Austin,
The advice above is partially true. DO worry about the chemicals. Using the proper chemicals is going to allow you to do a better job with less effort.
Tony is right though, that pressure washer does not have a high enough output to be very productive. It's not the PSI.......it's the GPM's.
Learn your chemicals, build your business, and invest in new equipment as soon as you can. Leasing is an option also, if you have good credit. Once you upgrade to a unit that is around 5 GPM's, you will never know how you cleaned anything without it!
Good luck........keep reading, and post anything that comes to mind.