Pressure washing looks simple enough from the outside, but a DIY attempt can go wrong in a lot of ways. Here are the mistakes that come up most often, and what to do instead.
1. Skipping Protection
High-pressure water can cause serious injury — it can even cut skin at high settings. Wear protective gear, including goggles and closed-toe boots, and protect your surroundings too: move furniture out of the way and cover or wet down nearby vegetation, since cleaning detergents can damage plants.
2. Using Too Much Pressure
Every material has a correct pressure range. Wood and aluminum need a lighter setting, while concrete and asphalt can handle more. Start on the lowest setting on a small test area and increase gradually rather than guessing.
3. Using The Wrong Nozzle
Narrower nozzles concentrate more force in a smaller area, which is good for stubborn grime but risky for general cleaning. A wider, fan-style nozzle is the safer starting point, especially before you're familiar with how a surface responds.
4. Spraying At The Wrong Angle
Siding has openings at the bottom, so spraying upward can force water into the wall and cause flooding or mold. Use an extension wand angled downward when working on tall surfaces instead of aiming the wand upward from below.
5. Cleaning In The Wrong Order
Always start at the roofline and work down — cleaning bottom to top just means dirty runoff re-soils the surfaces you already cleaned. Roofs need special caution too, since not every roofing material can handle direct pressure.
6. Skipping Detergent
Water pressure alone often isn't enough for a deep clean. The right detergent, applied and given time to work before rinsing, makes a real difference — and oil or grease stains typically need a dedicated degreaser.
7. Using A Gas-Powered Washer Indoors
If you ever pressure wash an interior space, stick to an electric unit. Gas-powered washers give off carbon monoxide, which is dangerous without proper ventilation.
8. Washing Surfaces That Can't Dry Properly
Not every surface should be pressure washed with cleaning solutions — materials like fabric or drywall don't dry as quickly as others and can develop mold before they're fully dry.
9. Using Heated Water On Delicate Surfaces
Power washing with hot water works well on tough commercial surfaces, but residential exteriors and furniture are often not built to handle it, and heat can cause warping or damage.
The Safest Way To Avoid These Mistakes
Knowing what to watch for helps, but the most reliable way to avoid these issues is to bring in a professional pressure washing service that already knows how to handle the pressure, angle, and technique for each surface.