According to IL State Law, your landlord must pay you interest on your security deposit if it is held for longer than 6 months and there are 25 units or more in your building/complex. Your landlord has the choice of either applying this as a credit to your rent or paying you directly. You may sue your landlord should he/she fail to provide interests back on your security deposit (if you meet the criteria above) for the security deposit, interest, court costs and attorney's fees.
The Illinois Security Deposit Return Act stipulates the following:
Your landlord MUST return your security deposit in full within 45 days from the date you moved if your building consists of five or more units and you have satisfied all of the following requirements:
- You do not owe any back rent.
- You have not damaged the rental unit in any way beyond reasonable wear and tear.
- You have cleaned the apartment before you moved out.