How Does a Pressure Washer Work?

By Power Tools

March 4, 2021

Tired of your yard floor looking dull and stained? Is your lawn furniture looking dirty? Is your car in need of a deep clean?

Sometimes, scrubbing away at a tough stain with warm, soapy water isn’t enough. Neither is the harsh chemicals that promised they would work.

Luckily for you, pressure washers are the solution to every dirty outdoors problem. These powerful hoses use electricity or petrol to pressurize jets of water 100 to 200 times stronger than the pressure of regular air. The best part? They only use water and detergent – no harsh chemicals!

But, how exactly does a pressure washer work? Keep reading to find out!

What can a pressure washer clean?

In a professional setting, pressure washers are used to clean cars and factory machinery. For personal use, pressure washers are ideal for cleaning the following:

  • Driveways
  • Yard patios
  • Lawn furniture
  • Grills
  • Garbage cans
  • Fences
  • Decks
  • Siding

They are a great appliance for household cleaning due to the convenience, lack of harsh chemicals, and fast cleaning. They can rejuvenate any dirty, dull, or stained area into its original clean form within mere minutes.

Pressure washers can also be used for artistic purposes. Reverse graffiti is when people use pressure washers on a large dirty surface to create drawings. 

If you have used a pressure washer, you’ll know how satisfying it is to wash away the grime – so it’s understandable why people would want to create harmless pieces of art!

Pressure washer parts

In the simplest form, a pressure washer is just a powerful hose motored by an electric motor or gas engine. Like a regular hose, a pressure washer takes the water from the house’s water supply and shoots it out at high pressure.

Also like a regular hose, there are different accessories such as nozzles and spray guns to clean various things – as not everything can handle the extremely pressurized water.

To understand how a pressure washer works, let’s look into the various parts.

Electric motor/Gas engine

The speed of the water is determined by the type of engine or motor the pressure washer uses. Generally speaking, smaller pressure washers use electric motors and larger pressure washers use gas engines.

This is because smaller pressure washers don’t require as much energy, so they can use the electric supply more efficiently.

If you’re looking to buy a pressure washer for domestic household use, a pressure washer run by an electric motor will work just fine. Gas engine pressure washers are convenient for places with no access to electricity, which is why they are often preferred by professionals.

The motor or engine is covered by strong steel paneling that is resistant to wear and tear and the power of the water.

Water inlet

Where the pump is the outlet, the hose that connects the water supply directly to the pressure washer is the water inlet.

It takes in the water and comes with a filter to prevent debris and grit from coming out of the water. This is to stop grit from scratching your car whilst using the pressure washer!

Water pump and pump head

The water pump is essentially what mixes the detergent and the water from the faucet. Most water pumps heat this mixture up, which helps to loosen dirt and grime. These pumps can handle 1 to 2 gallons of water per minute.

The pump head is where the water comes out! This is where the user can control the speed of the motor and the pressure of the water. Various types of nozzles can be adjusted, ranging from the speed of water to the distance the water squirts.


The hose is what connects the water inlet to the pump head (the water outlet). These hoses are designed to handle high pressures, as a regular hose would break.

They are generally made of several layers of high-density plastic.

How does a pressure washer work?

Here is a step-by-step of how a pressure washer works:

  1. One hose connects to a cleaning agent (detergent) and flows the liquid into the water pump.
  2. At the same time, water from the faucet/water supply is taken in by another hose.
  3. The water pump is then powered by the motor/engine to mix the water and detergent.
  4. Once the water has been warmed in the water pump, it is pushed through a high-pressure hose and pump head. The user can use whatever pump head they like and can adjust the settings depending on the object they are cleaning.

Pros and cons of pressure washers

If you’re someone who struggles to maintain a clean yard and car, a pressure washer can be a convenient cleaning solution for you!

Pressure washers don’t have to be used regularly, so whilst they do use 1-2 gallons of water per minute, they are only used to clean something when necessary. This may work out to be more cost-effective in the long run if you were to hire a professional to wash your car or house instead.

Pressure washers are durable and designed to resist the impact of high-pressured water. They can be taken anywhere around a yard and don’t take up much space when stored away.

However, the noise levels are high due to the high-pressure. They also have a habit of spraying the dirt and grime around them (and on to the user) during cleaning, so be prepared to get a bit messy!

Final words

So, that’s how a pressure washer works! As you can see, this handy cleaning equipment isn’t complicated to understand or use. It works similarly to how a regular garden hose works, just with a motor or engine that generates high-pressured water.

Whether you have access to electricity or not, there is a pressure washer for any situation depending on the type of engine or motor. They can be used for a variety of domestic cleaning, from cars and sliding to decks and patios.

Much more convenient than scrubbing away the grime and hoping for rain to wash it away!