How to Clean a Dirty Patio Without a Pressure Washer (and When to Book One)

A pressure washer is fast, and speed is the only category where it clearly wins. What it does not do is discriminate. At the pressures a typical gas machine delivers, a narrow fan tip strips the surface cream off concrete pavers and blasts jointing sand out of the gaps. It also leaves the striped wand marks you see on half the patios in Metro Vancouver every summer. Those stripes are permanent. The sand loss is worse, because once the joints are empty the pavers start to rock and weeds root straight into the gap.

Hand cleaning takes longer and removes the same organic growth. A stiff nylon brush plus a surfactant plus dwell time is the same chemistry a professional uses, just applied with your shoulder instead of a pump. For a typical 200 to 300 square foot patio you are looking at two to three hours including drying, spread over a dry afternoon.

Where it stops working: hand cleaning will not lift deep-set oil stains, rust bleed from patio furniture feet, or mature lichen. Those need either a targeted poultice or professional equipment, and no amount of scrubbing changes that.

This is the part every UK and US guide on this topic misses, and it changes the whole job here. Metro Vancouver's Drinking Water Conservation Plan treats washing impermeable surfaces as a restricted activity. The wording is specific, and it turns on three exceptions. Health or safety. Preparing the surface for painting or a similar treatment. Aesthetic cleaning carried out by a commercial cleaning operation. Everything else is prohibited.

Read that last clause again, because it is the one homeowners get wrong. If your patio is simply green and you want it to look nicer, that is aesthetic cleaning, and under the plan a commercial cleaning operation is the party permitted to do it. If the growth has made the surface genuinely slippery, that is a health or safety reason and you can address it yourself. The distinction is not about the tool you hold. It is about the purpose of the wash. That is our reading of the published plan rather than legal advice, and individual municipalities can set stricter local bylaws on top of it, so your city's water page is the last word.

As of publication in late July 2026, Stage 2 restrictions were in effect region wide, after the region stepped down from Stage 3, and Metro Vancouver publishes the active stage as conditions change. Stage 1 applies automatically every year from May 1 to October 15, so there is no summer in which none of this applies. Check the current stage before you start rather than assuming last year's rules.

There is a second rule that catches people out regardless of stage. Every hose must carry an automatic shut-off device, which the plan defines as one that stops the water unless hand pressure is applied. A hose left running into a drain while you scrub is exactly the waste the plan exists to prevent.

Metro Vancouver grows all three exceptionally well. Our wet season runs roughly October through April, and a north-facing patio under a cedar can stay damp for six months without a single properly dry day. That is ideal habitat, and it is why patios here go green faster than the same slab would in Calgary.

Moss is the easy one. It is a plant with shallow anchoring, it sits on top of the surface and in the joints, and it lifts mechanically. Scrape the thick pads off dry with a stiff brush or a jointing knife before you introduce any water at all, and you remove most of the volume in fifteen minutes. Wetting moss first just turns it into a sponge you then have to push around.

Green algae is a film, not a plant. It will not scrape, because there is nothing to grip. Algae needs a surfactant and dwell time to break the biofilm down. That is why the commonest DIY mistake is scrubbing immediately instead of waiting the ten to fifteen minutes for the solution to work. Let the chemistry do the labour and the brush becomes a formality.

Lichen is the one to be realistic about. Those flat grey, white or orange crusty discs are a fungus and alga living together, and they etch into the stone surface to anchor. Hand cleaning removes the top and leaves a ghost outline. If your patio is covered in lichen discs, a hand clean will improve it and will not erase it, and anyone who promises otherwise has not tried.

For general grime and light algae, hot water with a good squeeze of dish soap is genuinely sufficient. Most patio soil is organic and greasy, and a surfactant is the right answer to a greasy problem. For established algae and moss staining, oxygen bleach, sold as sodium percarbonate, is the better choice: dissolve it in hot water, apply it, and give it fifteen minutes. It breaks down into soda ash, water and oxygen, which is a far kinder outcome for whatever is growing beside your patio.

Now the damage list. Vinegar is the most recommended and most misapplied patio remedy on the internet. Acetic acid attacks the cement paste in concrete pavers and etches limestone and other natural stone permanently, and it dissolves the fine binder in jointing sand. Manufacturers such as Unilock publish maintenance guidance that treats acids as a specialist, last-resort intervention on pavers rather than a routine cleaner, and that caution exists for good reason.

Chlorine bleach earns its own warning. It will kill algae, and it will also strip colour from pigmented pavers unevenly, corrode any metal fixings, and burn plants at the patio edge. If you have ever seen a patio with a pale ghost patch, that is usually where somebody poured neat bleach. Never mix it with anything else, and specifically never with vinegar or ammonia, which produces toxic gas. In a garden setting there is rarely a reason to reach for it at all.

Last question in this section, and it is the one nobody asks: where does the dirty water end up? Metro Vancouver's storm drains discharge directly to the nearest creek, river or ocean with no treatment in between, and soaps and garden chemicals carried in that runoff reach fish habitat. Sweep or squeegee your dirty water onto soil, lawn or a gravel bed where it can filter, and keep it away from the street drain. In a region with salmon-bearing streams inside residential neighbourhoods, that is not a small detail.

Moss and algae are moisture problems wearing a cleaning problem's clothes. If the patio stays wet, it goes green again, and no product changes that. The single highest-value job after cleaning is cutting back whatever overhangs the patio. Lifting the canopy of a cedar or laurel to get two or three more hours of direct sun on the slabs does more over the following seasons than any treatment you can buy.

Drainage is next. Walk the patio during actual rain, not on a dry day, and find where water sits. A slab that ponds is a slab that will be green by February. Re-levelling one or two settled pavers, clearing a blocked channel drain, or extending a downspout so it discharges past the patio instead of onto it will fix a recurring green patch permanently.

Keep organic debris moving. Leaf litter left on a patio through a Metro Vancouver November composts in place, feeds the algae and stains the stone with tannin. A two minute sweep every week or two through the fall is worth more than a spring deep clean. If you have already worked through a wider home cleaning routine, the patio sweep slots naturally into the same outdoor pass as gutters and window sills.

Timing matters more here than almost anywhere. Late July through September is the dependable dry window, and it is the only stretch where a patio reliably dries fully before the next rain. Our guide on the best time to pressure wash in Vancouver breaks the calendar down surface by surface, and the same logic applies to hand cleaning.

The first is scale. Somewhere past about 400 square feet, or on a multi-level deck and stair arrangement, hand cleaning stops being a satisfying Saturday and becomes two full weekends. The second is stain type. A brush only removes what is sitting on the surface, and lichen, oil and rust have all bonded into it. More scrubbing does not move a stain into a different category.

The third is regulatory. If the honest answer is that your patio is not dangerous, just unsightly, the conservation plan puts that wash in a commercial operator's hands. Booking pressure washing there is not a shortcut, it is the compliant route. It also gets you a surface cleaner attachment, which spreads pressure across a disc instead of carving wand stripes into your slabs.

Cost is usually the deciding factor, and it is worth checking real numbers before assuming. Our breakdown of pressure washing costs in Metro Vancouver covers driveway and patio add-on pricing, and most homeowners find a patio bundled with siding or a driveway costs meaningfully less than booking it alone. Homes on the North Shore usually sit at the higher end, because North Vancouver moss loads are the heaviest in the region.

One practical note before you call anyone. The wet season that greened your slabs also filmed the windows and pushed grit through the house. Patio work prices better attached to house cleaning or window cleaning than booked as its own trip.