How Does A Pressure washer work? Step By Step Guide

The pressure washer has become one of the needy tools for the home. This is the machine that converts low pressure into high pressure, It cleans very fastly and makes the cleaning job fun. This tool replaced the previous scrubbing brush job and,

Do you want to Know that How does a Pressure washer work? it was curious to know for me when I was Using the Pressure washer long back time. the most powerful pressure washer delivers powerful performance.

Let’s understand the working principles of pressure washers step by step by covering all their working Parts.

The pressure washer may be Electric or Gas operated. Generally, the gas-operated Engine has higher Pressure than Electric.  

How does a pressure washer work

Useful Terms and Acronyms

To know How does A pressure washer works you should know these Important terms

PSI (Pounds per square inch): it is the Acronyms of pressure measurement and you should know before buying a pressure washer what is the final pressure of Machine.

The 1500 – 2000 PSI working Pressure is Enough for Household cleaning jobs like cleaning cars, muddy bikes, Decks, Patios, Driveways, outdoor surfaces. 

check out what is the good psi for pressure washer

GPM (Gallon Per Minute): it is the acronyms of Water output and flow rate measurement. The GPM shows how fast your water goes out in a minute. Higher the GPM, more the water out.

It should not be too much. For the best electric Pressure washer, 1.2 to 1.8 GPM is Enough. Otherwise, you can lose too much water.

CU (Cleaning Units): Higher cleaning units show how powerful your pressure washer is. It can be measured By multiplying PSI X GPM.

For example, 1500 PSI X 1.4 GPM, Than Cleaning units (CU) is 2100

AMPs: it measures the power of an electric motor, Higher the AMP, the More Powerful your Electric motor is. 

learn how to start a pressure washing business

Working Principle of pressure washer ?

The working principle of a pressure washer mainly depends upon the motor, Pump, Hose, and Spray wand. Let’s understand the working of a pressure washer step by step:


The motor is the First most important part, and the whole pressure washer working depends on the Motor. In electric pressure washer motor run by electricity and In gas pressure washer it is run by gasoline.

The Electric pressure washer works on an electric motor and the gas pressure washer works on Internal-combustion Engine. The engine is more powerful than motor.

It can say that it is the Heart of the Pressure washer. The motor is run by electricity or through gas. Motor Drives the Pump, the water input from the Garden hose, and Pump deliver a high water Flow rate. The pump is operated by a motor. 

The more Powerful the Motor is, the Greater the Pressure will be. Generally, The Power of the motor is measured in AMPs (Ampere) or Watt. for an Electric pressure washer, 12 to 13 AMP is considered the best motor.


OEM technology axial cam pressure washer pump diagram

the above image is the OEM technology axial cam pressure washer pump diagram, most of the electric and gas pressure washers have the axial cam pump because it is considered best for pressure washers.

To understand How does a pressure washer pump work, understand the working of the pump is quite important because the pump is another most important part of the machine. These water Pumps work on Positive Displacement.

There are 3 pistons in the water pump driven by the motor or engine these pistons continuously suck the water first and the upstroke forces the water in the outward direction.

The stroke forces water out with high-pressure Result we get the High pressure when engaged the Gun Trigger.

In an Average electric Pressure washer model, it forces the water up to 1400 to 1500 PSI (Pounds per square inch) at a flow rate of 1.2 GPM. while in gas pressure washer 2800 to 5000 PSI is average at a flow rate of 2.5 4 GPM.

The higher the GPM, the more the Flow rate or water output will be. if you understand how does a pump work then working of a pressure washer is quite simple for you.


After the working of Piston Pump, the water flows to High Pressure. This should be made with good material and tested.  it has the capacity to bear high pressure otherwise it can burst or Harm.

It can also be flexible for coil up systematically after use. 


water flows from the hose to the wand and out from the spray Nozzle with high pressure. This pressure depends upon how powerful your motor is. 

Nozzle Tip Provide you specific flow range pressure, Different cleaning jobs required different Nozzle tips. Every Pressure washer brands provide 3 to 4 Nozzle Tips.

How to use a pressure washer in 10 easy steps

After knowing How does pressure washer works, the Pressure washer Using a guide plays an important for the Efficient Cleaning and long run of your pressure washer. 

Step #1: Provide enough water supply to the water inlet of Pressure washer through the garden hose. Turn on the faucet fully. The water supply must not be more than 0.7 MPa or 102 PSI. 

Step #2: The inlet water temperature must not be more than 104℉ /40℃. Hot water can damage the Pump.

Step #3: Don’t connect the Plug with the Power supply until the assembly completes to avoid accident or injury.

Step #4: Clear all kink of cord, garden hose, and Pressure washer Hose.

Step #5: Check and tighten all the connections, and check leakage if any

Step #6: Clean the Nozzle with Nozzle clean out tool, remove all the Dirt from the nozzle and rinse

Step #7: Check the detergent tank if it is empty then fill it with more than half level if you want to use it.

Step #8: Hold the gun Tightly with Both hands

Step #9: Keep the Nozzle close to the target cleaning job and, Don’t target one point, High pressure can damage. 

Step #10: Finally Don’t spray or clean the pressure washer from gun.

How long can you run a pressure washer?

When you buy a new pressure washer read the operation manual carefully and follow all the rules mentioned in it. This question remains in every Buyer’s mind that how long can you run a pressure washer.

is 2000 PSI good for pressure washer

of course. you can run your pressure washer for a long time but you have to Give a Break in every 10 to 15 minutes to cool down your pressure washer this trick can increase the lifespan of your pressure washer and it can save from overheating of your machine. 

  • If you don’t give a break to your pressure washer then you will have to spend your valuable money in the maintenance of your machine very soon
  • Provide Enough water to the pressure washer continuously if you fail to provide water properly then it may heat up early and it can decrease the lifespan of your pressure washer.
  • Improperly installation of Nozzle can be a cause of overheating. It can be harmful to your machine.
  • The pressure washer is engineered for cold water and lukewarm water, Avoid high-temperature water for a long run.
  • Tighten all the connections properly, especially hose connection with gun and nozzle tip and garden hose connection. it can lower the pressure or harm your machine.

The Quality of your pressure washer depends on which brand pressure washer are you using and how powerful your pressure washer is. In most of the company’s operation manuals, it is mentioned that How long can you run a pressure washer and some companies don’t mention it you have to follow the rules we discussed above for better life of your pressure washer.

How does a pressure washer unloader valve work?

After the Pump working, how does a pressure washer unloader valve work is the most important part in the working of a pressure washer let’s understand this

The unloader valve is engineered to increase the water pressure and divert the water flow. It can also be used to adjust the pressure of the machine. 

Under the Pressure washer, water is pumped faster than the resulting flow rate and we use that high-pressure water to clean outdoor surfaces or any other cleaning jobs.

When you release the trigger of your Gun, Pressure Builds, and the unloader valve ball divert the flow through the bypass 

As you engage the gun Trigger again, the spring tension returns, the unloader valve ball returns, and water flow out through the gun. 

How water cleans stubborn Stains?

The water molecules have a strong Electrical polarity. Or in other words, the water molecules are strongly Positively charged from one side and strongly negatively charged from the other side. This is the important theory of How does a Pressure washer work? This property of water helps them to stick and make a bond from others by themselves. This theory works in cleaning the dirt particles, sticking with water easily, and moving away with them.

Similarly, The detergent or soap is a cleaning agent, when it mixes with water makes a bond with them then the cleaning capacity highly increases with this bond and any type of stubborn stains Clean in the tweak. 

Some stubborn stains make a strong bond, then a pressure washer helps to clean these stains easily. Pressure washer forces the water with the high pressure from 1400 to 1500 PSI with or without detergent. With this High pressure, it breaks the Bond of any type of oil, grease stains or toughest mud cakes, and does the job Easily.

The water, detergent, and High pressure can make the cleaning easy and saves your time and water. The pressure washer is the most Promising tool and became the needful Equipment for Home. 

Select Right Spray Nozzle for Right Job with Color Code

Selecting the right spray nozzle for a specific job actually saves your time and water. The color code defines Spray Nozzle and varies from each other. 

How does a pressure washer work and in other words working of pressure washer much depends upon, what nozzle are you using? The Final pressure is much dependent on Spray Nozzle. 

0° Spray Nozzle: The color code of this Nozzle is Red. It is also known as the intense jet nozzle, used mainly to cut the heavy deposit of Mud cakes, Dirt on hard surfaces.

This spray nozzle delivers high pressure and is best suited to clean Stubborn stains like grease spots and tar spots. Don’t use it on wood or siding. 

Of course, the pressure is high but the use of this nozzle is rare because it covers a small tip area. And it is unsafe for use, Wear Personal protective equipment when using this and keep away from Kids.

15° Spray Nozzle: The color code of this Nozzle is Yellow. It is used for high-pressure cleaning jobs on hard surfaces like outdoor surfaces, concrete, grease or oil stains, paints, grime Etc. This high-pressure Spray nozzle can harm the softer surfaces. 

25° Spray Nozzle:  The color code of this Nozzle is green. This spray nozzle makes a 25° spray angle, this is one of the most usable or common spray nozzles for home use. It is used to clean mainly for cars, Decks, Boats, Patio Furniture, Driveways Etc. 

40° Spray Nozzle: The color code of this Nozzle is green White. It creates wider spray and covers 40° spray. Mainly used to clean for fragile surfaces like windows, flower pots, blinds, etc.

60° Spray Nozzle: The color code of this Nozzle is green Black. It is also known as soap Nozzle or low-pressure Nozzle. Whenever the detergent is required to clean using this nozzle. It is used to clean stains or grimy surfaces.

Turbo /Rotary Nozzle: some pressure washer brands provide this nozzle. It is one of the best spray nozzles. It delivers the force of 0° Nozzle and covers the spray area of 25° nozzle plus also rotates at 1800-3000 RPM.

The spray makes a rotating cone shape on heating the surface that’s why it is known as a rotating Nozzle.

check this out How does a Karcher pressure work by Karcher

Safety Precautions when Using Pressure washer

  • Don’t Point direct the spray gun at Person, pets and electric equipment
  • Keep away the children and the pressure washer not be used by children
  • Use personal protective equipment most importantly Safety glasses and Safety Boots
  • Don’t clean the flammable liquids and chemical

FAQ about Pressure washer working principle?

Q.1) Does a pressure washer need water pressure?

pressure washer requires a continuous flow of water so it can convert into a high pressure, if it does not get continuous flow it will not work properly.

Q.2) Is it worth it to buy a pressure washer?

Yes, obviously pressure washer is a much-needed tool for any type of home cleaning job to keep hygiene around the house for better health of the family.

Q.3) Do you need special soap for the pressure washer?

Yes, the pressure washer requires different soaps and detergents because some high chemical formulas of soaps can damage or choke the pressure washer pumps.


To convert low pressure into high pressure we use the tool called a pressure washer. The working of this tool is quite simple. We covered the How does a pressure washer work and understand the working Principle Here. The motor and Pump work together for High-pressure output. This tool makes the cleaning job easy. 

We have to use the pressure washer with the following precautions and safety guides for the Efficient use of the tool.