I want to take on pressure washing during the "off season" and then incorporate it into the business full time at the start of next year. My question is what would be a good washer to purchase? What would be the minimum psi I should consider when shopping for one? Most of the work will be mainly driveways, sidewalks and pool decks and patios. I have been approached about doing houses as well (siding). I just want to be safe and not buy something too small or underpowered, but don't know what brand or size to get. Any advice would be much appreciated! Thank you!