Start with the right pressure and nozzle for your surface

Pressure washers range from 1,300 to 4,000 PSI (pounds per square inch). Most patios—concrete, pavers, or composite decking—do best at 1,500 to 2,500 PSI. Too much pressure cracks concrete, dislodges pavers, and splinters wood. Too little leaves dirt behind. The nozzle matters as much as the PSI: a 0-degree nozzle shoots a tight, powerful stream; a 25-degree nozzle spreads the force over a wider area and is safer for most surfaces; a 40-degree nozzle is gentlest and best for delicate pavers or sealed surfaces.

If you own the patio, test the pressure on an inconspicuous corner first. Rent a pressure washer from a hardware store if you don't own one—they typically cost $50 to $100 per day and come with multiple nozzles. Ask the rental staff what PSI they recommend for your patio material. If your patio is sealed (it will look glossy or feel slick), use no more than 1,500 PSI and a 40-degree nozzle, because high pressure can strip the sealant.

Key Takeaways

  • Use 1,500 to 2,500 PSI with a 25-degree nozzle for most concrete patios; sealed surfaces need 1,500 PSI or less with a 40-degree nozzle.
  • Always test on a hidden corner before washing the whole patio, because pressure and nozzle choice vary by material and condition.
  • Hold the nozzle 12 inches from the surface and move it in overlapping strokes to avoid streaking and uneven cleaning.
  • Protect nearby plants, outdoor furniture, and siding by moving them away or covering them before you start.
  • Let the patio dry fully before sealing it again, which usually takes 24 to 48 hours depending on weather.

Clear the patio and protect what stays

Remove all furniture, planters, grills, and loose items from the patio. Sweep away leaves, twigs, and debris with a broom—this prevents the pressure washer from blasting dirt into the air and keeps the nozzle from clogging. If you have potted plants or landscaping beds at the patio edge, move them back or cover them with cardboard or plastic sheeting. Pressure washers throw water sideways as well as forward, so anything within 10 feet can get soaked.

Check your home's siding, windows, and doors. If they face the patio, close windows and doors, and consider taping plastic sheeting over ground-level vents or AC units. Wet siding can lead to water damage if it seeps behind the boards, and water forced into vents can damage equipment inside. If you have a pool or pond nearby, keep the nozzle pointed away from it—the force can disturb the water and the cleaning chemicals (if you use them) can affect the water chemistry.

Fill the tank and mix detergent if needed

Most pressure washers have a detergent tank separate from the water tank. Fill the water tank with clean water from a garden hose. If your patio has heavy algae, mold, or stubborn stains, add a pressure-washer-safe detergent to the detergent tank according to the product label. Do not use household cleaners or bleach in the detergent tank—they can damage the pump or harm plants and soil.

If you prefer not to use detergent, plain water at the right pressure will clean most patios. Detergent helps with biological growth (algae, mold, mildew) and oil stains, but it adds time because you have to let it sit on the surface for 10 to 15 minutes before rinsing. Start the pressure washer and let it run for a minute to prime the pump before you begin washing.

Wash in overlapping strokes, keeping the nozzle at the right distance

Hold the nozzle 12 inches from the patio surface and move it in slow, overlapping strokes—like mowing a lawn. Overlap each pass by about 6 inches so you don't leave unclean stripes. Move at a steady pace; rushing leaves dirty patches, and moving too slowly can gouge the surface or strip sealant. Keep the nozzle perpendicular (at a right angle) to the surface, not tilted, so the pressure is even.

If you used detergent, spray it on first and let it sit for 10 to 15 minutes. You'll see the algae or stains start to loosen. Then rinse with clean water, using the same overlapping stroke pattern. Work from one end of the patio to the other in a logical pattern so you don't miss spots or re-wash areas. If stubborn stains remain after one pass, let the detergent sit longer or make a second pass—do not increase the pressure or move the nozzle closer, as that risks damage.

Handle pavers and sealed surfaces with extra care

Pavers are more fragile than solid concrete because they're individual units with grout lines between them. Use a 40-degree nozzle and keep the pressure at 1,500 PSI or lower. Move the nozzle parallel to the grout lines rather than directly across them, because high pressure can dislodge the grout or tip pavers. If pavers are loose or the grout is crumbling, pressure washing may make it worse—consider hand-scrubbing those areas instead.

Sealed concrete or composite decking needs the same gentle approach. The sealant protects the material underneath, but high pressure strips it away, leaving the surface vulnerable to stains and water damage. Use 1,500 PSI maximum and a 40-degree nozzle. If the sealant is old and peeling, pressure washing will remove it faster—plan to reseal the patio after it dries. Composite decking (wood-plastic blend) is softer than concrete and can splinter or dent, so stay at the lower end of the pressure range and test first.

Let the patio dry and reseal if necessary

After washing, let the patio dry completely before walking on it or replacing furniture. Drying time depends on weather: in warm, dry conditions, 24 hours is usually enough; in cool or humid weather, wait 48 hours. If the patio was sealed before washing, the sealant is now gone and the surface is porous again. Plan to reseal it within a week while the surface is clean. Concrete sealers, paver sealers, and composite sealants are available at hardware stores and come with process instructions—most are rolled or sprayed on and cure in 24 to 72 hours.

If you didn't use detergent and the patio still has algae or mold spots after drying, you can pressure wash again or explore a mold-killing cleaner and let it sit overnight before a light rinse. Avoid letting algae return by keeping the patio dry and ensuring water drains away from it—standing water breeds mold and algae faster than anything else.

When to call a professional instead

If your patio is very large (over 500 square feet), has delicate or antique pavers, or is severely stained with oil or rust, a professional pressure-washing service may be worth the cost. They have commercial-grade equipment, know the right pressure for different materials, and carry insurance in case something breaks. A professional wash typically costs $200 to $500 depending on size and condition, but it saves you rental fees, time, and the risk of damage.

Also call a professional if the patio has cracks wider than 1/4 inch or if pavers are visibly loose or sinking. Pressure washing can make those problems worse. A professional can assess whether the patio needs repair before cleaning, or they can recommend a contractor who specializes in patio repair.

Frequently Asked Questions

Can I use a pressure washer on a wooden deck instead of a patio?

Wooden decks are softer than concrete and splinter easily under pressure. If you must pressure wash a deck, use no more than 1,200 PSI with a 40-degree nozzle, and keep the nozzle at least 18 inches away. Many deck experts recommend hand-scrubbing or using a soft-bristle brush with a deck cleaner instead, because pressure washing can raise the wood grain and cause long-term damage.

What if the patio has rust stains or oil spots that won't come off?

Rust and oil need chemical treatment, not just pressure. Use a rust remover or degreaser made for patios, explore it to the stain, let it sit for the time the label recommends (usually 15 to 30 minutes), then pressure wash it away. Do not increase the pressure to compensate—the chemical does the work, and pressure just rinses it off.

Is it safe to pressure wash near my house's foundation or basement windows?

No. Water forced under high pressure can seep into cracks in the foundation or around basement windows and cause leaks or mold inside. Keep the nozzle pointed away from the house, and if the patio is directly against the foundation, use a lower pressure (1,500 PSI or less) and a wider nozzle angle. Consider hand-scrubbing the area closest to the house instead.

Do I need to turn off my water main before using a pressure washer?

No, but you do need to connect the pressure washer to an outdoor faucet with a garden hose. Make sure the faucet is turned on fully and the hose has no kinks. If you're using a detergent tank, the pressure washer draws water from the hose, so adequate water pressure is important—if your water pressure is very low, the washer won't work well.

How often should I pressure wash my patio?

Once a year is typical for most climates. If your area is humid or shaded, algae and mold grow faster and you may need to wash every 6 to 9 months. In dry climates, once every 18 months may be enough. Regular sweeping and keeping the patio dry between washes slows the return of dirt and growth.