How To Use A Pressure Washer

If you’re reading this, you’re probably the proud owner of a brand new pressure washer, and you’re looking for some tips and hints on how to use it. The first thing you need to know is, you just opened a whole new world of cleaning fun. There’s nothing quite so satisfying as watching dirt disappear under a stream of high-powered water pressure.

Before you start getting busy with the pressure washer, here are a few words of caution that might save you a trip to the hospital. Whether you own a petrol-powered or an electric-powered pressure washer, you can still cause some serious damage to property and serious injury to yourself. Let’s have a quick look at the how and why of danger with a pressure washer.

Is Using A Pressure Washer Dangerous?

The first thing you need to know is about water pressure. Water pressure is measured in Pounds per Square inch (PSi) and pressure washers fall into 2 groups, with very different PSi values. Electric-powered pressure washers tend to be less powerful with an average PSi range of around 1000 to 2000. Gas or petrol-powered models have more power averaging at between 2000 PSi to 3000 PSi.

To put that into perspective, below is a shortlist of the PSi needed to cut through various materials. You’ll notice that these are all in the parameters of the PSi exerted by pressure washers.

Material	PSi needed to cut through the material
Softwood (pine)	2,321 PSi
Glass	1,914 PSi
Concrete	1,740 PSi
Human skin	1,160 PSi
Rubber	928 PSi

Now you get an idea of just how powerful a pressure washer can be, you can understand why safety precautions are necessary. So let’s look at how to use a pressure washer safely.

Safety Advice For Using A Pressure Washer

The following advice is applicable to both types of pressure washers.

• Read the users manual
  You will have received a users manual with your pressure washer, read it from cover to cover and familiarise yourself with all the parts and functions of your new machine. This even applies if you’ve owned a pressure washer before because models vary on how they operate.
• Wear personal protective equipment (PPE)
  Always wear boots, gloves, goggles, face mask, and protect your arms and legs (no shorts or short-sleeved shirts).
• Clear any obstacles
  Remove all tripping hazards such as toys, pot plants, garden furniture, children, pets, wires and hoses. Cover any electrical items like lights and vents and be sure all windows are closed.
• Put the ladder out of sight
  Due to the amount of force exerted from a pressure washer you definitely don’t want to be up a ladder. Have you seen the film Ghostbusters? Do you really want that to be you, flying backwards from the top of a ladder propelled by the sheer force of the water from the pressure hose? If you need to pressure wash something high up, use a telescopic wand or lance.
• Be in full control
  If you happen to spray directly at yourself, another person or a pet, you’re liable to cause a serious injury. Never under any circumstances spray a pressure washer at anyone.
• Always start with the lowest pressure
  We’ve not got onto the nozzles yet but always start off with the lowest pressure you can and build-up gradually. You might not need as much power as you think to remove that dirt.

Here are a couple of safety tips that are type-specific.

 For Electric-Powered Pressure Washers 

never use an extension cable longer than 10 metres (30 ft) in length and be sure it has a constant rating of 13 amps. Check your handbook first, as some manufacturers say not to use an extension cable and if you do, you could void your warranty.

For Gas/Petrol Powered Pressure Washers

Never use in a confined space-that means always use outdoors and in an airy place (not shut up around bushes, or between the garage wall and the fence). Adequate ventilation is of paramount importance because petrol engines release carbon monoxide through the exhaust. This is a killer and if you experience any of the following symptoms call a doctor immediately.

• Headache
• Fatigue
• Dizziness
• Trouble breathing
• Sickness

Turn the engine off and get into fresh air while you wait for medical assistance.

The Correct way To Start A Pressure Washer

To be sure of a trouble-free session with your pressure washer always follow this step by step guide to start your machine.

1. Grab a broom
   Sweep up all loose dirt, dust and other debris from the area you’re planning on cleaning.
2. Connect the garden hose
   Connect the garden hose to the water supply and connect the other end to the inlet on your pressure washer.
3. Check all hoses
   Check that neither the garden hose nor the power hose has any kinks or blockages.
4. Add detergent
   If you’re using detergent, fill the reservoir with the correct detergent(making sure it’s mixed right).
5. Turn the water supply on
   Turn the outdoor tap on fully. 
6. Allow water to flow
   Without touching anything else allow the water to flow through the pressure washer for a minute or two.
7. Connect the power hose
   Connect the power hose to the outlet connector on the pressure washer.
8. Clear the system of any air
   Press the trigger on the wand to force water through to the high-pressure hose and into the wand. Forcing any air out at the same time.
9. Look for leaks
   Check both hoses and the pressure washer itself along with the connectors for any water leaks.
10. Start the machine
    For electric models plug into the socket, turn the power on and turn the machine to on. For petrol models place one foot against a wheel to steady it, pull the starter cord, once it catches adjust the choke and throttle as necessary.
11. Press the trigger
    Press the trigger again, your pressure washer should be operational now.

How Often Should You Pressure Wash Your House?

This question gets asked again and again, the smart answer is when it gets dirty. But the really helpful answer is to look at the averages and work it out from there. So we’ve put together this easy to follow chart for your convenience.

Area to be cleaned	Frequency of cleaning
Concrete driveway	Once a year
Wooden decking	Once a year
Vinyl sidings and/or fascias	Every 2 years
Stone or brick patios/paths	Every 3 years

Now let’s have a closer look at those nozzles.

Pressure Washer Nozzles Chart

Nozzle colour	Nozzle used for
Red	Removing tough stains including rust, very powerful spray.
Yellow	Removing dirt mildew, mould, or paint,
Green	Cars, boats, caravans, garden furniture, decking, drives
White	Gentle spray best for windows and delicate surfaces
Black	Low-pressure nozzle used to apply soaps and detergents

Some models also include a turbo nozzle which is like a cross between the red and the green nozzle. Used mainly for caked-on dirt and stains.

What Not To Wash With A Pressure Washer

It’s easy to get carried away with a pressure washer, suddenly everything looks dirty and in need of a spray with the pressure washer. But take care, there are a few things that should never be pressure washed these include:

• Electrical equipment
  Like electricity meters and electric panels, they might be outdoors and designed to take the worst a British winter can throw at them but not the force from a pressure washer. Remember even if they do belong to the power company, if they can prove you caused the damage, you’ll be liable to pay for repairing it.
• Air conditioning unit
  No matter how dirty it looks, the air conditioning unit will not withstand too much pressure or too much water.
• Lead paint
  Some older properties still have some remnants of lead paint. This should only be removed by a professional. Lead paint is poisonous and dangerous, it takes an expert to deal with it safely.
• Wooden buildings
  Garden sheds and outbuildings made of wood can be pressure washed, but as a newbie, you’ll probably be lacking the necessary skill levels to do so without damaging the wood and causing long-lasting problems with mould etc.
• Some roof coverings
  Slates are only held in place by one copper nail. Over time this nail wears and is easily dislodged by highly-pressurised water. If you do decide to use a telescopic pole to clean the roof be extra careful depending on what your roof is made from.

Frequently Asked Questions