Best Pressure Washer for Fences: The Mold Battle
Mold on a fence is a different animal than a dirty driveway. Driveway grime sits on the surface. Mold digs into wood grain, and if you don't kill it at the root, it's back in six weeks looking like you never touched it. I've spent 12 years cleaning fences for clients who let theirs go for years, and I've learned that the washer you pick matters less than the nozzle and chemical strategy you bring. But the washer matters. A weak unit turns a two-hour job into a full Saturday.
I'm Tony. I run a mobile detailing business out of a Sprinter van with Rosie, my 70-pound lab mix, riding shotgun. I've pressure washed more cedar, pine, and vinyl fencing than I can count, and I've killed three cheap washers learning what actually holds up. Here's what I'd buy for fence work, what I'd skip, and why GPM matters more than the PSI number on the box.
| Product | Price | Why it won | Why it lost |
|---|---|---|---|
 Simpson Megashot 3200 (B004MXKUCY) |
~$450 | Honda engine, CAT pump, 2.5 GPM cleans mold fast, detergent system actually works | Stock hose is short, wheels are cheap |
 Sun Joe SPX3000 (B00CPGMUXW) |
~$120 | Cheap entry point, detergent draws well, fine for light fence work | Axial pump dies after 2 years, too slow for long runs |
| Ryobi 2300 Gas | ~$299 | Starts and runs, decent pressure for the price | Hose kinks, pump is meh, wheels useless on grass |
 Kärcher K5 (B01BMETENG) |
~$300 | Good pressure for electric, great customer service | Plastic gun feels like a toy, fittings are cheap |
 Westinghouse 2500 |
~$350 | Quiet, reliable, better build than price suggests | Not the most powerful, hard to find on sale |
Why you should trust me
I've owned three pressure washers that taught me what's worth money and what's a ~$150 lesson in frustration. My first was a ~$99 electric that stripped a plastic gear on the third use. I still have the piece. I ran a gas Ryobi for two years that did the job but made me curse every time I dragged it out. For the last four years I've run a Simpson Megashot with a Honda engine that starts first pull even after a winter I forgot to winterize. That was a ~$150 pump replacement I don't want to talk about. I've cleaned more fence panels than I can count, and I've tested every one of these units on actual fence work, not just concrete.
How I picked
Fence cleaning is about three things: enough pressure to strip mold without gouging wood, enough flow to rinse the gunk away, and a detergent system that actually draws soap. PSI is penetration. GPM is what carries the mold off the wood. A 2000 PSI unit with 2.5 GPM will clean a fence faster than a 3200 PSI unit with 1.5 GPM, because the water volume does the work. I looked for units with at least 2.0 GPM, a pump that won't die after one season, and a siphon tube that doesn't stop drawing soap after ten minutes. I also checked what real owners report about long-term reliability, because a fence job takes hours and you don't want the pump blowing a seal halfway through.
I tested each unit on actual fence panels: cedar, pine, and vinyl. I timed how long it took to clean a six-foot section, how well the detergent drew, and how the unit felt after 30 minutes of continuous use. I also measured the stock hose length and noted whether it kinked. Then I checked buyer reports to see if my experience matched the pattern.
Our pick: Simpson Megashot 3200 PSI (B004MXKUCY)
This is the one I tell everyone to buy. The Honda GC190 engine starts first pull every time, even after sitting in my van for months between fence jobs. The CAT pump is what the pros run, and mine's been going for four years without a hiccup. At 2.5 GPM, it strips mold off cedar in a single pass where cheaper units need two or three. The detergent system actually draws soap, which is rare. I've had ~$500 units that stop siphoning after ten minutes. This one pulls the full bottle without complaining.
The stock hose is passable, not great. It's 25 feet, which means you'll be moving the unit around a lot on a long fence line. I replaced it with a 50-foot Flexzilla and never looked back. Budget ~$60 for that before you even think about the washer itself. The wheels are also a bit cheap. On gravel or rough ground they'll catch and wobble. But you're not buying this to race it, and the engine and pump are what matter.
If you're cleaning a fence more than once a year, or if you've got more than 100 feet of fencing, this is the unit. It'll last you a decade if you winterize it. That's ~$45 a year for a washer that makes fence work easy. The ~$120 Sun Joe that dies in two years is ~$60 a year and it'll take you twice as long on every job. Do the math.
Flaws but not dealbreakers
The stock hose is too short and the wheels are cheap on gravel. Both are fixable. The hose is a ~$60 upgrade you'll want anyway. The wheels are annoying but not broken.
Budget pick: Sun Joe SPX3000 (B00CPGMUXW)
Everyone starts here. It's ~$120, it works, and it'll die after two years. But at that price, you got your money's worth. The reviews are full of people saying "great for a patio, garbage for a driveway," and that's exactly right for fences too. It's an electric unit with an axial pump, so you know the deal. The pressure tops out around 2030 PSI and it flows 1.76 GPM, which is light for fence work. You'll be there longer, and you'll need to be careful with the 25-degree nozzle so you don't gouge the wood.
The detergent system on this one actually works, which is more than I can say for some ~$500 units. The siphon tube draws soap consistently, and the onboard tank holds enough for a good stretch of fence. The hose is 20 feet and it's manageable, but you'll be moving the unit around. The plastic fittings where the hose meets the gun are a weak point. One owner in March wrote: "Plastic connector cracked after three months." That's the pattern.
If you've got a small yard, a 50-foot fence, and you're only doing this once a year, the Sun Joe is fine. It's a disposable tool. You'll get two seasons out of it and then you'll buy something better. Some people are fine with that. I'm not, but I understand it.
Flaws but not dealbreakers
The axial pump is a countdown timer, and the plastic fittings will crack eventually. But at ~$120, you're paying for two years of light use, not a decade of heavy work.
Runner-up: Westinghouse 2500
Surprisingly good for the price. Quiet, starts easy, decent pressure at 2500 PSI and 2.1 GPM. The build quality is better than the price suggests, with a brass pump and solid frame. The reviews call it "a sleeper," and that's accurate. It's not the most powerful unit I've tested, but it's reliable and the detergent system draws soap without fuss.
The downside is availability. It's not on every shelf like the Ryobi, and when it goes on sale it sells out fast. If you see one on sale, grab it. At full price it's a tougher call against the Simpson, but if you catch it under ~$300 it's a steal for fence work.
This is for the homeowner who wants something reliable without paying Simpson money, and who doesn't want to fight a kinked hose or a dead pump in year two.
Skip it: Kärcher K5 (B01BMETENG)
Overpriced for what you get. The reviews say "the plastic gun feels like a toy," and they're right. It's got good pressure for an electric at 2000 PSI and 1.4 GPM, but the GPM is the problem. At 1.4, you're going to be on that fence for hours. The fittings are cheap and the wand rattles. Customer service is great, but you shouldn't need to call them.
One verified owner wrote in January: "The gun cracked and leaked after two months." That's the pattern. The K2 is a toy. The K5 is where it gets real, but "real" for Kärcher is "fine for a homeowner who doesn't know better." If you're going to spend ~$300 on an electric, get a Ryobi with better ergonomics or just save for the Simpson.
This is for someone who values customer service over reliability, and who doesn't mind replacing a gun that feels like it came from a cereal box.
Skip it: Ryobi 2300 Gas
Home Depot special. It's the washer everyone buys because it's on the shelf and it's the right price. The reviews are mixed, and "fine if you're not a heavy user" is the consensus. The pump is meh, the hose kinks no matter what you do, and the wheels are useless on anything but flat concrete. But it starts, it runs, and it'll get your fence clean if you're patient.
My first gas unit was a Ryobi, and it did the job. I just got tired of fighting it. The hose kinking meant I was constantly stopping to straighten it out. The wheels caught on every bump in the yard. The pump sputtered on hot days. It worked, but it made me curse.
If you're on a budget and you know you'll only use it a few times a year, it's fine. But if you're going to use it more than that, save for the Simpson. The ~$150 difference is the difference between a tool and a frustration.
The competition
The Generac units are a hard pass. The reviews say "parts are impossible to find" and "the pump died, they quoted me ~$200 for a new one, threw it in the trash." There's no reason to buy a Generac when Simpson exists. The mid-range electrics from Craftsman and DeWalt have the same axial pump problem as the Sun Joe, but they cost twice as much. The Honda-powered units from Simpson and Westinghouse are the only ones I'd trust for fence work, because fence cleaning is a soak-and-rinse job that takes time, and you need a unit that won't quit halfway through.
The bottom line
For fence work, the Simpson Megashot is the unit I recommend to everyone. It's the sweet spot between price and reliability, and the 2.5 GPM makes short work of mold. The Sun Joe is fine if you're on a budget and you know you're buying a disposable tool. Everything else in the mid-range is either overpriced, underpowered, or both.
Winterize your unit. Run antifreeze through it before storage, or plan to replace the pump come spring. There's no third option. And buy a surface cleaner before you even think about the washer itself. It'll turn a six-hour fence job into a thirty-minute one, and you'll feel like an idiot for not buying it first.