1 pump or 2

Want to start soft wash/concrete washing business.
Will one pump (4+gpm) do the soft wash for homes and pressure washing for concrete?
Do I need a 2 pumps, 1 for soft washing and 1 for concrete pressure washing?

I think you need to read some more.

If you are talking about soft washing, that is normally done with a 12v or AR system, whereas cleaning concrete is normally done using a pressure washer which is used for down streaming. There are lots of ways to skin a cat, but that is some basic stuff. Cleaning concrete usually requires a larger machine if you are doing large areas. For a homeowner’s sidewalk or small drive a 4gpm unit would be enough. If you get into large, especially commercial concrete, you would want a larger unit (8 gpm) and maybe heat as well. A larger unit will let you run a bigger surface cleaner which will get the job done faster.

Peruse the forum, it is free and filled with gold.