Use a pressure washer with water on first, a wide fan, and about 30 cm of air between the lance and the surface. A 110 to 145 bar mains machine will wash a car, a patio, bins and furniture if you treat each surface as a different job. The same jet that lifts moss from concrete will cut paint, raise timber grain and blow sand out of block paving.
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This is first-use for a UK house with a tap and a 13A socket. It is not a shortlist. For the machine itself, start with the cars guide if you have a tap, or the cordless guide if you do not.
Before you start
Hosepipe bans. A Temporary Use Ban usually treats a mains-fed washer as a hosepipe. A bucket is normally still allowed. Check your supplier first.
Runoff. Keep dirty water out of a surface-water gully, a soakaway or a stream. Aim at a foul or combined drain, or soil on your own plot. If you cannot control the flow, skip the soap.
Neighbours and weather. Do the long patio on a Saturday morning, not a Sunday evening. Not in rain, a strong wind or a hard frost. Not a car in midday sun. Glasses if it will splash. Closed shoes. Trigger lock on when you put the gun down. Never from a ladder. Never at a person or a pet.
How to set up a pressure washer
Water first, power second.
- Read the sheet in the box.
- Park on dry ground so the hose reaches and the plug stays dry.
- Rinse the inlet filter.
- Fit a half-inch garden hose, unkinked, fully off the reel.
- Turn the tap on fully and purge water through the gun before you switch on.
- Plug into a splashproof outdoor socket on a 30 mA RCD.
- If you need a lead, use an outdoor-rated one, fully unwound. Do not daisy-chain indoor reels.
- Fit a wide fan or Vario. Start on the lowest setting, not the dirt blaster.
- Switch on, then pull the trigger. If nothing comes out, stop and purge again. Do not run a dry pump.
- When you stop: lock the trigger, switch off, unplug, tap off, then squeeze the trigger to dump residual pressure.
If the motor starts then dies, or the RCD trips, stop.
Nozzles and distance
The nozzle does more work than the bar figure on the box. A 130 bar machine on a 40° fan, a metre back, is gentle. The same machine on a 0° pencil jet, 5 cm from the surface, is a cutter.
Fan or Vario for cars, furniture and a first pass on stone. Soap tip applies detergent and does not wash. Dirt blaster is for concrete and dirty block, never paint, glass, tyres, timber or pointing. Pencil / 0° is a cutter. Never on a car.
Kärcher’s own high-pressure working distance is about 30 cm. On a car they want a flat jet, at least 15 cm from the paint and 30 cm from the tyres. Further is safer on old lacquer, wraps, chrome and cameras. Keep the lance moving. A parked jet etches a stripe. Test a hidden corner first.
| Job | Tip | Starting distance | Notes |
|---|---|---|---|
| Car paint and glass | Wide fan / Vario low | 30 cm or more (15 cm minimum) | No rotary, no pencil |
| Tyres and arches | Wide fan | 30 cm or more | Foam and a brush beat more bar |
| Patio, concrete, dirty block | Fan, then rotary if needed | 30 cm, then closer on a test patch | Patio head if you have one |
| York stone, sandstone | Wide fan only | 40 to 50 cm | Easy to bruise |
| Timber or composite decking | Wide fan, low setting | 30 cm or more | With the grain, keep moving |
| Bins and plastic furniture | Fan | 30 cm | Watch stickers and wheels |
| Oil on a drive | Soap tip, then fan | 30 cm | Detergent first, not more pressure |
Surface by surface
Cars. Pre-rinse, foam, mitt if needed, rinse on the same wide fan. Seals, cameras, sensors and soft-tops are how a ten-minute wash becomes a bill. Full method on the cars page. Petrol is the wrong tool for gloss paint.
Patio and drive. Sweep first. A hooded Kärcher patio cleaner keeps the jet on the slab. Walk backwards in overlapping passes. York stone stays on the fan. A rotary jet in a block joint empties the sand. Keep the jet off air bricks, weepholes and the damp-proof course.
Decking. Timber wants a wide fan, with the grain, further back than you think. Composite: check the board maker. If the booklet is missing, wide fan, 30 cm or more, no rotary, no bleach, and do not fire into the gaps.
Bins and furniture. Wash a bin on a drain or soil you own, inside first, on a fan. Plastic chairs at 30 cm. Teak wants the decking rules. Cushions off. Bikes: fan on the frame, keep the jet out of hubs and e-bike electrics.
Soap
Soap is a low-pressure job. Apply, wait, rinse on the fan. Car shampoo on paint. Stone cleaner on slabs. Washing-up liquid strips wax. Patio detergent dulls lacquer. If the only path is a road gully, skip the detergent.
What not to blast
- People, pets, bare skin. The jet injects water and dirt.
- Live electrics. Outdoor sockets, lights, an EV charger, a heat pump, a spur on the wall.
- Windows at close range. A rotary jet will craze a unit or drive water into the frame.
- Soft render, pebble dash, crumbling mortar.
- Air bricks, weepholes, the DPC.
- Asbestos cement. Old garage roofs, some soffits, some sheds. If you think it might be asbestos, stop.
- Rotten fences and flaking paint.
- Engine bays, fuse boxes, aftermarket ECUs.
- Soft-top fabric and plastic rear windows.
- A ladder, a roof, or anything that needs both hands for balance.
Frost, drain-down and storage
A UK frost will crack a pump that still has water in it. A lot of domestic warranties exclude that. Empty the machine every time the forecast drops to zero, not only at the end of October.
- Turn the machine off and unplug it.
- Shut the tap. Disconnect the garden hose.
- Squeeze the trigger to dump pressure.
- Disconnect the high-pressure hose and hang it so it empties.
- With the inlet open and the high-pressure hose off, switch the machine on for a few seconds only, until the pump stops spitting water, then switch off. That is the brief dry run the manuals describe, not a minute of a screaming motor.
- Empty any detergent bottle. Tip water out of the patio head and the gun.
- Store the body, gun, hose and lances in a frost-free room. An unheated shed is not frost-free in January, even with a cover on the machine.
Rinse the inlet filter. Coil the hose loose. If the machine must sit in a cold garage, a pump-guard kit is the extra step. It is not a reason to skip the drain-down.
When cordless or petrol is the better tool
A mains washer is the default if you have a tap and a socket. No tap or socket: a battery gun or a tank trolley on the cordless guide. A long yard the lead will not reach: the petrol guide. One small car, once: a bucket still wins.
Mains electric
Best pressure washer for cars
£169
The 110 to 145 bar tap-fed machines that also do a patio. Start here if you have a socket and a hose.
No tap or socket
Best cordless pressure washer UK
From about £120
Battery guns and tank trolleys for a front garden, a car park or a campervan pitch.
FAQ
How far should I hold the lance?
Start at about 30 cm on a wide fan and only move in after a test patch. On a car, Kärcher wants at least 15 cm from paint and 30 cm from tyres. On timber, composite and soft stone, stay at 30 cm or more and keep the lance moving.
Can I use an extension lead?
Only an outdoor-rated lead, fully unwound, on an RCD-protected supply, with the coupling kept dry. Do not daisy-chain indoor reels.
What happens if I leave water in the machine over a frost?
The pump can crack. Drain the hoses, dump the residual water with a brief run, and store the body indoors. Frost damage is often outside the warranty.