Why Pressure Washer Loses Pressure?

Pressure washers are being used all over the world for cleaning. It is the most outstanding complaint of the customers that pressure washers, after some time, lose pressure. If a pressure washer loses pressure, it is no better than the simple garden hose used by many people for cleaning purposes. In this article, you will get know about what pressure washers are and how do they work. After that, a very important discussion that when and why pressure washer loses pressure.

We will provide you with reasons for the matter, and finally, you will realize that how your problem can be fixed or even best how it can be prevented from happening in the first place. So, sit tight and have a read.

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What Are Pressure Washers?

Most of you people think those clean surroundings is a way to living a healthy life. We second that opinion. For making your environment clean and free from all kinds of dirt, pressure washers are used. It is a machine, which supplies high-pressure water from outlet hose to make the dirt unstick from your living space.

It goes a long way in keeping your environment clean. Mostly its power is expressed from two variables. The GPM and PSI of the machine, i.e., Gallons per Minute and Pounds per Square Inch, respectively. The GPM is the water flow provided by your machine to the spraying nozzles whereas the PSI is output power of the water provided to you by the machine. You can choose the item according to your need because they come in different GPMs and PSIs.

How Does a Pressure Washer Work?

Pressure washers are known to blast the dirt away with 75% more pressure than a simple garden hose. They do have a low-pressure option, as well, to clean delicate surfaces and materials. 

There are two main types of a pressure washer: one is Electric, and the other one is Gas.

The electric models run on electricity and are known to be small and compact. They are best for most of the domestic usage. They do not have enormous pressure thus are perfect for residential usage.

The gas-powered models are stronger than the electric ones. They have an advantage of increased power with the addition of more easy movement as they do not have electric cables attached and you can move them conveniently to the spots where there is no going for the electric models. These models are mostly used for professional purposes.

The efficiency of your pressure washer can be analyzed by checking its PSI and GPM. PSI is Pounds per Sq. Inch and through that, you come to know how much pressure does your washer offers for penetration of the dirt. Secondly, the GPM is gallons per minute, and it is the quantity of water that is offered by your pressure washer. The more the PSI and GPM, more are the chances of dirt being washed off easily.

Through inlet stream, water goes into the machine and comes with pressure according to your requirement, through outlet hose. It is as simple as that.

Why Pressure Washer Loses Pressure?

Sometimes pressure washers stop performing according to their capabilities. There are many reasons for that. Some of those reasons are stipulated below; give them a read for better understanding of your machine.

1) Incompatible Hose

Sometimes your pressure washer is unable to provide high-pressure because of the incompatibility issues of hose you are using. The hose installed for pressure is wider than required. The diameters of the hoses look similar, but the difference in the fraction of an inch can cause your pressure washer to work abnormally.

2) Pressure Regulator

Some of the pressure washer machines are equipped with the pressure regulator, which help you in regulating pressure according to your requirement. Water is pumped through the input hose and directed towards the outlet hose. The pressure regulator system does not stop the backflow of water into the pump thus increases problems with the course of time.

3) Unloader Valve

Some of the pressure washer models are equipped with the unloader valve. This valve bypasses the water flow when the outlet trigger is not using the water. It also helps in increasing or decreasing the pressure upon your discretion. The improper adjustment of unloader valve also causes your machine to lose pressure.

4) Nozzles

Most commonly, the reason behind the losing of pressure is unclean nozzles. You know that the nozzles directly use the water from the pump and if the nozzle is filled with precipitates of dirt, you can lose pressure of your machine. Sometimes the nozzles are worn out due to usage, which also results in losing of pressure.

5) Dirt in the Pump

Another common reason for low pressure of your pressure washer is the presence of dirt in the pump. Filters are installed in the pumps to save the pump from the dirt. If dirt accesses the pump even in the presence of the filter, then there is a strong reason to believe that your filtration system is either worn or not performing optimally.

6) Air in the System

Sometimes air gets access to the system, and due to this air, your machine starts working abnormally hence loses pressure. Most common reason for this access of air into the system is that the fittings and hoses installed on your machine are not airtight. It can probably occur due to the incompatibility of the hoses installed. 

7) Incompatible Water Temperature

Some of the pressure washers use hot water, and others use cold for performing their duties. The loss of the pressure of your machine can occur due to the usage of incompatible water for your machine, i.e. using hot water in cold water machines or vice versa. This incompatible water can cause your machine to lose pressure.

8) Worn-out Pump

Another reason of your machine losing pressure can be the worn-out pump. With the passage of time, if the pump does not get your required attention, it can worn-out. It is most of the times caused by not changing the oil or using wrong oil or lubricant. It is also caused by lethargy in the inspection of the filtration system, which results in an access of dirt to the pump, and hence your machine loses pressure.

9) Engine Problems

Sometimes the engine of the machine is not optimally working. It results in the decrement of the output pressure. You can make sure, if your engine is working properly, by throttling it up without connecting the hoses. If it is unable to throttle, then it is apparent that there is a problem with the engine of your machine. 

10) Common Hose Problems

The foremost thing to check, if your machine is not working properly, is the hoses attached to it. Sometimes the hoses are incompatible, and the dirt may clog them as well. This dirt stops the easy passage of water hence plays a vital role in decreasing the pressure of your machine.

11) Inlet Water Filter Issues

Sometimes your machine loses pressure due to the clogging of water inlet filter. If the water inlet filter is clogged, it will obviously result in the abnormal working of your machine, and one of those abnormalities is that your machine will lose pressure.

How Can You Prevent Pressure Washer Losing Pressure?

Whenever a problem arises, everyone starts to think how to resolve it. Well, in the matter of pressure problems of your pressure washers you can resolve or even prevent those problems by having a look at the following part of the article. Let’s see the rectification of the issues described above, shall we?

1) Compatible Hose

If you are changing the hose provided with the machine with a new one, you should be looking forward towards the compatibility of the newly purchased hose with your machine. Most of the times the hoses purchased are wider than required. Even a small fraction of an inch can make the difference, so you are advised to buy a hose with an exactly same diameter like the previous one to save yourself from further trouble.

2) Check Pressure Regulator

You should know that if your machine has a pressure regulator installed instead of an unloader valve, it should be adjusted such as it can allow more water to run through it. More the water, less are the chances of its backflow to the pump and the machine can work optimally.

3) Adjust Unloader Valve

The unloader valve bypasses the water and helps in controlling the pressure. You should adjust the unloader valve in small increments so that pressure could be prevented from building too high, which can be difficult to handle. Installation of pressure gauge can solve this problem efficiently.

4) Check Nozzles

If the nozzle is bursting unusual spray pattern, it can be evidence that your nozzle is either worn or plugged with dirt. You should have spare nozzles on hand which can come in handy to check that if the problem persists with the changing of the nozzle. If it does, there is probably some other issue. If it does not, that’s the solution. 

5) Inspect Dirt in the Pump

Inline filters should be inspected to check the presence of dirt in the pump. 9 out of 10 times, the problem of low pressure is caused by dirt in the pump. If your pressure washer does not have a filter for the pump, you should install a filter either a pickup end or an inline filter. It will help in preventing the low-pressure issues.

6) Inspection of the System

The damaged or inappropriate hosing sides can result in disturbing the vacuum within the machine and further results in low or sporadic pressure of the machine. So you are advised to check for damages to the hoses. You should also make sure that if you are changing hose, it is compatible with your machine completely.

7) Compatible Water Temperature

You should not use hot water in the cold water pump and cold water in hot water pumps so that your machine could provide you optimal results.

8) Inspect Pump

You should inspect the pump of your machine regularly. This inspection can save your machine from getting worn-out easily. Keep changing the oil from time to time and always use the right oil or lubricant. If the pump is worn, then you should get it repaired by the help of a technician.

9) Inspect Engine

Same procedure like pump should be applied to the engine as well. If the engine is not working properly, there is no way that your machine will provide you ideal results. Keep checking the engine, and if there appears a problem, you should seek the help of a technician to fix it.

10) Check Hoses

The hoses are checked primarily if the machine is losing pressure. Most of the times there is dirt clogging the hoses, which lowers the pressure. You should unclog it to get back to the prime pressure of the machine.

11) Check for Inlet Water Filter Issues

If inlet water filter is clogged, you should remove the filter and then rinse it out in warm water so that unit again starts reaching the high pressures.


The pressure washers are exciting prospects for a clean and healthy environment. If it is not working properly, you cannot get the best results out of it.

Machines are like people. They also need a proper check-up from time to time to work according to their potential. If that checkup is not performed, the machines will not work properly, and it’s only the matter of time they would get expired. Therefore, to keep them in working condition you should take good care of them. As a result, they will take care of you by providing extremely beneficial outcomes in the end.


Hi, I'm James. The Chief Editor at PressureWasherHub.com. I worked in Pressure Washer industry for a few years, and I thought to share my knowledge about pressure washer on our blog with my team.

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