People have
water faucets and electrical outlets on the side of their houses. Sometimes they even have
hot water faucets out there. How about a pressure washer hose fitting? Put the pressure washer where it won't freeze in a utility room or laundry room. It's permanently hooked up and plumbed. When you want to use it outside to clean something, attach your pressure washer hose and wand to it at the side of the house. Either turn it on in the utility room at that point or invent a fitting that engages the pressure washer when the wand is attached to the fitting.
Now you can pressure wash all your stuff, even in the winter, without having to drag out the pressure washer.
If you get rich from this idea, please send me some money as a thank you :)