How Does a Pressure Washer Work?

When it comes to the best garden tools, a pressure washer is one of the most versatile.

The first thing that springs to mind is someone cleaning their car at a fraction the cost of a carwash. What else can you clean with a pressure washer aside from your vehicle?

  • Boats
  • Tiled patios
  • Concrete driveways
  • Wooden decking
  • Home exterior
  • Fencing
  • Stairs
  • Walkways
  • Grills
  • Outdoor furniture

As you can see, investing in one of these wonderful appliances is a first-rate cleaning shortcut.

We will look today at one of the most common questions of all: how does a pressure washer work?

First thing’s first, though…

We’ll look at the basics of what makes up a pressure washer then walk you through how this equipment works.


Luckily, pressure washers do not come with a string of difficult, technical language to pick up.

There are really two main terms that you need to be aware of:

  • GPM: Gallons Per minute. This is the flow of water that’s delivered to your spray gun. It’s this which allows you to break down all the dirt and wash it away
  • PSI: Pounds Per Square Inch. This measurement relates to the water pressure measured at the output. This pressure gives you sufficient power to blast through any dirt

Parts of a Pressure Washer

pressure washer

Source: HSS Hire

A pressure washer is a simple yet incredibly efficient piece of kit.

Most of these high-powered cleaners feature a metal frame together with the following primary components:

  • Gas engine or electric motor
  • Water inlet
  • Water pump
  • High-pressure hose
  • Attachments: wand and nozzle

Gas or Electric?

Source: Best Pressure Washer

Light-duty pressure washers strictly for home use generally run from the electric supply. These washers are quiet, maneuverable and very compact.

When you step up a notch to the medium and heavy-duty commercial pressure washers, you will normally find them equipped with a gas engine. These models are bulkier and generate a reasonable amount of noise. The significant advantage, aside from power, is not being restricted to a power outlet. If you are working in hard-to-reach places, there’s no substitute for a powerful gas-engined pressure washer.

Water Inlet

pressure washer

The water inlet is a simple hose that connects up your pressure washer to the supply of water.

Since you will be cleaning up filth, the dirt and debris can pretty easily kick back and end up clogging your jet washer. For this reason, most come with a handy filter to minimize the chance of this happening. Aside from causing problems with your washer, there’s always a risk that any dirt like this will be shot back out at incredible pace.

Water Pump

The water pump is absolutely central to your pressure washer.

This works in the same fashion as a hand-operated pump except it’s driven extremely rapidly by a powerful motor rather than by hand.

Water is sucked from the faucet when the engine pulls the pump in one direction. When the pump is pulled the other way, water will come shooting out of the high-powered jet.

Most pumps are designed to cope with a flow of 1-2 gallons per minute.

High-Pressure Hose

The tube running between the washer and the water supply is reinforced with high-density plastic and wire mesh. This is to ensure that it can deal with the pressure thrown its way. A regular hose would not be man enough for the job.

With hoses, you need to look out for a pressure rating that exceeds the rating of the pump on your jet washer.


Different pressure washers come with different attachments.

These can vary from a straightforward trigger gun through to a rotating brush or wand.

You can change the angle and the force depending on whether you use a pinpoint nozzle or a wider one.

How Does a Pressure Washer Work?

The way in which a pressure washer works is actually very simple.

Here’s a very basic breakdown of what takes place so that you can leave your car or patio sparkling clean…

  1. Your chosen detergent flows in through one of the hoses. This detergent comes from a bottle or container
  2. Cold water from the faucet comes in through a second hose. This water is filtered on the way out
  3. The pressure washer is powered by its electric motor or gasoline engine
  4. The water pump is also known as an impeller. When it’s powered by the motor, this pump draws in the water and detergent and mixes them up
  5. The majority of pressure washers will also heat up the water. A temperature of anywhere between 50 and 70 degrees C is ideal
  6. The hot and soapy water will be squirted out through the exit hose and attachment. A thin nozzle will help to boost the pressure even further

So, as you can see, the mechanics of a pressure washer are pretty simple.

Does a Pressure Washer Have Any Drawbacks?

Like any appliance, a pressure washer is not perfect. There are a few minor disadvantages to using one.

  • Pressure washers can be very noisy. The sound level kicked out is usually 75 decibels or above
  • They use a great deal of water. If you’re using a jet washer, you could easily get through 2 gallons of water in a minute. The key here is to make sure that you use your washer in an area where there’s adequate drainage
  • Beware of the ever-present danger of using water and electricity together. Pressure washers are well-insulated and safe to use but it always pays to be on your guard
  • The way in which pressure washers get things clean is by blasting the dirt very forcefully. Be methodical to make sure you don’t make so much mess that you will be cleaning up after you have cleaned up! The idea is to save yourself time.


We hope you have found this look at how a pressure washer works useful and informative.

If you have any comments or feedback then please get in touch. We are always delighted to hear from our readers.

Now happy cleaning!