinely dry, and these are the only months Vancouver hands out 72-hour dry guarantees with any regularity. It is also when strata corporations run building-wide washing of parkades, walkways, and garbage areas, because notice periods and dry forecasts finally line up.

October is the closing bell. An early-October wash of flatwork ahead of the rain season is a defensive move that keeps walkways safe through winter, but siding washed this late will not stay clean for long. From November to March, washing is triage only: a slippery walkway or an emergency before a listing, done between systems, with expectations set accordingly.

For a plain water rinse of concrete, light rain is mostly harmless; the surface is getting wet either way. Where rain wrecks the job is everywhere else. Detergents and moss treatments dilute before they finish working, so the organic growth you thought you killed comes back within weeks. Siding washed in the rain never dries, which defeats the point of removing the moisture-holding growth in the first place.

There is also a safety line that gets crossed quickly. Wet algae on a sloped driveway is one of the most slippery surfaces a homeowner will ever stand on, and adding a pressure washer's recoil to that footing is how people get hurt. Professional crews will rinse flatwork in drizzle, but they will not run detergent passes, ladder-adjacent work, or wood in active rain.

The working rule we use on scheduling: if the job involves cleaning solutions, wood, or any follow-up coat of paint, stain, or sealer, it waits for a dry window. If it is bare concrete and a rinse, the forecast can be imperfect.

Frequency is where Vancouver diverges hardest from the standard advice. A once-a-year siding wash is still right, but flatwork that a drier city could leave for eighteen months will be green and slick here within eight. Homes under mature trees, common across North Vancouver, West Vancouver, and Burke Mountain, sit at the aggressive end of every range because canopy shade and debris feed regrowth all year.

In practice that means siding once a year in late spring, driveways and walkways every six months, decks annually before sealing, and fences every year or two. The table below lays out the full cadence, window by window.

Paint does not bond to chalk, mildew, or algae, so every exterior painting project here starts with a wash. The part that surprises homeowners is the wait afterward. You need 24 to 72 hours of genuinely dry weather before the first coat, at least 48 for wood, and painters will want surface moisture under about 15 percent before they commit. That means the wash and the paint job need to live inside the same dry week, which in practice means booking both for July, August, or early September.

Deck sealing and fence staining follow the same logic with even less forgiveness, because horizontal wood drinks water and gives it back slowly. Wash the deck, give it two full dry days, then seal, and do all three before the September long weekend rather than gambling on October.

Pre-sale washes are their own category. If a listing is going live, washing the driveway, entry, and siding a week before photos is one of the highest-return jobs in the exterior category, and pairing it with a window cleaning pass makes the whole frontage read as maintained. Realtors book these year-round, which is fine, as long as everyone understands a November wash is for the photos, not for longevity.

A rented or consumer machine handles flat concrete well, and a careful homeowner can keep a driveway respectable on the six-month cycle. The jobs worth handing off share a theme: risk that is not obvious until it goes wrong. High pressure aimed up under vinyl laps drives water into the wall assembly. Older stucco and cedar want a soft wash, low pressure plus the right solution, or they scar; and two-storey walls put untrained hands on ladders with recoil, the single most common way these projects end badly.

There are also two local wrinkles worth knowing. During summer water restrictions, regional rules limit some residential washing, while professional outfits run efficient equipment that stays onside. And for strata buildings, councils typically require proof of insurance before anyone washes shared surfaces, which takes DIY off the table for common areas entirely.

If you want the timing handled for you, our pressure washing service runs across Metro Vancouver through the dry season, and we schedule shaded, moss-prone properties into the earliest windows on purpose. Either way, put the wash on the calendar in spring; the good weeks go fast.