Updated: Aug 6, 2021
One of the main differentiating factors of soft wash and pressure wash is one (Pressure) using high pressure and one (Soft) using a lower pressure. Pressure washing or power washing uses high-pressure water that runs at a very high PSI. Depending on the type and strength of pressure washer, the PSI can range from 1300 to 3100 PSI or Above. Meanwhile, soft washing uses much less power than that — more like a strong powered hose.
Another difference is what comes out of the hose with soft washing vs pressure washing. While a pressure wash relies on the high-pressure water alone to clean properly, soft washing systems use a combination of soaps, bleach, and water to ensure your exterior stays clean for the long-term.
For delicate surfaces like Vinyl, Aluminum, or Stucco, as well as Roofs need a soft wash, low pressure will avoid damages on siding or windows, fascia boars, trimming and other surfaces because the solution does the hard work and low pressure will only rinse off what the solution already removed from the surface.
pressure can only be used on hard surfaces like brick, concrete, stones, etc, that means pressure will do great for patios, driveways, and other none delicate areas, but won't be the best option for your house walls.