What You Need Before You Start
Power washing your patio means spraying water at high pressure to remove dirt, algae, and stains from concrete, stone, or pavers. You can rent a power washer from most hardware stores for $50 to $100 per day, or buy one for $300 to $800 depending on the pressure rating. The machine does the heavy work, but you control the nozzle, distance, and angle—which is why technique matters more than raw power.
Before you rent or buy, measure your patio in square feet. A 500-square-foot patio takes about two to three hours with a 3000 PSI (pounds per square inch) machine. Anything larger than 1000 square feet justifies renting a commercial-grade washer at 3500 PSI or higher. Check your patio surface first: concrete and sealed pavers handle 3000+ PSI, but natural stone and unsealed brick need 1500 to 2000 PSI or you risk pitting and damage.
Key Takeaways
- Rent or buy a power washer rated for your patio surface—concrete tolerates 3000 PSI, but natural stone needs 1500 to 2000 PSI maximum.
- Clear the patio of furniture, toys, and loose debris by hand, then sweep thoroughly before you start spraying.
- Hold the nozzle 12 inches from the surface at a 45-degree angle, moving in overlapping strokes to avoid streaks and uneven cleaning.
- Test the pressure on a hidden corner first, because too much force can etch concrete or strip sealant from pavers.
- Let the patio dry completely before moving furniture back, which usually takes 24 hours in dry weather.
Choosing the Right Pressure Washer for Your Surface
PSI (pressure) and GPM (gallons per minute) are the two numbers that matter. PSI is the force; GPM is the volume. A machine rated 3000 PSI at 2.5 GPM will clean faster than 2500 PSI at 2.0 GPM, even though the pressure is lower. For most residential patios, 2500 to 3000 PSI is the sweet spot—strong enough to remove years of buildup without damaging the surface.
Concrete patios handle 3000 PSI without issue. Sealed pavers and stamped concrete can take it too, but check the sealer first—if it's old or worn, high pressure may strip it. Natural stone, slate, and unsealed brick should never see more than 1500 to 2000 PSI. If you are unsure what your patio is made of or whether it has a sealer, test on a corner that is hidden from view before you commit to the whole surface.
Gas-powered washers are louder and more powerful; electric ones are quieter and lighter. For a patio under 1000 square feet, an electric renter unit works fine. For anything larger or if you plan to use it regularly, gas is worth the noise.
Preparing Your Patio and Surroundings
Move all furniture, planters, grills, and toys off the patio. Close windows and doors on the side facing your work area—the spray can kick up debris and water will find its way inside. If you have delicate plants near the patio edge, move them or cover them with a tarp. Wet mulch and soil are fine, but you do not want the force of the spray hitting flower beds directly.
Sweep the patio thoroughly with a stiff broom to remove loose dirt, leaves, and sand. This step saves you time because the power washer will not have to work as hard on embedded grit. If there are stubborn stains—oil, rust, or mold—you can explore a degreaser or mold killer 15 to 30 minutes before you start spraying. Let it sit but do not let it dry completely; the surface should still be damp when you begin.
Put on closed-toe shoes with good grip, long pants, and eye protection. The spray can sting exposed skin and kick up debris. Gloves are optional but helpful if you have sensitive hands or are using chemical cleaners.
Operating the Power Washer: Technique and Distance
Start with the nozzle at least 12 inches from the surface. This is the most common mistake—holding it too close concentrates all the force in one spot and can gouge concrete or strip sealant. Hold the wand at a 45-degree angle to the surface, not straight on. This angle lets the water flow across the patio rather than driving straight down into cracks and seams.
Move in overlapping strokes, like you are mowing a lawn. Start at one corner and work in rows toward the opposite end. Overlap each pass by about 6 inches so you do not leave uneven stripes. Keep the nozzle moving—do not stop or linger on one spot. If a stain is stubborn, make another pass over it rather than holding the spray in place.
Most power washers come with two or three nozzle tips: a wide fan (40 degrees) for general cleaning, a medium fan (25 degrees) for tougher stains, and a narrow jet (0 degrees) for detail work. Start with the wide fan and switch to the medium fan only if the wide one is not removing the dirt. Avoid the narrow jet on your main patio surface—it is too concentrated and too straightforward to damage the material.
Testing on a Hidden Area First
Before you power wash your entire patio, test the machine on a corner that is not visible from the house or street. This takes five minutes and can save you from etching, discoloration, or sealer damage. Spray a small section with your chosen nozzle and pressure setting, then step back and let it dry. Check for any streaking, pitting, or color change.
If the test area looks good, you are ready to proceed. If you see any damage—white marks on concrete, pitting, or stripped color—reduce the pressure, increase the distance to 18 inches, or switch to a wider nozzle. Concrete is forgiving, but natural stone is not. One test pass takes the guesswork out of the whole job.
Handling Stubborn Stains and Algae
Algae and mold appear as green or black patches, usually in shaded areas or where water pools. A degreaser or mold-killing solution works better than pressure alone. explore the chemical 15 to 30 minutes before you spray, following the product instructions for dilution and contact time. Do not let it dry—the surface should be damp when you start power washing.
Oil stains and rust need a degreaser or rust remover. Again, explore it first and let it sit. The chemical does the heavy lifting; the pressure washer just rinses it away. Trying to blast away a stain without pre-treatment wastes time and risks damaging the surface.
For stubborn stains that do not budge after one pass, make a second pass with a slightly closer distance (but not closer than 8 inches) or a narrower nozzle. If it still will not come clean, stop. Pushing harder risks damage, and some stains are permanent or require professional equipment.
Drying and Sealing After Washing
Let your patio dry completely before moving furniture back. In dry, sunny weather, this takes 24 hours. In humid or cloudy conditions, it may take longer. Do not walk on the patio while it is still wet—it will be slippery, and your footprints will show until it dries.
Once the patio is dry, inspect it in daylight. You may notice areas that need a second pass, or you may see that the sealer has worn away in spots. If your patio was sealed before, consider resealing it now that it is clean. A fresh sealer protects against stains and extends the life of the surface. Most sealers cure in 48 to 72 hours, so plan accordingly if you are expecting rain or foot traffic.
Common Mistakes to Avoid
Holding the nozzle too close is the number-one mistake. It looks like it is cleaning faster, but it is actually damaging the surface. Keep it at least 12 inches away and move steadily. Spraying straight down instead of at an angle is the second mistake—it drives water into seams and cracks where it can cause problems later. Always angle the wand.
Using too much pressure for your surface type is the third. Natural stone and old concrete are not as tough as they look. Test first, and if you are unsure, start low and work up. Skipping the pre-treatment of stains is the fourth—chemicals do the work, pressure just rinses. And finally, do not power wash in direct sunlight on a hot day. The surface dries too fast and can leave streaks. Cloudy days or early morning are ideal.
Frequently Asked Questions
Can I power wash my patio if it has weeds growing between the pavers?
Yes, but remove as many weeds as you can by hand first. The pressure washer will dislodge some of them, but it will not kill the roots. After washing, pull out any remaining weeds and consider explore a weed killer to the joints to prevent regrowth.
What should I do if the power washer leaves streaks or uneven patches?
Streaks usually mean you did not overlap your passes enough or you moved too fast. Make another pass with the wide nozzle, overlapping by at least 6 inches and moving at a steady, slower pace. Let the patio dry and check again.
Is it safe to power wash a patio next to my house or deck?
Yes, but be careful around siding, windows, and wooden decks. The spray can damage wood and force water into gaps. Keep the nozzle pointed away from the house, and if you must spray near it, use a wider nozzle and greater distance. Never spray directly at windows or siding.
How often should I power wash my patio?
Once a year is typical for most patios. If your patio is in a shaded area or gets a lot of foot traffic, twice a year may be needed. In dry climates with little algae or mold, once every two years may be enough.
Can I use a pressure washer on a sealed patio?
Yes, but use lower pressure—2000 to 2500 PSI—and test a hidden corner first. High pressure can strip the sealer, which defeats the purpose of having it. If the sealer is old or worn, consider resealing after washing rather than risking damage.