Pressure washers can be a force multiplier for cleaning around your home or tackling stubborn messes, especially outdoors. However, buyers tend to run into a number of pitfalls when choosing a model, from overestimating how much power they need to missing key configuration details that result in damaged surfaces. Before spending your hard-earned money on a pressure washer, read these five common mistakes and save time, money, and avoid potential damage to your property.
1. Buy for pressure rather than cleaning
Power is important, but it’s not everything. A common mistake new buyers make is prioritizing pressure per square inch (PSI), when in reality, actual cleaning performance depends on a careful balance between PSI and gallons per minute (GPM). An oversized machine can be excessive, depending on how you plan to use it, and it can even be dangerous for cleaning exterior coverings, terraces or vehicles.
Before you buy, think carefully about what you will be cleaning most often and whether you will be using your pressure washer on surfaces that could be damaged or degraded by too much PSI. A small electric unit like our top pick for the best pressure washer, the Karcher K1800PS Cubewill likely be sufficient for cleaning decks, furniture, and light dirt, while heavier jobs might warrant a higher output.
For this type of work, look for a unit that balances 1,500 to 2,000 PSI with around 1.2 to 1.8 GPM. On the opposite end of the spectrum, if you’re looking for serious, heavy-duty cleaning for tough messes, look for a model with 2,800 to 3,500 PSI and 2.3 to 3.0 GPM, something like the DeWalt DWPW3000.
2. Always use the maximum power setting or misjudge the distance
Invest some time in learning the proper tips, angles, and distances when using a pressure washer for different uses.
Steve Conaway/CNETThe temptation may always be to turn your washing machine up to maximum to save cleaning time and ensure you remove all traces of dirt, but as mentioned above, sometimes maximum power is excessive. The same goes for reach: the closer you are to the surface you’re cleaning, the more power you’ll provide. Either way, you risk stripping paint or damaging sensitive exterior details.
The best approach is actually the opposite. Start with your washer set to the lowest possible setting and start near its maximum range, usually about 20 feet or so for consumer models. You can then gradually increase the power and, if necessary, get closer to your target until you clean effectively without damaging the surface. Once again, the choice of model is essential. If you are simply cleaning light dirt on a deck, a smaller device like the Sun Joe SPX3000 packs a lot of punch without risking damage to your property.
3. Ignoring water supply limits
This one is essential to make sure you are right before committing to a purchase. The last thing you want is to bring your new pressure washer home and realize that the flow rate from your home’s hose cannot meet the water demand of the washer. To function properly, the water supply must be able to meet the minimum flow rate required by the pump.
To determine if your supply rate is right, we spoke to Caleb John, manager of Exceed Plumbing & Air Conditioning. He recommends a simple bucket test. Simply grab a bucket of a known volume, like 5 gallons, and a stopwatch (or a phone with a timer app). Fully open the outside faucet or bib, place the hose in the bucket, and time how long it takes to fill it. GPM is the number of gallons in your bucket times 60, divided by the seconds it takes to fill it. So if a 5 gallon bucket fills in 75 seconds, that’s 300÷75=4 GPM.
If your home doesn’t provide enough GPM for the washer you want, you don’t necessarily have to abandon your purchase.
“What you need to do is start by checking to see if your isolation valve opens all the way,” says John. “If not, you may also need to upgrade your water supply pipe to a 3/4-inch diameter. An undersized or restricted pipe starves the pump and wears it out well before its time.”
The type of pump is also a factor, John said. “Fuel pumps require more flow and require a separate supply line. If they run when other devices are running, the pressure drops while working and the pump has to work harder to compensate, greatly reducing its life.”
John told us that in most scenarios, a single washer with pressure between 1,600 and 2,000 PSI should be enough to handle most jobs.
“Units in this range only need 5-6 liters of water per minute, which most standard faucets can comfortably handle. Karcher K5 fits into this and requires no modifications or special requests to the existing supply line, which is exactly why I would direct most homeowners to this solution first.
4. Choosing the wrong nozzle
Using the turbo nozzle in our testing ripped wood to a depth of almost half an inch.
Richard Baguley/CNETChoosing the right nozzle for the job is as important as choosing the right machine for your home. Using the wrong product with an incorrect spray pattern can concentrate too much force on a small area or distribute it unevenly, which can affect the quality of cleaning or the safety of surfaces.
A nozzle tip that is too small can strip paint, pull out wood chips, or even etch softer materials, which is fine if that is your intention, but can be a costly mistake if done by accident. A larger fan is a better choice for general cleaning. Choosing a pressure washer that has a wide array of nozzles means you’ll have more versatility in your cleaning options, so you can adjust whether your machine ends up being more or less powerful than a specific task requires. A versatile washer like the DeWalt 20V MAX 550 PSI Cordless Electric Cleaner Kit comes with a number of nozzle options so you can tackle every task with the right kit.
Choose a pressure washer that has multiple nozzles to give you more flexibility in how you use it.
Steve Conaway/CNET5. Skipping Safety and Accessories
A good pressure washer package will include essential safety equipment and accessories, not just the machine itself. You should include this factor in your price calculations. If you have to buy a bunch of additional equipment after the main purchase, that cheaper device may suddenly not seem like such good value.
Safety glasses, closed-toe shoes, and hearing protection are smart basics, especially with louder gas appliances. You should also consider detergent compatibility, hose length, lance comfort, and storage. A machine that is difficult to use is often misused, leading to poor results or even avoidable damage.
Many pressure washer manufacturers also produce detergents or solutions designed for specific surfaces/materials. There are detergents specifically designed to clean stone, for example, or formulated not to damage softer or finished wooden surfaces. Using the right solution can not only produce better results, but also avoid costly repairs.
To learn more about using your new pressure washer correctly, read our beginner’s guide to pressure washing for expert advice on cleaning all kinds of surfaces around your home.
