The rules are a little different if the adult occupants are unrelated (roommates).

They're oddly kind of like having a roommate, where if they were in a large apartment complex, they wouldn't have the same type of relationship - it would be more anonymous.Why were they both needing a garbage can? 

Roommates? 

(Certain terms are void, such as not allowing pets and not allowing roommates.)Thanks in advance!

I would (1) write a letter to the current tenant stating that rent will go up $50 per month as there is an unauthorized roommate residing in the home. 

You can read alot of books and listen to a bankers opinion all day but what help are they going to be when you enter a unit for a filter change and smoke alarm battery check and you discover things like tenant has moved in a roommate, are those bedbugs on the wall, why is there a pet tiger in the bedroom...etc...You will need a voice to call to say what in the hell do I do?

For anyone who has rented a property by the room as opposed to an entire unit or house, or has rented out one room to roommate via a rent-by-the-room house hack, are there any special considerations for doing so in Chicago?

@Bruce ParkA house hack is basically just a roommate situation.

In this environment, when courts do open up, they may be very considerate of a tenant who left because they were being forced to allow new roommates with no way to know if they are a health risk, so I wouldn't count on more than the security deposit.  

If you pick the right roommates it’s also relatively passive and you get built-in friends.