Avoid any so-called "contractors" that knock on your door, tell you they're working in the neighborhood, and ask if you need assistance.
Make sure you get information about any contractor you hire: his name, business name, business address, phone numbers, and references. Look at the vehicle the contractor drives . . . is the business name / address / phone number on the truck? Take a few minutes to check out the contractor on the internet or with the BBB.
DO ask for a copy of the contractor's City of Chicago business license and current certificate of insurance. Make sure the documents you see are up-to-date. Check for a company's business license on the city's website.
Roofers working in Chicago must have 2 licenses: a home repair license and a limited business license.
If your roof is leaking, don't assume you need a brand new roof. Get at least 2 or 3 estimates before you hire a contractor to install a new roof. Leaks may be simply repaired by re-sealing openings.
Plumbers working in Chicago to rod out drains need a Sewer License, issued by the Department of Water Management. Ask to see the current license.
Ask if water backup in your home may be due to blockage in the street that the City will repair. Call 311 if your plumber suspects sewer line blockage not on your private property.
DO make sure that any contract you sign details all of the repairs that you discuss with the contractor. DON'T assume the contractor will do what you want unless you have it in writing.]
DON'T make the final payment unless you are satisfied with the work. If it's dark when the work is completed, tell the contractor to come back in the morning so that you can see the repairs when it's light to make sure the work is ok.
DO be wary of companies advertising flood clean-up services. Make sure you understand all potential charges before you agree to the services. For example, how will you be charged for fans brought into your home to dry out the carpet, by the man-hour or per fan? What if fans are left overnight? How will you be charged for removal of water, by the time it takes to remove the water or by the amount of water removed?