Why You Should Think Twice About Building A DIY Pressure Washer

"Think twice" is often thinly veiled code for "run away, far and fast." But if you're in the market for a high-end pressure washer, we want you to take a good look at YouTuber @sixtyfiveford's DIY pressure washer build and think about it in two different ways. He manages to build a top-of-the-line commercial power washer for about half its retail price, and with very little effort. The things you need to be thinking about are whether you can get that price and whether you're equipped to do the job. Spoiler: probably not, and probably.

A pressure washer is a small collection of parts designed to work together... sort of. The core is the engine and the pump. These are usually trucked about on a rolling frame, and have a hose and wand attached to them. They have all manner of PSI, gallons per minute (GPM), and horsepower ratings. @sixtyfiveford is putting together a 4,000 PSI, 4 GPM pump and a 13 HP Honda engine — the sort of specs found on high-end and commercial pressure washers.

@sixtyfiveford spent around $750 on his build, thanks mainly to the $50 used Honda GX390 engine. That model is currently $899.99 new from Northern Tool. We priced out all the parts for this build (except fasteners) and came up with $1884.33. But PressureTek sells a similar pressure washer with the same Honda engine and a comparable Comet Triplex pump for $1329.00 — more than $550 cheaper than we found the parts new. The relevant components include a Cat pump, hose, wand, quick-connect adapters, winterizer, the Honda GX390, and a pressure-washer frame. Like @sixtyfiveford, we included the winterizer because preparing your pressure washer for winter is vitally important.

At these prices, it's a no-brainer: Just buy a new pressure washer instead of building your own. For a DIY build to be cost-effective, you'd probably need to find at least two of the three-figure items (pump, engine, and frame) at a greatly reduced cost. If you're a welder, it should be simple to make your own frame. But that'll only save you $144, assuming you have the materials (steel, wheels, tires, and axles) lying around. Keep in mind that you are building a top-notch power washer; if all you need is a basic consumer model, the cheapest pressure washer at Home Depot can be had for under $100. But if you can also manage to find either the pump or the engine dirt cheap, it's time for that second thought: can you build it?

DIY builds of commercial products are often impractical, requiring knowledge, tools, and facilities that are often out of the question. But because @sixtyfiveford used standard, compatible parts on a salvaged pressure washer frame, assembling the parts was extraordinarily simple. The engine mounts to the frame, and the pump is attached with four bolts and a set screw for the engine's PTO shaft. With these parts, if you can lift the engine into place on the cart, the answer is yes, you can build it yourself.

Perhaps the hardest thing about this DIY, aside from writing the check, is fitting the right pump to your engine. PTO shafts come in three common sizes and either vertical or horizontal orientation. The pumps themselves attach directly to the engine but must have a matching bolt pattern (there are four common three- and four-bolt patterns). And the pump must be matched to the power of the engine. Consult a good fitment chart to make sure your engine and pump are properly paired. And, finally, take a good look at those specs one more time (look thrice?). This is a high-powered pressure washer that might be more than you really need. And if you do end up with a 4,000 PSI machine, pay close attention to all the safety precautions you should take when pressure washing your house.