Can You Use a Pressure Washer with Low Water Pressure?

Discover the surprising truth about using a pressure washer with low water pressure. Get the answers you need to avoid costly mistakes and make your cleaning tasks easier than ever before!

There is a lot of misconception while looking to purchase pressure washers. Many people think that all they have to figure out is the brand of their liking with the required PSI power. They just have to choose the attachments of their choice, consider the ease of use, and portability; and boom they are ready to order the pressure washer.

Sorry for being a party pooper, but this isn’t enough although you’ve chosen the right pressure washer you shouldn’t opt to buy it without checking the pressure of your water supply. But your chosen pressure washer must be compatible with the pressure of your water supply.

In this article, I will tell you about what is the role of water supply pressure in pressure washers. Moreover, you will also know how to measure the pressure of your water supply.

Role of water pressure in pressure washers:

As stated earlier, you can’t go blindly buying a pressure washer without consulting the pressure of your water supply. Here is why it is too much important to consider:

Pressure washers depend on their GPM value; which is gallons per minute- defining the amount of water flow per minute. If your water supply is lower than the required supply then it may ruin your pressure washer.

Suppose you have a pressure washer with 4 GPM, then the washer will demand the supply to deliver at least 4 GPM or even more. A slight difference may be sufficient to harm the pump of the pressure washer conclusively.

Why low-pressure water supply occurs?

Usually, the main culprit behind low-pressure water in a pressure washer is:


Cavitation is the process in which vapor-filled cavities or air bubbles are produced in the water due to low pressure. there are several reasons why cavitation happens:

  • Vaporization:
  • Air ingestion: air will spread in the inlet and will block the water to flow through it, similar to cavitation bubbles. And will be the reason for decreasing pressure in the pump. You can figure it out with the capacity loss. But it is less severe than vaporization.
  • Turbulence: it happens when water faces irregular fluctuation or mixing in it. Hence, water pressure changes with a magnitude as well as direction

How cavitation affects the water pressure: 

Cavitation causes efficiency and capacity loss. As the cavities increase in the water supply consequently the pressure washer will get louder and noisier; and will produce unusual vibrations. Cavitied water supply will leave the low-pressure area and transmit itself to high-pressure areas, and lead to blasts powered enough to harm the pump of the washer into pieces including metallic portions.

How do measure the pressure of the water supply?

To measure the pressure of the water supply you have to follow a simple procedure.

Method 1:

Take a bucket of 2-gallon water, or more according to your washer GPM i-e: 3-gallon water for a 3 GPM washer, ¾ inches of 25-foot hose connected to tap, and a stopwatch. Open the tap and let the bucket fill. And note the timing using a stopwatch. If the bucket is filled within one minute or at least 3/4th of the bucket it means the pressure of the water supply will be equivalent to or near to washer GPM.

Method 2:

Another simple trick to measure the pressure is, to measure how long it takes to fill a 1-gallon bucket of water. Then divide the number by 60 to have a precise value.  For example, if it takes 30 seconds to fill a 1-gallon bucket, then you will calculate as:

60/30 = 2 GPM

Method 3:

Besides DIYs method, you can take the help of a special tool named a pressure gauge to calculate the pressure of the water supply.  Attach the pressure gauge to the outlet/ faucet, and note the reading from it if it is less than 20 PSI, it is not enough for pressure washers.

Tips and tricks to improve the pressure of water supply:

  • Check for pipes in between the stopcock and the faucet:

If you have a pressure gauge you can check the pressure at the main entrance and your faucet, if there is a difference recorded between both points. It means pipes are clogged or broken in between. By repairing the pipes your pressure will considerably improve

  • Examine the water pressure regulator:

These regulators are often placed near the main stopcock, usually named a pressure-reducing valve. If it is not working properly, it means the pressure of the water will be low.  Measure the pressure with a pressure gauge if the readings come in between 40 to 60, this will indicate good pressure. anything below 20 PSI will be troublesome.

  • Buy a pressure booster pump:

There are multiple pressure boost pumps available in the market and sometimes come with a pressure regulator to set the pressure value of our own choice. These booster pumps are easy to install and increase the pressure compatible enough to use with pressure washers.


Does low water pressure affect a pressure washer?

Yes, low water pressure can have a significant impact on the performance of a pressure washer. A pressure washer relies on a steady and adequate supply of water to generate high pressure, which is necessary for cleaning surfaces effectively.

If the water pressure is too low, the pressure washer will not be able to maintain its pressure so its cleaning performance will be reduced.

What is the minimum water pressure for a power washer?

The minimum water pressure required for a power washer can vary depending on the model and manufacturer. Generally speaking, a minimum water pressure of 1.5 to 2.5 gallons per minute (GPM) and 1000 to 2000 pounds per square inch (PSI) is required for most power washers to function effectively.

Do you need good water pressure to use a power washer?

Yes, good water pressure is essential for the effective use of a power washer. A pressure washer uses a pump to increase the pressure of the water supplied to it, allowing it to effectively clean surfaces. If the water pressure is too low, the pressure washer will not be able to produce the necessary pressure. Therefore, it is important to ensure that the water supply meets the necessary requirements before using a power washer.

Can you use a pressure washer with a bucket of water?

Yes, a pressure washer can be used with just a bucket of water. A pressure washer requires a steady and continuous supply of water, typically from a hose or plumbing system, to function effectively. Using a bucket of water also provide the necessary water supply and the pressure washer will work as intended.


Before buying power tools like a pressure washer, you must go through the checklist to determine which model will suit you the most and whether is it compatible with your scenario. Above in here, I explained what is the importance of the pressure of your water supply is for your pressure washer and how will you determine it through different methods.

If you don’t want to go into too much detail buying a boost pump can cover your bases. Good luck with your shopping now.

Flinn Milan

Flinn Milan is the content director at Washwith. He is responsible for developing helpful content in collaboration with other hard-working team members. Over several years, his content strategy is mainly focused on describing and highlighting every product with its positive and negative points

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