Illinois Residential Lease Agreement

Radon disclosure & tenant testing rights (2024)

For leases entered into since Jan 1, 2024, landlords must give prospective tenants the IEMA pamphlet "Radon Guide for Tenants," copies of any records showing a radon hazard in the unit, and the statutory Disclosure of Information on Radon Hazards to Tenants form. The tenant then has 90 days to run their own radon test — and may terminate the lease if it shows a hazard the landlord declines to mitigate. Units on the 3rd story or higher are excluded.

Source: 420 ILCS 46/26 (P.A. 103-298)

"Concession Granted" legend on the lease

A 1925 law still in force: if the landlord gives any rent concession not stated in the lease (free months, rebates, anything of value), the lease itself must be stamped "Concession Granted" across its face in letters at least half an inch high, with a margin note describing the concession. Violations are a Class A misdemeanor.

Source: 765 ILCS 730/3

Shared utility formula (master meters)

A landlord may not bill tenants a share of master-metered utilities without first giving the tenant, in the lease or a separate writing, the formula used to split the bill — which must cover all users and may not total more than the utility actually charges. Tenants can demand copies of the underlying utility bills.

Source: 765 ILCS 740/5

Security deposit interest (25+ units)

Buildings or complexes with 25 or more units must pay interest on deposits held over 6 months, at the passbook rate of the largest Illinois bank, settled within 30 days after each 12-month rental period once accrued interest reaches $5. Willful failure costs the landlord an amount equal to the deposit plus fees.

Source: 765 ILCS 715/1-2

Lead-based paint (federal, pre-1978 buildings)

For housing built before 1978: disclose known lead-based paint hazards, provide the EPA pamphlet "Protect Your Family From Lead in Your Home," and include the federal lead warning language. Chicago and Cook County ordinances add further local requirements — check your municipality.

Source: 42 U.S.C. §4852d

How much security deposit can a landlord charge in Illinois?

Illinois does not set a statutory cap on the security deposit, so the amount is negotiable — but it must be returned within 45 days after you move out (as of 2026). Source: 765 ILCS 710 (Security Deposit Return Act).

Is this lease valid in Illinois?

A written lease that identifies the parties, the property, the term, and the rent is generally enforceable in Illinois once both sides sign. What it cannot do is contract around Illinois law: the deposit rules, entry notice, and habitability duties below apply whether or not the lease mentions them.

Can a tenant repair and deduct rent in Illinois?

Yes: if repair cost does not exceed the lesser of $500 or one-half monthly rent, tenant may notify landlord by certified/registered mail; if not repaired within 14 days (sooner in emergency) tenant may repair and deduct the paid bill from rent. Source: 765 ILCS 742/5 (Residential Tenants' Right to Repair Act, P.A. 93-891, eff. 1-1-05).

What does a landlord have to disclose in Illinois?

Under Illinois law: Radon disclosure & tenant testing rights (2024) (420 ILCS 46/26 (P.A. 103-298)); "Concession Granted" legend on the lease (765 ILCS 730/3); Shared utility formula (master meters) (765 ILCS 740/5); Security deposit interest (25+ units) (765 ILCS 715/1-2); Lead-based paint (federal, pre-1978 buildings) (42 U.S.C. §4852d). Federal and local rules can add more; each item on this page links to the law it comes from.