The Complete Illinois Landlord Legal Guide for 2026
Illinois is unusual among large states because most residential landlord rules live in short, scattered statutes rather than one consolidated chapter. The state baseline is thin, but Cook County and the City of Chicago each layer their own ordinances on top, and those overlays are where most landlord mistakes happen. Our team mapped every Illinois statute a small residential landlord touches, and this guide pulls the core requirements into one place for 2026.
Nothing here is legal advice. It is a plain-English summary with full citations so you can verify anything yourself.
This guide is written for small Illinois landlords in three profiles. The owner of a single-family home, two-flat, three-flat, or six-flat in Chicago or the surrounding Cook County suburbs, renting out without a property management company. The downstate landlord with units in Springfield, Peoria, Rockford, Champaign, or Bloomington-Normal, where Chicago RLTO does not apply but state and federal rules still do. The accidental landlord who inherited a property, relocated, or chose to rent rather than sell.
If your unit sits inside the Chicago city limits, the Chicago Residential Landlord and Tenant Ordinance (RLTO) applies and is in many places stricter than state law. If your unit sits in unincorporated Cook County or in an opted-in Cook County municipality, the Cook County Residential Tenant Landlord Ordinance (RTLO) applies. Both overlays stack on state law. This guide covers the state baseline and flags where the local rules change the answer.
## Illinois Residential Landlord and Tenant Act overview
Illinois does not have a single comprehensive landlord-tenant code the way California or Florida do. The framework is a patchwork of separate acts:
- The Landlord and Tenant Act, 765 ILCS 705, which bans certain lease provisions and sets the rent withholding framework.
- The Security Deposit Return Act, 765 ILCS 710, governing return timing and itemization in larger buildings.
- The Security Deposit Interest Act, 765 ILCS 715, governing deposit interest in 25+ unit buildings.
- The Forcible Entry and Detainer Act, 735 ILCS 5/9-101 through 9-321, governing notices and the eviction lawsuit (Illinois practice now calls this the Eviction Act, still cited under Article IX of the Code of Civil Procedure).
- The Illinois Radon Awareness Act, 420 ILCS 46.
- The Retaliatory Eviction Act, 765 ILCS 720.
On top of that, the Cook County RTLO and Chicago RLTO add ordinance-level obligations including stricter deposit rules, broader required disclosures, late fee caps, and a private right of action with attorney fees.
Two structural points our team comes back to: Illinois state law is the floor, and Chicago RLTO and Cook County RTLO are both meaningfully stricter. And writing matters, because Illinois courts treat written notices strictly. A defective notice usually has to be reissued and reserved, restarting the clock.
## Security deposit rules (765 ILCS 710 and 715)
Illinois has two state-level security deposit statutes that apply at different building sizes, plus the Chicago RLTO and Cook County RTLO overlays.
State law: the 25-unit threshold
The Security Deposit Interest Act, 765 ILCS 715, requires landlords of buildings with 25 or more units to pay interest on deposits held more than six months. The interest rate is set annually based on the rate paid by the largest commercial bank in Illinois. For buildings under 25 units, no statewide interest obligation applies.
The Security Deposit Return Act, 765 ILCS 710, applies to landlords of 5 or more units. If the landlord intends to deduct for damage, the landlord must furnish the tenant with an itemized statement plus paid receipts or estimates within 30 days of the tenant vacating. If the landlord fails to do so, the landlord must return the full deposit within 45 days of the tenant vacating.
For buildings under 5 units, neither statute imposes a fixed itemization timeline, but case law requires return within a reasonable time. Our team treats 30 days as the practical floor everywhere in Illinois.
Chicago RLTO
Chicago's RLTO (Municipal Code Chapter 5-12) is stricter. Deposits in covered Chicago units must be held in a separate, federally insured, interest-bearing account in an Illinois financial institution, with annual interest paid to the tenant. The landlord must provide a written receipt identifying the depository. Deposits must be returned within 45 days of the tenant vacating, with itemized deductions delivered within 30 days. Penalties are unforgiving: failure to comply can entitle the tenant to two times the deposit plus attorney fees.
Cook County RTLO
The Cook County RTLO mirrors much of the Chicago framework for unincorporated Cook County and opted-in municipalities. Deposit interest, written receipt, and 30-day itemization timelines apply.
What we see go wrong
The most common deposit mistake we audit is treating the state Security Deposit Return Act as the only rule when the property is actually inside Chicago or Cook County. The state rule does not preempt the local rule, it sits underneath it. A Chicago landlord who returns a deposit on day 35 with no itemization is exposed to a two-times penalty plus fees.
## Notice to quit and termination rules
Illinois notice rules live in Article IX of the Code of Civil Procedure, 735 ILCS 5/9-101 et seq. There are four notice periods a small landlord needs to know cold.
5-day notice for non-payment of rent (735 ILCS 5/9-209). When a tenant fails to pay rent, the landlord may serve a written 5-day notice demanding payment. If the tenant pays the full amount within 5 days, the tenancy continues. The amount demanded must be rent only, not late fees, and the notice must state the exact rent amount.
10-day notice for material breach (735 ILCS 5/9-210). For lease violations other than non-payment, the landlord serves a 10-day notice. Illinois does not require a cure opportunity unless the lease provides one, but the breach must be material.
30-day notice to terminate a month-to-month tenancy (735 ILCS 5/9-207). Either party may terminate a month-to-month tenancy with 30 days written notice ending on the last day of a rental period. This applies regardless of how long the tenant has occupied the unit.
Year-to-year tenancies (735 ILCS 5/9-205). If a tenancy has rolled into a year-to-year arrangement (rare in practice; most Illinois tenants are on a fresh annual lease or month-to-month), 735 ILCS 5/9-205 sets the statutory notice at 60 days, served within the four months preceding the last 60 days of the lease year. The default rule for an ordinary month-to-month tenancy is the 30-day notice in 9-207, regardless of how long the tenant has occupied the unit.
No-cause termination during a fixed-term lease. Illinois does not give the landlord a no-cause exit during a fixed term. The lease ends on its own date.
A defective notice is the most common reason an Illinois eviction fails. Wrong amount, wrong date, demanding rent and late fees together, or counting weekends in the service window can each sink the case.
Illinois has no statewide rent control and no statewide cap on rent increases. The Rent Control Preemption Act, 50 ILCS 825, expressly bars Illinois municipalities from enacting rent control.
What the state requires is proper notice. For a month-to-month tenancy, a rent increase is a change in lease terms and must be served with the same 30 or 60 day notice that would terminate the tenancy. For a fixed-term lease, rent cannot be raised mid-term unless the lease reserves the right.
Chicago's RLTO requires written notice of rent increase, generally 30 days for tenancies under six months, 60 days for six months to three years, and 120 days for three years or longer (Municipal Code 5-12-130(j)). Cook County's RTLO requires similar advance notice. Most generic templates skip these advance notice requirements, which is one reason a generic US lease misfires inside Cook County.
HB 2562 (103rd General Assembly) would have added statewide notice content requirements for rent increases, but had not passed into law as of this guide's update date. Status uncertain, verify on the Illinois General Assembly site before relying on it.
## Radon disclosure (Illinois Radon Awareness Act, 420 ILCS 46)
Illinois is one of the few states with a statutory residential rental radon disclosure. The Illinois Radon Awareness Act, 420 ILCS 46, requires landlords to disclose any known radon hazards and to provide the IEMA (Illinois Emergency Management Agency) "Radon Guide for Tenants" pamphlet before the tenant signs the lease.
The disclosure has three parts: a written notice of any known radon hazard, including any radon test result above 4 pCi/L received by the landlord; the IEMA tenant pamphlet, current edition, attached to or delivered with the lease; and a signed acknowledgment by the tenant.
The landlord is not required to test for radon. The disclosure duty applies only to results the landlord actually has. But if the landlord has tested and the result is above the threshold, the landlord must disclose, and any future test result above the threshold must also be disclosed. The Act applies to dwelling units below the third story above ground.
Many off-the-shelf "Illinois lease" templates either omit the radon disclosure entirely or include language that does not match the current 420 ILCS 46 requirements. Our team treats the radon disclosure as one of the two highest-priority Illinois lease clauses, alongside the security deposit framework.
## Mandatory disclosures beyond radon
Illinois layers several other disclosure duties on radon, partly federal and partly local.
Lead-based paint (federal, 42 U.S.C. 4852d, 24 C.F.R. part 35 subpart A). Required for any rental built before 1978. Provide the EPA pamphlet "Protect Your Family From Lead in Your Home," sign the federal lead-based paint disclosure form, and offer a 10-day inspection opportunity.
Chicago heat and hot water (RLTO 5-12-110, 5-12-160). Chicago's heat ordinance requires minimum indoor temperatures of 68 degrees during daytime and 66 at night during the heat season (September 15 through June 1). Failure to maintain heat is one of the most actionable RLTO violations.
Cook County source of income protection. The Cook County Human Rights Ordinance prohibits source-of-income discrimination, including refusal to rent to Housing Choice Voucher (Section 8) holders, and bars screening practices that filter out voucher holders.
Cook County sealed records (Just Housing Amendment). The Just Housing Amendment restricts how landlords use criminal background information in screening, including sealed and expunged records.
Known defects and mold. Illinois has no statewide Mello-style disclosure or mold statute. Both run through the implied warranty of habitability. Failure to disclose a known dangerous condition can ground a tort claim.
Illinois has no statewide statutory cap on residential late fees. Late fees are governed by ordinary contract principles. A fee that bears no reasonable relationship to actual damages from late payment can be struck down as a penalty.
Cook County RTLO cap. Late fees in Cook County covered units are capped at $10 per month for the first $1,000 of rent plus 5 percent per month on any rent above $1,000. Anything beyond that is unenforceable under the ordinance.
Chicago RLTO. Chicago RLTO 5-12-140(h) caps late fees at $10 per month for rent under $500 and $10 plus 5 percent per month of any amount over $500.
Outside Cook County. Downstate Illinois has no ordinance cap, only the case-law reasonableness test. Our team's drafting default for Illinois leases outside Cook County is 5 percent of monthly rent after a 5-day grace period.
A late fee cannot be collected through a 5-day notice for non-payment under 735 ILCS 5/9-209. The 5-day notice may demand only rent. Late fees must be pursued separately or as part of a damages claim.
Illinois recognizes an implied warranty of habitability in residential leases, established in Jack Spring, Inc. v. Little, 50 Ill. 2d 351 (1972). The landlord must maintain the unit fit for human habitation, read alongside applicable building, housing, and health codes.
Heat and Hot Water Act (765 ILCS 715/2). A landlord who agrees to provide heat or hot water cannot fail to provide them in adequate quantities. Breach can support a habitability defense in eviction or termination by the tenant.
Rent withholding (765 ILCS 705/1.2). Illinois allows limited rent withholding when the landlord fails to maintain the premises and the tenant follows a strict notice and escrow procedure. The practical takeaway: any written tenant complaint about habitability should be answered in writing and addressed promptly.
Retaliatory Eviction Act (765 ILCS 720). A landlord may not terminate or refuse to renew in retaliation for a tenant complaint to a code enforcement body.
Chicago RLTO 5-12-110 maintenance duty. Chicago overlays a more detailed repair obligation, with statutory remedies including rent abatement, repair-and-deduct, and termination after notice.
Illinois eviction is governed by the Forcible Entry and Detainer Act, 735 ILCS 5/9-101 through 9-321 (Illinois practice now calls this the Eviction Act).
Step 1: serve the proper notice. 5 days for non-payment under 735 ILCS 5/9-209, 10 days for material breach under 735 ILCS 5/9-210, 30 days for month-to-month termination under 735 ILCS 5/9-207 (or 60 days for a year-to-year tenancy under 735 ILCS 5/9-205).
Step 2: file the eviction complaint. After the notice period expires without cure or vacancy, the landlord files in the circuit court of the county where the property is located. In Cook County the case goes to the First Municipal District eviction call.
Step 3: summons and trial. Illinois eviction is a summary proceeding. Uncontested cases in Cook County resolve in two to six weeks; contested cases run longer. Downstate counties tend to move faster than Cook.
Step 4: judgment and possession. If the court rules for the landlord, judgment enters and the tenant has a stay period before the sheriff enforces the order. Self-help is unlawful: changing locks or removing belongings without a sheriff exposes the landlord to liability.
Step 5: appeal window. Either side has 30 days to appeal. A tenant who appeals must usually post a bond.
The Chicago RLTO does not have its own eviction process, but it adds defenses and counterclaims that can be raised inside the state action.
Three mistakes appear repeatedly in the Illinois leases our team audits.
Missing the radon disclosure. Generic US lease templates do not include 420 ILCS 46 disclosure language. Landlords who use a generic template often discover at year end that they have been technically non-compliant since day one. Including the disclosure paragraph and the IEMA pamphlet at signing closes this risk.
Wrong notice periods. Landlords serve a 5-day notice and include late fees in the demand, making the notice defective. They confuse the 30-day month-to-month rule (735 ILCS 5/9-207) with the 60-day year-to-year rule (735 ILCS 5/9-205) and serve the wrong period for the actual tenancy type. Each error restarts the clock.
Chicago RLTO non-compliance. A landlord using a generic Illinois template inside the City of Chicago is almost always non-compliant on one or more RLTO sections: deposit interest, the RLTO summary attachment (5-12-170), heat ordinance, or the late fee cap. Each non-compliance is independently actionable.
## When to consult an attorney
This guide and a well-drafted Illinois lease can carry a small landlord through a clean tenancy. Our team would tell you to pay for an hour of an Illinois licensed attorney's time in three situations.
First, any contested eviction inside Chicago or Cook County involving an RLTO or RTLO defense. The local ordinances add procedural and substantive defenses that experienced tenant attorneys will raise. Going pro se against a tenant with counsel is a hard road.
Second, lead-based paint claims. Federal lead disclosure violations are statutory damages cases with attorney fees, and a missed disclosure can produce a material claim even without proven harm.
Third, repair-and-deduct or rent withholding disputes where the tenant has gone through the 765 ILCS 705/1.2 procedure or the Chicago RLTO equivalents. These are technical statutes and small procedural errors swing the outcome. A landlord who has received a properly noticed tenant withholding letter should not respond without counsel.
How long do I have to return the security deposit in Illinois? Under 765 ILCS 710 (5 or more units), the landlord must furnish an itemized statement within 30 days of the tenant vacating and return any remaining balance within 45 days. Smaller buildings have no fixed state deadline, but our team treats 30 days as the practical floor. In Chicago and Cook County the local ordinance imposes 30 day itemization with full return at 45 days and a two times penalty for non-compliance.
Do I have to pay interest on the security deposit? At the state level, only if the building has 25 or more units (765 ILCS 715). In Chicago and in Cook County RTLO covered units, yes regardless of building size.
How much notice do I need to give to terminate a month-to-month tenancy? 30 days under 735 ILCS 5/9-207 for a month-to-month tenancy. The 60-day notice under 735 ILCS 5/9-205 only applies if the tenancy has rolled into a year-to-year arrangement, which is rare in practice.
Is my Illinois rental subject to rent control? No. The Rent Control Preemption Act, 50 ILCS 825, bars Illinois municipalities from enacting rent control. There is no statewide cap on increases, but you must serve the proper termination notice when changing rent on a month-to-month tenant.
Do I need to disclose radon? Yes, if you have any test result above 4 pCi/L, and you must provide the IEMA tenant pamphlet before lease signing for units below the third story. You are not required to test, but if you have, you must disclose (420 ILCS 46).
Can I charge whatever late fee I want? Outside Cook County, the limit is the case-law reasonableness test. Cook County RTLO caps fees at $10 per month for the first $1,000 of rent plus 5 percent on any amount above $1,000. Chicago RLTO 5-12-140(h) caps fees at $10 per month for rent under $500 and $10 plus 5 percent for rent over $500.
Can I evict a tenant in 5 days? No. The 5 day notice under 735 ILCS 5/9-209 starts the process. After it expires without payment, you file the eviction case, which takes weeks. In Cook County, two to six weeks is typical uncontested. Self-help lockouts are unlawful.
If you need an Illinois residential lease that includes the radon disclosure, IL Heat Hot Water Act language, and Cook County / Chicago compliance, our team's Illinois lease template at leasekit.io/templates/illinois-residential-lease covers it for $29 one-time.