For your convenience, the Building Department is open Monday through Friday, 7:00 a.m. – 4:30 p.m. We will be happy to serve you in-person at 600 Main St. NW, by calling 815-937-3575 or via email: This email address is being protected from spambots. You need JavaScript enabled to view it.. After hours, you may leave a message and a representative will get back with you during normal business hours.