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What PSI to pressure wash a house with vinyl siding

Updated September 18, 2026

For vinyl siding, a home electric washer rated around 1,500 to 2,000 PSI with a 25 or 40 degree tip is plenty. The bigger risk is the angle, not the pressure. The Polymeric Exterior Products Association says a power washer can be used with caution: hold it straight at eye level, keep away from openings, and check your siding maker's rules, since some limit the PSI and some say not to power wash at all.

Why the angle matters

Vinyl panels overlap like shingles, lower edge over upper. Spray pointed upward drives water behind them, where it can sit against the wall. Spray aimed level or a little downward runs off the way rain does.

How to wash siding

1. Close windows and cover outdoor outlets, lights and vents. PEPA warns to be careful around windows, doors, wiring and plumbing.
2. Look up your siding brand and check its care instructions for a PSI limit.
3. Apply a house wash soap with the soap tip, working from the bottom up so it does not streak.
4. Rinse from the top down with the 25 degree tip (often green), held level, starting a few feet back.
5. Use the 40 degree tip (often white) near trim, light fixtures and anything loose.

Kärcher's soap FAQ says there is no minimum PSI or GPM for its detergents, so a small machine can still lay down soap.

Second story walls

Do not climb a ladder with a pressure washer. The kick of the wand can push you off balance. Use a soap tip that reaches, an extension wand made for your machine, or hire it out.

Which of our picks fit siding

• Westinghouse ePX3500: 2,400 cleaning units and a 20 oz soap tank. The catch is no 40 degree tip in the box.
• Sun Joe SPX3000: 2,436 cleaning units, the 25 and 40 degree tips, and two soap tanks, so you can keep house wash in one. The catch is a 20 ft hose, which means moving the machine more often around a house.
• Karcher K1700: 2,040 cleaning units, the mildest pick, with a 0.5 gallon detergent tank. Owners mention using it on soffits. The catch is no 25 or 40 degree tip listed.

Check any listing's numbers with the cleaning units calculator, or see all five machines on our picks page.

Never spray an outlet, meter, light fixture or the washer itself. Keep plugs off wet ground.