Simpson 3600 PSI Gas Pressure Washer, 2.5 GPM Commercial Power Washer, Cold Water, Honda GX200 Engine, 35' Hose, Aluminum Series…
Best for
Best triplex pump
Amazon rating
Amazon aggregate, one input among many in the Verdict Score
Based on 1 trusted source
Current price
$759.00
Updated Jun 27, 2026 · 1 min read
Sources behind this verdict
10 reviewers weighted by source trust
The consensus
What reviewers found
Synthesized across the trust-weighted source mix below.
The Simpson ALH3425 Aluminum Series earns its spot on pump pedigree. Home Depot verified-purchase reviewers single out the "reliable Honda engine and CAT pump combination," and that CAT triplex pump is the differentiator: across r/pressurewashing, the CAT pump is repeatedly described as more durable than the AAA pumps found on many competing Simpson units. At 3,600 PSI / 2.5 GPM with an aircraft-grade aluminum frame, r/BestPressureWasher describes it as "built to last" and a rare sturdy-but-lightweight combination.
What reviewers liked
- CAT triplex pump praised for durability over common AAA pumps
- Honda GX200 engine and CAT pump combination called out by verified-purchase reviewers
- Lightweight aircraft-grade aluminum frame highlighted by r/BestPressureWasher
Where it falls short
- 2.5 GPM flagged as low for larger surface cleaners in r/pressurewashing
- Among the more expensive residential-class options here
- Competing units match its PSI for less money
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The Simpson ALH3425 Aluminum Series earns its spot on pump pedigree. Home Depot verified-purchase reviewers single out the "reliable Honda engine and CAT pump combination," and that CAT triplex pump is the differentiator: across r/pressurewashing, the CAT pump is repeatedly described as more durable than the AAA pumps found on many competing Simpson units. At 3,600 PSI / 2.5 GPM with an aircraft-grade aluminum frame, r/BestPressureWasher describes it as "built to last" and a rare sturdy-but-lightweight combination.
The honest tension is GPM. On r/pressurewashing, commenters warn that 2.5 GPM is on the low side for running larger surface cleaners ("you need 3+ GPM to reliably run a SC"), so buyers chasing driveway throughput may find it limiting despite the high PSI. It is also among the pricier residential-class machines here, which several owners weigh against lower-cost units that match its pressure.
No independent lab figure for this model appears in the signals, so the verdict reflects converging verified-purchase and specialist-community sentiment rather than a controlled test.
- Simpson Pressure Washer For Professionals
- The Simpson Aluminum Series gas power washer cleans decks, driveways, siding, fencing, equipment, and graffiti; The cold water machine is great for contractors; 49-State Compliant (Not for sale in California)
- Engine & Pump
- HONDA GX200 engine starts easily & includes low-oil shutdown; 3600 PSI 2.5 GPM AAA triplex plunger pump features integrated unloader; Thermal relief prevents overheating; PowerBoost Technology delivers higher pressure at the nozzle
- Long Hose Reach
- The Simpson Morflex series 35' high-pressure hose is non-marring, flexible and abrasion-resistant; Pump/Hose Connection: Threaded M22 connection
- Easy Mobility
- 10" premium pneumatic tires roll smoothly over gravel, grass, and curbs; Balanced layout improves transport; Aircraft grade aluminum frame with powder-coated finish is easy to assemble and resists corrosion; 21" L x 24" W x 34" H; 78 lb.
- Pro Pressure Washer Accessories
- Five quick-connect pressure washer tips (0°, 15°, 25°, 40°, and soap nozzle) cover tasks from stripping paint to car cleaning; Professional QC spray gun with safety lock-out and 16" spray wand included
3600 PSI and 100 dollars cheaper. All these are too small GPM to run any surface cleaners FYI. You need 3+GPM to reliably run a SC. DO NOT ...
I've heard Simpson makes Dewalt washers, Dewalt just slaps a new sticker. So basically boils down to which would be a better buy in terms of psi ...
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