Hi Pacts,
If your going to start slow, you could purchase your machine from Home Depot.
It should get you through a year or so. I recommend that you skip that purchase and buy a quality commercial machine,
It will cost you more, but will last you a heck of a lot longer. Which means that it really is smarter and cheaper to get a good machine.
If your mainly doing residential stuff, you wont need a lot of pressure. The proper chemical selection will do the work for you.
I highly recommend a machine with as much water volume as possible. 4 to 5 gallons per min. It will help speed up your rinse time.
As for insurance, you will need to protect yourself as well as any potential customers. You should at least get liability insurance. One million in coverage is average.
You should contact insurance companies in your area, and ask them questions. Also you should protect you equipment with a umbrella and or marine policy.
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Dan Flynn
Flynn Service Pro
www.powerwash.net
708 715-4205