How to Clean a Wood or Vinyl Fence with a Pressure Washer

I Learned This the Hard Way

I bought my first pressure washer five years ago. A gas-powered 3100 PSI brute. I hooked it up, pointed it at my cedar fence, and pulled the trigger. Within thirty seconds I had carved a groove clean through two boards. My wife came outside and just stared at me. That fence cost me $800 to replace. I’ve since cleaned dozens of fences for friends, family, and neighbors. I have a box of ruined nozzles and a lot of scarred wood to prove it. Here’s exactly what worked—and what didn’t—so you don’t have to learn like I did.

What You’ll Need

Don’t skip anything on this list. I did. I regretted it.

• Pressure washer: 1500–2000 PSI for wood fences. 2000–2800 PSI for vinyl. Anything above 3000 PSI on wood is asking for trouble.
• Wide-angle spray tip: A 40-degree or 25-degree tip. Never a zero-degree or turbo nozzle. I destroyed a board with a turbo nozzle in three seconds flat.
• Fence cleaner or wood stripper: I use Thompson’s WaterSeal Fence Cleaner (about $15 at Home Depot). For vinyl, Simple Green works fine.
• Garden sprayer: A 2-gallon pump sprayer ($20). Much easier than mixing in the washer’s soap tank.
• Bleach or oxygen bleach: For killing mold and mildew. I mix 1 cup of oxygen bleach per gallon of water.
• Soft bristle brush: A long-handled brush on a pole. Let’s you scrub without leaning into the spray.
• Safety glasses and closed-toe shoes: One ricochet off a fence board into your eye will convince you.
• Drop cloths or plastic sheeting: To cover plants, grass, and stone pavers. The chemicals will kill your petunias.

Prep Like Your Fence Depends On It

I once skipped the prep and sprayed cleaner straight onto a fence that had bird nests in the posts. I flooded a finch family. Felt terrible. Here’s what I do now:

1. Water down the ground at the fence line. Wet grass and soil absorb the cleaner better. Prevents runoff from killing roots.
2. Pull back plants and cover them with plastic. I use cheap painter’s drop cloths. Weigh them down with bricks or rocks.
3. Scrape off loose paint or flaking stain. A plastic putty knife works. Don’t use metal—it gouges wood.
4. Spray the entire fence with plain water first. Wet wood won’t soak up as much cleaner, and it makes the pressure wash more even.

Cleaning a Wood Fence: Step-by-Step

Step 1: Apply cleaner. Fill your garden sprayer with the cleaning solution. Spray it on the fence in 4-foot sections. Let it sit for 10 minutes. Don’t let it dry out. If the sun is hot, work in the shade or mist the fence with water after 5 minutes.

Step 2: Scrub stubborn spots. For green algae or mold patches, hit them with the soft brush and some extra cleaner. I spent 20 minutes scrubbing a single panel covered in moss. Worth it—the pressure wash afterward looked perfect.

Step 3: Pressure wash at the right distance. Stand 18 to 24 inches away. Hold the wand at a slight angle—about 45 degrees. Sweep the spray in slow, even passes. Overlap each pass by about half. If you see the wood starting to fuzz or splinter, you’re too close. Back off. A light gray streak means you’re taking off the soft summer wood. That’s bad.

Step 4: Rinse thoroughly. Switch to a 25-degree tip and spray from 12 inches away. Rinse from top down. Push all the soap and dirt off the bottom of the fence. Don’t let it puddle at the base—that’s how you get rot.

Mistake to avoid: I once pressure washed a pressure-treated pine fence while it was still wet with rain. The water trapped the dirt deeper into the grain. It looked worse than when I started. Always clean on a dry, low-humidity day.

Cleaning a Vinyl Fence: Easier but Still Tricky

Vinyl is forgiving but not indestructible. I’ve seen guys shoot a hose straight into a vinyl panel and crack it like a dinner plate.

Step 1: Use lower pressure. 2000 PSI max. I set my machine to “low” or use a 40-degree tip. Vinyl doesn’t need the muscle.

Step 2: Skip the harsh chemicals. Vinyl hates bleach. Use dish soap and water in your sprayer (2 tablespoons per gallon). I’ve used Spray Nine (about $8 a bottle) for heavy mildew. Works like magic.

Step 3: Spray straight on, not at an angle. If you angle the spray, you can blast water under the slats or into the post caps. That blows out caulking and loosens the panels. I did this to a neighbor’s fence and had to replace three caps.

Step 4: No scrubbing needed. Just let the soap sit for 5 minutes, then rinse. If there’s dirt stuck in the texture of the vinyl, use a sponge. Not a brush. A stiff brush will fog the finish.

What to Do After (Don’t Skip This)

Let the fence dry completely. Wood fences need 24 to 48 hours of dry weather. I check by splashing a little water on it. If it beads up, it’s not ready for sealer. If it soaks in, it’s good. Vinyl needs about an hour in the sun.

For wood fences, I apply a stain or sealer within a week. I like Ready Seal Exterior Wood Stain (about $35 a gallon). It’s thick and doesn’t need a primer. One gallon covers 150 square feet. I roll it on with a 4-inch roller, then back-brush it with a cheap brush to get into the grain.

For vinyl, a clear UV protectant spray works. I use 303 Aerospace Protectant (about $20 a bottle). Spray it on, wipe it off. Keeps the vinyl from fading for about 6 months.

Frequently Asked Questions

Can I use a pressure washer on a fence that’s already painted?

Only if the paint is in good shape. If it’s peeling, the pressure washer will rip it off in sheets. I learned this on a rental house. The whole north side flaked off. I had to sand and repaint the entire section. Test an inconspicuous spot first.

What’s the best PSI for a cedar fence?

1500 PSI. Period. I ruined a cedar board at 1800 PSI. Cedar is soft. Use a 40-degree tip and keep the wand 24 inches away. If the fence is dirty and you can’t get the dirt off at that pressure, use a stronger cleaner. Not more pressure.

How long does it take to clean a 200-foot fence?

About 3 to 4 hours with good prep. That includes setting up, cleaning, rinsing, and drying. If you’re sealing it too, add another 2 hours. I once tried to do a 200-foot fence in one afternoon and ended up working in the dark with a flashlight.

Do I need a surface cleaner attachment?

No. Not for fences. Surface cleaners are flat discs meant for driveways and patios. They’re awkward on vertical surfaces. Stick with the wand.

Will a pressure washer damage my vinyl fence?

Yes, if you’re an idiot like I was. I cracked a panel by spraying too close at 2500 PSI. Keep it at 2000 PSI or lower. Use a 40-degree tip. If you see the vinyl bowing inward, you’re too close or the pressure is too high.

What’s the most common mistake people make?

Using a turbo nozzle. I see people buy them at the store and think they’re magic. They’re not magic. They’re damage machines. A turbo nozzle spins the water in a tight pattern. On a fence, it can strip the paint right off or carve a groove in the wood. Throw that nozzle in your junk drawer and forget about it.

And don’t let your kid or friend “help” without practice. I handed the wand to my brother-in-law once. Within ten seconds he’d shot a trench in a board. Some people just can’t resist the temptation to squeeze the trigger all the way.