Finding the right pressure washer to buy can be overwhelming. There are so many different kinds of washers and each seem to have their own unique feature set. While most people simply narrow their choices down to either electric or a gas pressure washers, there are other criteria that they should look at including a washer’s measured pounds per square inch (PSI) and gallons per minute GPM figures.
PSI gets the most recognition these days between PSI and GPM. It’s what most people and product review sites point to first. However, consideration of a washer’s GPM is just as important. How to choose the right GPM for a pressure washer depends on the size and difficulty of the cleaning job. If you’re working a large area or on really stubborn stains you’ll want a washer that has a high GPM. For smaller jobs or simply cleaning projects a washer with moderate GPM output is sufficient.
This might all seem very general and subjective to the cleaning task at hand. If you’re interested in the specific continue reading on and I’ll share specific scenarios and PSI/GPM metrics are appropriate. Hopefully it’ll all help you determine which pressure washer is suitable for you.
General Overview of GPM Situational Requirements
I’ll get straight to the point for those looking for answers to specific situational pressure washer GPM requirements. Use the table below for quick reference if you’re shopping for a pressure washer for a particular type of job.
Type of Job GPM Amount
|Washing a car or light cleaning||1.5|
|Cleaning sections of your home- home siding, porch or deck, etc.||2|
|Washing off the driveway or cleaning harder to wash parts of the house||2.3|
|Commercially cleaning wood or concrete||2.5|
|Commercially cleaning larger jobs or stripping paint from buildings or houses||3 to 7|
I briefly talked about PSI and GPM. Let me expand on each. Knowing what each term means will help you better understand their relationship with each other and with how they are used with a pressure washer. Keep these definitions in mind when looking at a washer’s product specifications and feature set.
Gallons Per Minute (GPM)
When people are referring to a pressure washer’s GPM, they’re usually talking about the number of gallons of water that is used when the pressure washer is being operated. This is measured per minute.
The reason why a pressure washer’s GPM is so important is because a large amount of water needs to be released from the hose in order to effect certain surfaces. This is because this large amount of water can easily grab the dirt and grime forming on the area you’re cleaning.
Pounds Per Square Inch (PSI)
Similar to the importance of the GPM, pounds per square inch is another term you’ll want to be aware of when purchasing a pressure washer. It indicates how much water pressure is actually being discharged from your pressure washer’s hose. If the water pressure in combination with the amount of water you’re using is high, then you should see the best cleaning results from the washer.
As water is powerfully released using high amounts of pressure, you’ll notice the dirt disappear at a quick and intense pace.
Combining GPM And PSI
Keeping both the GPM and PSI in mind when purchasing a pressure washer is vital to finding one that can perform the most amount of cleaning on the surface. If you have a weak PSI, but strong GPM, or vice versa, you’ll see unimpressive results. For a deeper, more effective clean, try to search for GPM and PSI amounts that go hand in hand.
Cleaning Units (CU)
The final term to keep in mind when you’re finding the best GPM for your pressure washer purchase is cleaning units. In order to find out how effective a pressure washer cleans, you’ll need a way to determine how well GPM and PSI are working together to provide a strong cleaning level. You can measure the power of both the PSI and GPM by multiplying them to get the CU amount.
This is normally used when deciding what kind of strength you want your pressure washer to have. For the best heavy duty pressure washer cleaning effect, you’ll want to purchase a pressure washer with high cleaning units. If you are tackling smaller residential duties, you only need a pressure washer with lower cleaning units.
What Type of GPM Do I Use On Concrete Like My Driveway?
Your driveway and other concrete areas can build up various types of dirt, grime, and stains throughout the day. This makes a large majority of the dirt and stains located on your driveway extremely tough to remove. Many people find little to no luck removing these stubborn particles from the concrete areas using a basic residential pressure washer.
This is why many people will purchase a pressure washer with a GPM of around 1.5 to 2 in order to tackle this giant amount of dirtiness on their concrete area. Many people see more success using these pressure washer types as they will be more effective on harder surfaces such as concrete.
Your driveway will look as good as new after you’ve used a washer with the appropriate amount of GPM levels. To add some extra clean, sparkle and shine, you can add a pressure washer-safe soap or detergent in the water. This can better help remove mildew or other unclean spots off your driveway.
What GPM Should I Use To Pressure Wash My House?
It’s important when properly cleaning your home that you make sure you’re using the appropriate amount of PSI and GPM levels. If these levels are too intense, it could result in potentially breaking a window or part of your door.
More dirt than you may realize can collect alongside your house. This is why a lot of people turn to pressure washers to give a more quick and efficient cleaning experience. You can see your house looking spotless and free after using a pressure washer to clean your home.
Make sure you’re not using the pressure washer on lead paint. These toxic chemicals can be extremely harmful if ingested by you or the other residents of your home.
If it’s only dirt you’re trying to remove from the side of your home, wash it with a power washer that has 2.3 GPM. Any pressure washers with a GPM lower than that won’t be able to successfully remove the dirt from the home. Instead, you’ll just see the dirt merely be moved around rather than completely removed.
If you’d like to increase your chances of removing tougher spots of mildew or dirt, you can add pressure-safe detergent to the water. This helps provide more of a deeper clean on the house. Don’t just add regular dish soap to the pressure wash water. It’s not safe for a pressure washer and won’t provide any type of clean look to your home.
Staying Safe With A High-Pressure GPM
As I’ve mentioned earlier, pressure washers are very strong and contain a bit of a kick when using them. It can end up harming or injuring someone who has never used a pressure washer before. There are several other ways a pressure washer containing a high-pressure GPM can possibly harm someone. Here are a few tips to follow in order to remain safe while using a pressure washer.
Turn off electricity when using a pressure washer.
When operating a power washer, a large amount of water will be used. This is why you’ll want to keep this away from different electrical outlets, power lines, and any other type of electric source nearby. If the electricity and water touch, the intense shocks could critically injure you.
Place both feet firmly on the ground when operating a pressure washer
Depending on the GPM and PSI levels in your pressure washer, there can be a great deal of pressure coming out of it.
To prepare for this, keep both feet on the ground and stand tall. Get ready for a large amount of pressure to come exploding out of your washer. Use both hands while operating.
Stand a safe distance from your target
When using the pressure washer, you’ll want to prepare yourself for a lot of pressure. If too much pressure and water hit all at once, your target area could become damaged.
Stand far away and point the power washer at the section you want to clean. Once you get used to the flow and distance, you can keep inching forward more and more for a more targeted clean.
Pressure Washer Categorization
Now that you know what goes into finding the best pressure washer and GPM, we can dive into the different types of pressure washers that are available. They are all separated and categorized according to the amount of PSI and GPM they both contain.
Electric pressure washer
This pressure washer will contain a fairly low PSI, so it is considered the best pressure washer to use on smaller objects or lighter tasks. Here are a few of the items that can be best cleaned with an electric pressure washer with a lower PSI and GPM:
- Furniture on your porch or patio
- Car tires
- Grilling equipment
- Inside of your garage
This type of pressure washer is usually smaller than most. Many find that little to no maintenance or upkeep needs to be completed on these pressure washers. This is because they are known to last a long time and don’t often break easily. They’re quieter than most of the other pressure washers available. So, you won’t have any worries about disturbing the neighbors.
Since this is an electric pressure washer, it requires an extension cord. Constantly plugging and unplugging this cord may make it more difficult for you to move about and wash various areas at a time. This is also why people will prefer to use this pressure washer primarily for smaller tasks.
It will take a lot longer to complete various larger tasks if you decide to use this pressure washer for anything other than residential cleaning.
You’ll normally find an electric pressure washer containing around 500 to 5000 PSI. The GPM for these pressure washers is anything between 1 to 4. This type of GPM and PSI is perfect for smaller items. If you try to use any pressure washers with a stronger GPM and PSI, you could end up hurting the items you’re trying to wash.
Residential pressure washers
These washers are powered specifically by gas rather than electricity. If you have anything on or outside of your home that needs washing, this is the tool to use. You’ll want something with a good amount of water coming out of it in combination with strong pressure. Below are the different items and areas you can use these washers on:
- Your porch or deck
- The outside area of your house
- Your home’s driveway
- Your doors and windows
When you’re searching for a residential washer powered by gas, you’ll normally find them with a PSI of around 3000 to 4000. The GPM will also be around 1 to 3. These are perfect to use if you need to clean or work on different larger projects around your home. You’ll find that this type of pressure washer will work at a medium level of pressure and water.
If you use a larger amount of PSI and GPM on these areas, you may run the risk of washing these items too strongly or intensely. As a result, your personal items or house could risk being damaged from the water intensity. If it doesn’t have enough PSI and GPM, it may barely wash it at all, or it could take too long to wash it.
The only problem with this type of unit is that it requires gas. Because of this, the gas will emit carbon monoxide, which can become extremely harmful to someone if too much of it is inhaled. This is why you don’t want to use this type of power washer if you are washing anything inside of an enclosed area, like a shed.
Try to only wash outside areas around your home and don’t breathe in too much of these harmful chemicals.
Commercial pressure washer
If you need to complete an extremely large cleaning project, consider purchasing a commercial pressure washer. This type of washer normally won’t be used in residential areas or on smaller objects around your home.
Commercial pressure washers are normally used by cleaning professionals who need to clean different areas like office buildings and large windows.
You will want to refrain from using a washer this powerful on smaller cleaning projects like cleaning different sections of your home. Since these consist of a PSI of anything from 2000 to 8000, it can be extremely powerful. The GPM of this type of pressure washer can be up to 10 GPM.
There are many circumstances where you wouldn’t want to use a pressure washer with as much kick as this one. If you do, you may have some issues as it can be too powerful or strong for someone to use if they have never used a pressure washer before. Additionally, it can also cause damage to the item or surface that you’re cleaning.
Utilizing a pressure washer properly isn’t an easy task. This is why it’s advised to start with a residential or electric washer rather than one commercially made.
These contain a higher PSI and GPM that make them harder for beginners or even the average residential users to wash with.
Both the pump and engines are considered to be professional material. This means that it is mainly used by workers who wash windows and the exterior of buildings every day. They are built to last for all hours of the day.
Because of this, you’ll find that many of these pressure washers are quite expensive and trickier to use than those built for residential use.
Classifications of Pressure Washers
In addition to the different categories that these pressure washers fall under, you’ll also notice they consist of three basic brand types. Each of these pressure washer levels are made to complete specific types of cleaning projects. Deciding which is best for you to use will be dependent on what exactly you need cleaned and how quickly it needs to be done.
Consumer pressure washer
These washers are made specifically for those who hold little to no pressure washer experience. If you’re buying your first pressure washer to complete smaller cleaning tasks around your home, this is a great one for you to start out with.
The pump and engine on the pressure washer are designed to be used every so often. If you’re hoping to wash several items almost every day, don’t consider this pressure washer. It wasn’t made to be used too often throughout its life, so you may want to stick to only using it every few months.
Semi-pro pressure washer
Once you’ve regularly used a basic pressure washer around the house for a while and want to complete larger cleaning projects, you could be ready for a semi-pro pressure washer. The higher GPM and PSI of these washers make exterior cleaning quicker and less of a hassle. This washer is used to clean larger items around your house that can’t be as easily washed with only a consumer pressure washer.
These contain a professional pump as well as an engine that are both designed specifically for homeowners to use. They are also available with an engine made for a professional and a pump made for the consumer. This is why this pump is perfect for someone who has some experience using a pressure washer but doesn’t quite yet consider themselves a professional.
The engine and durability of these washers weren’t designed to handle professional or commercial use, so they won’t last long if you use them every single day. It was designed primarily to help you complete larger cleaning tasks around the house once or twice a week.
Purchasing A Nozzle To Make Your Pressure Washer More Powerful
Some people may be looking to give their home a deeper wash, but they don’t find the highest level of residential power washers to be powerful enough. Since commercial or semi-pro pressure washers are harder to use and more expensive, many settle with their basic pressure washers.
Sticking with a basic pressure washer still provides a hassle for users, as it takes longer for them to efficiently clean larger items. There are different ways to make your pressure washer become more of a powerful tool without having to upgrade to a professional or commercial washer.
You can buy a nozzle that can spit out different types of water streams by changing how narrow the shape is when it comes out. The nozzle can make the water come out in more intense streams that make washing your desired objects less time-consuming.
When measuring how forceful the water comes out of the pressure washer nozzle, people will use a scale of 0 to 40 degrees. A pressure of 0 degrees is the narrowest option and contains the most force. A pressure of 40 degrees is the least amount of force and is known to be the gentlest spray.
Many people advise against purchasing a nozzle and shooting it at 0 degrees. This is way too powerful for average items to withstand. This can shatter glass or damage the objects you’re trying to clean, which could harm you or others standing nearby. When it comes to using 0 degrees, the force may be too strong with this one.
Try to use the lowest setting on your nozzle, then gradually work your way up as you become more comfortable. The amount of force that comes out of your nozzle will become greater and greater as the numbers increase, so take your time working your way up.
You’ll also want to use the nozzle on the lowest level and try it out on different areas before you crank it up to the highest degree. Some of your items have the ability to withstand an intense amount of pressure, while others are too fragile to handle a high degree of pressure. Be cautious with this.
What Type Of Water Can I Use In My Pressure Washer?
You’ll want to use your garden hose in order to fill the pressure water up the recommended amount. Be sure to clean your water filter to rid it of any unwanted debris or other objects floating in the water. The water you use in the pressure water has to be clean, filtered water.
Water used from a pond or a lake could damage the pump on your washer. This pump and the pressure washer aren’t properly designed to handle too much debris getting trapped inside. The water coming out of this machine needs to be properly cleaned and ready to spray out of the nozzle.
Make sure you’re filling the pressure washer with the correct amount of water according to the amount of GPM levels written on the washer. If that amount isn’t reached, then you could risk harming or damaging the pump further as it needs that amount of water to work properly.
Refrain from adding any water temperature other than cool water. There are different areas inside of the pump called o-rings. If hot water hits these rings, it can start to damage them which can further damage the pump’s performance.
Can I Use My Pressure Washer In The Winter?
Winter is usually the season favored the least by many pressure washer operators. The water inside of the pressure washer needs to remain cold to operate. This makes cleaning in the winter extremely unbearable. No matter the weather, the dirt will still build up on your home. So, using the pressure washer in the wintertime is still necessary and can be done.
Try not to use a large amount of pressure on any of your items in the wintertime. This can end up hurting certain areas of your home, such as windows and doors. Check your pressure washer to see if you’ll be able to use antifreeze in conjunction with the water. Some will allow you to do this, making it easier to use the high pressure water in the cold.
If you can, try to use the washer on days that are sunny and not windy or extremely cold. Your washer pressure is only built to work in higher temperatures. Sometimes the need to have your house washed in the winter is necessary, though. So, some are built for times like these.
When picking the GPM levels that work best with your pressure washer, you’ll have to focus on exactly what you need it for. Try to find lower GPM pressure washers and use that on small household objects around your home.
As the project gets larger and tougher, you may need to find a pressure washer that offers a higher GPM. Try your best to stay safe when using higher GPM and PSI levels as they can sometimes be a lot stronger than you may expect.