Illinois Lease Agreement Requirements: What Landlords Must Include
An Illinois lease agreement is more than a rent figure and two signatures. State law and local ordinances impose duties on landlords around security deposits and disclosures, and a lease that ignores them can leave a landlord exposed. If you rent out property in Illinois, you want a lease that reflects both the statewide rules and any city ordinance that applies to your building.
Security deposit laws in Illinois
Illinois addresses security deposits through more than one statute, and the rules can turn on how many units a property contains. The Security Deposit Return Act, 765 ILCS 710, sets requirements around returning deposits and providing itemized statements of any deductions. The Security Deposit Interest Act, 765 ILCS 715, requires interest on deposits for larger buildings.
Under the Interest Act, a lessor of residential property containing 25 or more units in a single building or a complex of buildings on contiguous parcels must pay interest on a security deposit held for more than six months. The rate is tied to the passbook savings rate of the largest commercial bank in the state as of the December 31 before the lease begins. If you operate a smaller building, the Interest Act may not apply to you, but you should still confirm which rules cover your property before you draft deposit language.
The Return Act addresses the back end of the deposit, namely returning it and accounting for any deductions when a tenant moves out. If you withhold any portion of a deposit for damage, you generally need to give the tenant an itemized statement of what you kept and why, within the time the statute sets. Because the exact obligations and timelines can depend on the property, confirm the current text of 765 ILCS 710 before you write your return policy into the lease. The goal is a deposit clause that matches the law rather than a generic one copied from another state.
Required disclosures: radon and lead
Disclosures are a common gap in homemade leases. Illinois has a radon disclosure law that requires landlords to share known radon hazard information with tenants, and federal law requires a lead-based paint disclosure for most housing built before 1978. The lead rule applies nationwide, so an Illinois landlord renting an older unit must provide the federal disclosure and the accompanying pamphlet.
Build these disclosures into your lease packet rather than treating them as afterthoughts. Attach the lead-based paint disclosure form and the radon information where required, and keep signed copies. A structured lease helps make sure these forms travel with the agreement. You can start an Illinois residential lease at /lease-agreement/illinois/residential-lease.
Disclosures protect the landlord as much as the tenant. When you provide the required forms and keep a signed acknowledgment, you create a record that you met your legal duty, which matters if a dispute ever arises about what the tenant was told. Skipping a disclosure to save time is a false economy, because the missing form is exactly the document a tenant or a court will ask for later. Treat the disclosure packet as a standard part of every lease signing.
Chicago adds stricter rules
State law sets a floor, not a ceiling. The Chicago Residential Landlord and Tenant Ordinance, often called the CRLTO, imposes rules that are stricter than the statewide baseline for covered units inside the city. It addresses security deposit handling, interest, disclosures, and notices in detail, and it carries penalties for landlords who get the deposit rules wrong.
If your property sits within Chicago, you cannot rely on a generic Illinois lease alone. You need to confirm whether the CRLTO covers your unit and then follow its specific requirements, which can exceed what state law demands. Other Illinois municipalities, such as Evanston and Cook County more broadly, have their own ordinances as well, so check local rules wherever your property is located.
Local ordinances matter because they often attach their own notices and penalties. A Chicago landlord who mishandles a deposit, for example, can face consequences spelled out in the ordinance that go beyond the state statute. The practical lesson is to identify every layer of law that touches your unit before you draft, starting with the state statutes and then adding any city or county rule. A lease that satisfies state law but ignores a local ordinance can still land you in trouble.
Core terms every Illinois lease should state
Beyond deposits and disclosures, an Illinois lease should cover the basics clearly. Identify the parties and the property, state the rent amount and due date, and set the lease term. Spell out late fees, the security deposit amount and handling, maintenance responsibilities, and the rules for entry and notice. Clear, written terms reduce disputes and make the lease easier to enforce.
It also helps to describe the condition of the unit at move-in and to keep a signed copy for both sides. When the terms are written plainly, a tenant knows what is expected and a landlord has a record to point to if a disagreement arises.
Avoid clauses that try to waive a tenant's legal rights, because Illinois courts and local ordinances will not enforce a lease term that conflicts with the law. A clause that pretends to skip a required disclosure or strip a deposit protection does not help you and can undermine the rest of the lease. Write terms that work within the statutes and ordinances rather than against them, and your lease will be both fairer and more enforceable.
Putting an Illinois lease together
To assemble a lease that holds up, start with the statewide deposit rules and confirm whether the Interest Act applies based on your building size. Add the radon and lead disclosures your property requires. Check whether the CRLTO or another local ordinance covers your unit and follow its stricter terms. Then write the core lease terms clearly and keep signed copies of everything.
Because the rules vary by building size and city, confirm the specifics for your property rather than assuming one template fits all of Illinois. When you are ready to draft, you can build a lease at /lease-agreement/.
Sources
Frequently Asked Questions
Does an Illinois landlord have to pay interest on a security deposit?
Under the Security Deposit Interest Act, 765 ILCS 715, a lessor of residential property with 25 or more units must pay interest on a deposit held more than six months. Smaller buildings may fall outside that requirement, so confirm your building size.
What disclosures must an Illinois lease include?
Illinois landlords must share known radon hazard information under state law, and federal law requires a lead-based paint disclosure for most housing built before 1978. Attach the required forms and keep signed copies.
Do Chicago rentals follow different rules than the rest of Illinois?
Yes. The Chicago Residential Landlord and Tenant Ordinance imposes stricter rules than state law for covered units, including detailed deposit and disclosure requirements. Confirm whether the ordinance covers your unit and follow its terms.
Jill Stradley covers landlord-tenant law, lease agreements, and the fine print that renters and landlords skip until something goes wrong. Her goal is to make state-specific rental law readable for people who aren't lawyers and don't want to become one. She lives in a rental herself and considers that a professional asset.
View all posts →Create Your Lease Agreement
Need a lease agreement? Create one now for $7.99 - state-specific and professionally formatted.
Get Started - $7.99