Detailing · pressure washers
The psi on the box is not a measurement.
Pressure washers are sold on one number, and that number is supplied by the company selling the machine. Road & Track says so on the face of its own comparison — the specification table is headed “claimed” and the article states outright that all listed specifications come from the manufacturer. They washed two cars with each unit. They did not put a gauge on the line, and almost nobody does.
The one time somebody measured
Obsessed Garage published a flow and pressure reading taken at the gun, through a 50 ft hose and a swivel spray gun, using the nozzle they recommend for washing a car. A Karcher K1700 delivered 1.1 gpm at 1000 psi under those conditions. Their own summary of the category is blunt: most pressure washers advertise 2000–3000 psi and make nowhere near that in practice.
That is not quite the gotcha it looks like, and the honest version matters. Pressure at the gun is set partly by the nozzle: fit a narrower tip and the same pump reads higher. The manufacturer's headline figure is taken at the pump under conditions favourable to a big number. The 1000 psi reading is what the machine gives you through the tip you would actually point at your paint. Both numbers can be true and only one of them describes washing a car.
This is why the two tables below are not merged into one. They are different machines measured different ways, and putting them in a single column would invent a comparison that nobody performed.
| Product | Pressure psi, claimed marked | Flow gpm, claimed marked | Noise dBA, distance not stated use it | Weight lb use it | Where to buy |
|---|---|---|---|---|---|
| Chemical Guys ProFlow PM2000 Mains. Highest flow of the corded units here | 2030 | 1.77 | 82.1 | 13.5 | Check on Amazon |
| Westinghouse ePX3500 our pick Mains. Quietest in this group | 2100 | 1.76 | 70.0 | 21.0 | Check on Amazon |
| Greenworks GPW2000-1RG Mains. Onboard reservoir doubles as a foam source | 2000 | 1.10 | 84.5 | 30.2 | Check on Amazon |
| Fanttik NB8 Ultra Battery, draws from its own 4 gal tank | 725 | 2.60 | 76.0 | 25.8 | Check on Amazon |
marked Road & Track, Best Electric Pressure Washers for Car Washing in 2026, Tested, August 2025. Pressure and flow as published by each manufacturer. The test states this outright: “all listed specifications are provided by the manufacturer”. The testers washed a Volkswagen Tiguan and a Porsche Boxster with each unit, but did not put a gauge on the line.
use it Road & Track, Best Electric Pressure Washers for Car Washing in 2026, Tested, August 2025. Noise in dBA and weight, recorded by the testers while washing two cars in a driveway. Distance for the noise reading is not stated, so these numbers are comparable with each other but not with a reading taken at a stated distance elsewhere.
Flow is the number to shop on
Washing a car is a rinsing job, not a stripping job. What carries dirt off the panel is volume of water, and what risks the paint is pressure. Road & Track puts the useful automotive band at 1.2–2.5 gpm and warns against going above about 2500 psi on a car at all. Obsessed Garage arrives at the same place from the other direction: as much flow as they can get at around 1000 psi.
We had this page wrong, and the correction is instructive. It ranked these machines on the claimed flow figures above and recommended the Westinghouse for moving “half again as much water” as the Greenworks. Then we read the maker's own page.
Westinghouse publishes two sets of numbers for the ePX3500. The pair the round-up reprinted — and the pair on the retail listing — is 2500 max psi and 1.76 max gpm, with the flow qualified in the maker's own words as at lowest pressure. Separately it publishes 2000 rated psi and 1.2 rated gpm. The max pair cannot happen at once. The rated pair is the machine working.
Scale runs to 1.76 gpm, the highest figure here.
marked Westinghouse, ePX3500 Electric Pressure Washer — manufacturer specifications, read 31 July 2026. The maker's own page publishes TWO pairs of figures: 2500 max PSI and 1.76 max GPM, the flow qualified verbatim as “at lowest pressure”, alongside 2000 rated PSI and 1.2 rated GPM. The max pair cannot occur together; the rated pair is the one that describes the machine doing work.
At 1.2 gpm rated, the gap to the Greenworks' claimed 1.10 is nearly nothing — and the ranking the numbers seemed to support disappears. We could not find published rated figures for the other three machines, only maxes, so the flow comparison this page was built on cannot honestly be made from what any of these makers publish.
That is the finding, and it is worth more than the ranking we replaced. When one manufacturer in a category publishes a rated figure a third below its headline, every unqualified max in that category is suspect, including the ones we reprinted in the table below.
Before you buy: the tap decides
A pressure washer cannot deliver more water than it is fed. If your outside tap fills a 5 gallon bucket in more than about three minutes you are below 1.7 gpm at the source, and a 1.77 gpm machine will starve, surge and cavitate no matter what its label says. Time the bucket before you choose the machine — it is the one measurement on this page you can take yourself, and it costs nothing.
What nobody has measured
We could not find a published test that read pressure and flow at the gun for more than one machine at a time, under one stated set of conditions. That test — same hose, same gun, same nozzle, four machines, a gauge on the line — would settle the category, and as far as we can tell it does not exist. Every ranking of these units, including ours, is reasoning over the manufacturer's own numbers plus one isolated measurement of a machine that is not in the group.
Westinghouse ePX3500 on Amazon Chemical Guys ProFlow PM2000 on Amazon Affiliate links. Amazon shows the live price; we do not copy prices onto this page because they go stale. See our disclosure.