Someone Is Living in My Rental Who Is Not on the Lease
An occupant who is not on the lease is a lease violation. Enforce it with paper, not a phone call. Check the guest clause and the occupancy clause. Then serve a 10-day notice under 735 ILCS 5/9-210. If the extra person stays past the 10 days, file an eviction. Name the tenant and "Unknown Occupants" so the order removes everyone in the unit. One caution first: in Chicago, a genuine sublet may be legal under the RLTO. My flat eviction fee is $1,600 in Chicago and $895 in DuPage, contested trial included.
You leased the unit to one person. Now the mail slot carries two names. A second car sits in the spot every night. The neighbor mentions "the boyfriend who moved in around Easter." Your instinct says stranger in my building, call someone. The law says something more useful. First decide what this person is. The label decides whether you have a case at all.
Is This Even a Lease Violation?
Three kinds of people can stand in that unit. Each one carries a different legal label. The label sets your next move.
A guest stays within the lease's guest limits and violates nothing.
A sublessee pays rent to the tenant under a real sublease arrangement.
An unauthorized occupant lives in the unit past the lease's limits with no sublease.
The guest. A well-drafted lease names every occupant. It also caps how many consecutive days a guest may stay. I put those clauses in every lease my office drafts. My guide to Chicago lease agreements explains why. A guest inside those limits has violated nothing. The sister who visits for two weeks is lawful. The partner who stays most weekends is lawful. Both annoy you, and both are invisible to a judge.
Do not serve a notice on a lawful guest. A dead notice teaches your tenant to ignore your notices.
The unauthorized occupant. The guest becomes an occupant when the stay outruns the lease's limits. Look for the signs of residence. The furniture moves in. The mail arrives. The person has no other residence. If your lease restricts occupancy to the named tenants, that conduct breaches a specific lease term. The 10-day notice path below is built for it.
The sublessee, and the Chicago fork. Chicago adds an honest complication. The Chicago RLTO gives tenants subletting rights: the landlord must accept a reasonable sublease, cannot unreasonably withhold consent, and cannot charge a sublet fee. My RLTO primer covers the ordinance's structure. Say your Chicago tenant took a six-month assignment in Texas. The tenant installed a paying sublessee. Nobody asked you first. The sublet still may not be a violation. An unreasonable refusal by you can become the tenant's claim against you. Outside Chicago, no such ordinance applies. In DuPage, Kane, and the rest of the collar counties, your lease's no-subletting clause means what it says. The line between a true sublessee and an unauthorized occupant turns on one question. Does a real sublease arrangement with the tenant exist? The line is blurry at the edges. That protection belongs to Chicago and suburban Cook County. In the collar counties, no such right exists, and your clause controls.
A genuine sublessee in Chicago is probably not a violation. The RLTO protects a reasonable sublease even when nobody asked you first. Review the sublease before you serve anything.
| Who is actually in the unit | Lease violation? | Your move |
|---|---|---|
| Guest within the lease's guest limits | ✗ No | Do nothing. Watch the calendar and keep notes. |
| Genuine sublessee in Chicago, tenant coming back | ✗ Probably not, under the RLTO | Review the sublease. An unreasonable refusal by you can create liability for you. |
| Occupant beyond the lease's limits, no real sublet | ✓ Yes | Serve the 10-day notice under 735 ILCS 5/9-210. File the eviction if the tenant does not cure. |
| Original tenant gone, only the stranger remains | Different case entirely | Serve a demand for possession. File an occupant-focused eviction. See the last section. |
Why Can't I Just Call the Police or Change the Locks?
Do not call the police for a trespass. The officer will tell you to go to court.
Do not change the locks. A lockout hands the tenant a claim against you.
Do not accept rent from the occupant. A payment can create a new tenancy.
The trespass call fails for a clear reason. Police remove trespassers. Police do not remove residents. Once a person moves belongings in, the responding officer sees a residence dispute, not an intrusion. Only one official in Illinois removes an occupant from a dwelling. That official is the sheriff, and the sheriff acts only on an eviction order. I hit the same wall with tenants who signed the lease under a fake identity. Felony-grade conduct on the application did not make the removal a police matter. An extra occupant is not a crime at all. The police will not touch it.
The lockout is worse than useless. Change the locks in Chicago and the tenant gains a claim under RLTO § 5-12-160. That is the lockout provision. It carries per-day fines and damages. Self-help against an occupied unit creates liability everywhere in Illinois. It creates liability fastest in the county where you are most likely to try it.
The third mistake is quieter: money from the new occupant. It feels like found revenue. Someone finally pays for the second body in the unit. Do not cash that check. Accepting rent from the occupant creates a tenancy with the occupant. That is the rule, hard stop. Then you run a second eviction against a person you made a tenant. Collect rent from the tenant named on the lease and nobody else.
What Is the Right Sequence?
Document the occupancy
Photograph the mail and the second vehicle. Photograph the moved-in furniture if you are in the unit lawfully for another reason. Save the neighbor's texts. Note the dates. These facts fill the factual paragraph in the notice. Eight weeks later, the same facts become testimony that survives cross-examination.
Check the lease and the RLTO
Find the occupancy clause and the guest clause. Confirm the person is outside both. In Chicago, rule out the sublet question from the section above before you serve anything.
Serve the 10-day notice
The notice under 735 ILCS 5/9-210 covers lease violations other than nonpayment. It carries a cure period. The tenant gets 10 days to fix the breach. Here, the fix is that the extra person moves out.
Be specific. Specificity separates notices that hold up from notices that get cases dismissed. "You are violating the lease" fails. "On April 12, 2026, unauthorized occupant John Doe was observed living in the unit in violation of Paragraph 7 of the lease" holds. My full guide to the 5-day, 10-day, and 30-day notices covers the drafting details.
Serve the notice correctly under 735 ILCS 5/9-211. Hand it to the tenant. Or leave it with a person age 13 or older who resides in the unit. The unauthorized occupant who answers the door counts. Or send it certified mail and wait for the signed receipt from the addressee. Regular mail is not a listed method. Tape on the door of an occupied unit is not posting service.
Expect the cure, and treat the cure as a win. Most of these cases end with the occupant gone by day nine. The tenancy survives. Your file now documents a breach. The tenant has learned your notices are real.
File, and name "Unknown Occupants"
The eviction follows the standard steps in my Illinois eviction process guide. Add one thing that matters more here than anywhere. Name the tenant and "Unknown Occupants" as defendants under 735 ILCS 5/9-107.5. The order then binds everyone the sheriff finds in the unit. It binds the person whose name you never learned.
Leave them out of the caption and section 9-107.5(b) sends you on a detour. The sheriff posts a notice at execution. The unknown occupant gets 7 days to petition the court for a hearing. You make another trip to the courthouse. I detailed that trap in the fake-identity article. The fix is identical: caption the case right the first time.
Filing runs $389.25 in Cook County. Filing fees of $300 to $389 are the client's cost in every county I practice in. The notice forms themselves are free in my eviction resources library.
"I run 150+ evictions a year. The extra-occupant case is a weekly event in my office, not a puzzle."
Flat-Fee Eviction: $1,600 Chicago, $895 DuPage, $995 Kane. Notice Through Trial.
Send me the lease and the tenant's name. Tell me who is actually living in the unit. On a free 30-minute call, I will tell you what you have. It is a lease violation, a lawful Chicago sublet, or a holdover occupant. I will tell you exactly what the notice should say. Suburban Cook runs $895 to $1,250 by district, contested trial included. Court filing fees of $300 to $389 are the only cost on top.
All consultations are confidential.
What If the Original Tenant Left and Only the Stranger Remains?
Sometimes the notice flushes out the real situation. Your tenant quietly moved to Indiana months ago. The tenant kept the lease as a shield. The person who answers the door is the only person living there. That is no longer a lease-violation case. The tenant you would serve has surrendered the unit. The case becomes an eviction against an occupant who has no lease with you at all. That case has its own playbook. A court affidavit replaces the lease at filing. Start with my guide to eviction without a lease in Illinois. If the occupant arrived with no connection to any tenant, read the squatter eviction guide next.
A word on SB 1563, the 2026 Illinois squatter law. On paper, it lets police remove intruders on a sworn affidavit. My firm's experience in Cook County is different. Police do not enforce it, even on qualifying facts. Plan around the eviction, not the affidavit. The Demand for Immediate Possession form for these cases is a free download in my eviction resources hub.
Frequently Asked Questions
Can I evict someone who is not on the lease in Illinois?
Yes. Serve your tenant a 10-day notice under 735 ILCS 5/9-210 for the breach of the occupancy clause. If the extra person stays past the 10 days, file the eviction. Name the tenant and "Unknown Occupants" as defendants under 735 ILCS 5/9-107.5. The order then covers everyone the sheriff finds in the unit, even a person you never name.
Can the police remove an unauthorized occupant?
Almost never. A person who moves belongings in has established residence. Police treat that dispute as a civil matter. Only the sheriff removes an occupant from a dwelling, and only under an eviction order. A trespass call ends with an officer who tells you to go to court. Skip the call. Start with the notice.
Is subletting without permission illegal in Chicago?
Often it is not even a lease violation. The Chicago RLTO gives tenants subletting rights: the landlord must accept a reasonable sublease, cannot unreasonably withhold consent, and cannot charge a sublet fee. A genuine sublessee in Chicago may be lawfully in the unit even though you never approved anyone. Outside Chicago, in DuPage, Kane, and the other collar counties, no such ordinance applies and the lease controls.
Should I accept rent from the person living there?
No. Wait until an attorney reviews the situation. A payment straight from the occupant can make the occupant your tenant. Then you must serve the occupant separate notices and prove a separate case against the occupant. Collect rent only from the tenant named on the lease. Document any payment the occupant offers, and do not cash the check.