I just inspected a condo in that area today. I would recommend a through condo inspection of the roof, drainage, sump system, and foundation to make sure there is no seepage. Its a good idea to hire a home inspector who will look not only at your unit envelope, but is willing to inspect any systems that will effect your unit.
Gravity plays a role in the garden units.
Approximately how many units are in the building?
Have a look here for more information on Chicago Area Condo Inspections: http://www.home-inspection-chicago.com/Condo-Inspector-Chicago.html