The rule in Illinois
Illinois sets no statutory cap on the size of a residential security deposit: the source checked (Illinois General Assembly, 765 ILCS 710/1 (Security Deposit Return Act)) states no maximum, so the amount is whatever the lease says.
The return deadline is 45 days, counted after the tenant moves out (the full deposit, when no itemized statement was sent within 30 days). The text reads: “the lessor shall return the security deposit in full within 45 days of the date that the lessee vacated the premises.”
Of the 44 jurisdictions verified here, 36 give landlords less time and 3 give more; the median is 30 days. Indiana, Maryland, Oklahoma and Virginia also allow 45 days.
Without a cap there is no dollar ceiling to compute. For comparison, 27 of the 44 verified jurisdictions do cap deposits, from one month's rent in states such as Alabama up to three months' rent in Nevada.
Worked date: if the clock starts on November 30, 2026, the deadline falls on January 14, 2027. The separate 30-day notice of a claim would be due by December 30, 2026.
In neighbouring states with verified rules: Indiana allows 45 days and sets no cap, Iowa allows 30 days and caps deposits at two months' rent, Missouri allows 30 days and caps deposits at two months' rent and Wisconsin allows 21 days and sets no cap.
To keep any part of the deposit for damage, the landlord must send an itemized statement within 30 days of the date the tenant vacated or the tenant's right of possession ended, whichever is later.
The Act sets no maximum amount.
If a deposit is not returned, the small claims limit in Illinois is $10,000 (small claims rules).
Source: Illinois General Assembly, 765 ILCS 710/1 (Security Deposit Return Act) · last checked October 21, 2026.
If the deposit does not come back
The statute above sets the deadline; what happens after it passes is covered in general terms in the guide on a deposit that is not returned, and the way each state starts and counts the clock is compared in how deposit deadlines are counted.
Questions
How much can a landlord charge as a security deposit in Illinois?
Illinois law sets no maximum in the source checked (765 ILCS 710/1); the lease sets the amount.
How long does a landlord in Illinois have to return a deposit?
45 days: “the lessor shall return the security deposit in full within 45 days of the date that the lessee vacated the premises” (765 ILCS 710/1).
When does the Illinois deadline start?
The clock runs after the tenant moves out (the full deposit, when no itemized statement was sent within 30 days).