Illinois Security Deposit Laws & Demand Letter

The Illinois security deposit deadline

Under 765 ILCS 710/1 et seq., a Illinois landlord has two options after a tenant vacates the rental:

1. Return the full deposit within 30 days if no deductions are being claimed; or
2. Send a written notice of intent to impose a claim within 30 days, identifying the amount and reasons for any deductions.

If the landlord misses both windows, they generally forfeit any right to deductions and owe the tenant the full deposit. The relevant statutory language reads:

Sec. 1. (a) A lessor of residential real property, containing 5 or more units, who has received a security deposit from a lessee to secure the payment of rent or to compensate for damage to the leased premises may not withhold any part of that deposit as compensation for property damage unless he has, within 30 days of the date that the lessee vacated the premises, furnished to the lessee, delivered in person or by mail directed to his last known address, an itemized statement of the damage allegedly caused to the premises and the estimated or actual cost for repairing or replacing each item on that statement, attaching the paid receipts, or copies thereof, for the repair or replacement. ... If the lessor fails to comply with this Section, the lessor shall, upon a finding by a circuit court that he has refused to supply the itemized statement required by Section 1, or has supplied such statement in bad faith, and has failed or refused to return the amount of the security deposit due within the time limits provided, be liable for an amount equal to twice the amount of the security deposit due, together with court costs and reasonable attorney's fees.

Source: 765 ILCS 710/1 et seq.

Damages and remedies

Under Illinois' Security Deposit Return Act (765 ILCS 710), applicable to residential buildings of five or more units, a landlord who fails to comply with the 30-day itemization-or-refund requirement is liable for damages equal to twice the security deposit plus court costs and reasonable attorney's fees. The Act applies only to buildings of five or more units; smaller-building tenants must look to common law and any applicable city ordinance (e.g., Chicago RLTO).

Attorney's fees: Illinois law provides that the prevailing party in a deposit dispute is entitled to recover reasonable attorney's fees and court costs. This is a meaningful pressure point in your demand letter.

What to do next

1. Confirm your deadline. Use the calculator above with your move-out date.
2. Send a certified demand letter. A formal, statute-cited demand sent via USPS Certified Mail creates a documented record and is what most landlords respond to.
3. Wait 7-14 days. If no response, send a follow-up notice escalating the demand.
4. Consider small-claims court. Illinois small-claims court handles disputes up to $10,000. A clean case packet (lease, photos, certified-mail receipts, statute citation) is what wins these.

Common questions