Who should be on the lease in Chicago (and who decides)
Who must sign a Chicago lease, who pays when a roommate doesn't, how many can live there, and whether the landlord, City, Illinois or federal law decides.
Amin · Founder of Xzerno · former Chicago leasing agent
Published · Updated · 13 min readPublished · Last updated · 13 min read
No Chicago or Illinois law says every adult in an apartment has to be on the lease. Your landlord decides that, along with how each roommate is screened and how guests are handled, and the City, Illinois and federal law set the limits around those choices. Who's on the lease matters most on the day someone stops paying, because on one shared lease, any of you can be held to the whole rent. Below, each question roommates ask, who rules it, and a checklist to save. Everything here was read on Oct 16, 2026.
Who should be on the lease?
Who decides: the landlord, inside City and State limits.
Chicago's Residential Landlord and Tenant Ordinance (RLTO) doesn't define a tenant by a signature. A tenant is someone entitled to live in the unit by a written or spoken agreement, by a subtenancy the landlord approved, or "by sufferance" (RLTO §5-12-030(j)). Illinois Legal Aid Online adds that a spoken agreement letting an adult move in can create a lease, spoken leases of up to one year are allowed, and a person who can't show a legal right to live there can be removed (Illinois Legal Aid Online, spoken and written leases).
So the paper isn't the whole story, but it's the clearest proof you have. Here's who rules each question in this guide:
| The question | Who decides | What we found |
|---|---|---|
| Must every adult be on the lease? | Landlord | No Chicago or Illinois law requires it |
| Does each roommate have to qualify? | Landlord, within State law | Landlord sets the criteria, the same ones for every applicant |
| How long can a guest stay? | Landlord, through the lease | No law sets a number of days |
| Who pays if one roommate doesn't? | The lease you sign, then eviction law | On one joint lease, each of you can be held to the whole rent |
| Can you sublet a room? | City (RLTO) and your lease | Clear when a tenant leaves early; unsettled when the tenant stays |
| Can you add or swap a roommate mid-lease? | Landlord; State fee rules from 2027 | No law gives you the right; some fees banned from Jan 1, 2027 |
| How many people can live there? | City, with a federal guideline | Floor-area minimums, a zoning "household", a two-per-bedroom guideline |
| What can't a landlord hold against you? | City, State and federal law | Any protected trait, and the three lists differ |
Who rules each roommate lease question in Chicago, as read Oct 16, 2026. "Who decides" is our summary of the sources at the end of this page.
Does everyone living there have to be on the lease?
Who decides: the landlord.
We found no Chicago or Illinois law that requires every adult in a unit to be on the lease, or each one to pass screening. Both are landlord policy, so ask yours. A landlord who screens can weigh credit, rental history and employment, and must use the same criteria for every applicant (Illinois Legal Aid Online, revised Mar 25, 2026).
The law sorts the people in an apartment into three groups:
- A tenant has an agreement with the landlord, written or spoken (RLTO §5-12-030).
- A subtenant rents from a tenant and pays rent to that tenant, not to the landlord.
- An occupant lives there but isn't on the lease and isn't renting from anyone on it.
Guests are the landlord's call too. A private landlord can limit them if the limit is in the lease and reasonable; Illinois Legal Aid Online's examples are one overnight guest at a time, two overnights a week, or a two-week cap on a stay (revised Feb 15, 2026). No Chicago or Illinois law sets how many days turn a guest into an occupant, so your lease's guest clause is the answer. Read it before a partner starts staying over most nights.
What happens if one roommate stops paying?
Who decides: the lease you signed, then State and City eviction rules.
Illinois Legal Aid Online lays out three cases (Illinois Legal Aid Online, dealing with unpaid rent, revised May 5, 2026):
- One joint lease. The landlord can serve the unpaid-rent notice on everyone, even if only one roommate missed their share. Each of you is responsible for bringing the whole account current, and the landlord can bring one eviction case against all of you.
- Separate leases for each room. The notice and the case go only against the person who didn't pay.
- A tenant with subtenants. The landlord can serve the notice on the tenant and everyone living there, whether or not the subtenants paid. A tenant who wants a subtenant out has to go through the same written notice and eviction process a landlord would.
In buildings the RLTO covers, a landlord can end the lease if rent is still unpaid 5 days after a written notice, and the tenant has a one-time right to cure, meaning to pay what's owed, before an eviction order (RLTO §5-12-130(a)). The RLTO doesn't cover owner-occupied buildings with six or fewer units, or dorms and university housing (§5-12-020).
It can follow you. Tenant screening reports can include eviction actions and lawsuits, according to the federal Consumer Financial Protection Bureau, and on a joint lease that case names everyone. We found nothing showing a roommate's unpaid share lands on your credit report by itself, so the honest word is "can", not "will".
If someone leaves early from an RLTO building, the landlord has to make a good-faith effort to re-rent at a fair rent. If that fails, the tenant owes rent for the rest of the term plus advertising costs; if it works, they owe the difference (RLTO §5-12-120). Who stays liable is a lease question, and the Illinois State Bar Association's guide says a tenant stays responsible after a sublease or assignment unless the landlord releases them. We found nothing in the RLTO on what happens to a deposit when one co-tenant leaves, so check your lease; deposit basics are in our guide to finding a roommate in Chicago.
Should my roommate be on the lease?
Who decides: you choose what to ask for, and the landlord decides what to offer.
| Setup | Good for | The cost or the risk |
|---|---|---|
| Everyone on one lease | Equal standing with the landlord; nobody treated as a guest | Each of you can be held to the full rent and named in one eviction case |
| Separate leases per room | Nobody is liable for someone else's share | Only if the landlord offers it; we found no data on how common it is |
| One lead tenant, subtenants | The lead tenant controls who moves in | The lead tenant stays liable for all the rent and may take on landlord duties |
| A roommate not on the lease | Easy to start | Unclear standing, a possible lease violation, little leverage |
| A co-signer or guarantor | Helps someone short of the landlord's credit or income bar | Someone else signs up for the debt, in writing |
Ways roommates can sign in Chicago, from the Illinois Legal Aid Online guides and the RLTO, read Oct 16, 2026. "Good for" and "risk" are our summary.
The rule we'd use: if a person will live there and pay rent, put them on the lease or on a written sublease, so their standing never rests on someone's memory of a conversation.
Can I sublet to a roommate in Chicago?
Who decides: the City (RLTO §5-12-120), and your lease.
When a tenant ends a lease early, the RLTO says the landlord:
"shall accept a reasonable sublease proposed by the tenant without an assessment of additional fees or charges."
"Reasonable" isn't defined, and the line sits in the paragraph about a tenant who's leaving. Whether it also covers bringing in a roommate while the original tenant stays is unsettled, so don't count on it. Also:
- Not every building is covered. Owner-occupied buildings with six or fewer units and dorm or university housing are outside the RLTO.
- Housing Choice Voucher tenants can't sublet, and subletting against a lease that bans it can get both the tenant and the subtenant evicted (Illinois Legal Aid Online).
- A "sublet" may really be a relet. In a relet, the new person applies to the landlord and the old tenant's lease ends. In a sublet, the old tenant stays responsible unless the landlord releases them.
- A lead tenant may become a landlord. The RLTO's "landlord" includes a sublessor (§5-12-030(b)), so a tenant who rents a room to a subtenant may take on some landlord duties, such as how a deposit is handled. That's our reading, with no case on it, so ask a tenant attorney before you collect a deposit.
Do we need a co-signer?
Who decides: the landlord decides whether to accept one; Illinois law decides how it's signed.
Landlords set their own credit and income bars, and they may require each roommate to qualify on their own. The bars vary, so ask for them in writing before anyone pays an application fee. When one of you falls short, a co-signer or guarantor is the usual fix.
Illinois has one firm rule: a promise to pay someone else's debt has to be in writing and signed (740 ILCS 80/1). Whether the guarantor signs the lease or a separate guaranty form is the landlord's paperwork; we found no rule on it. Ask to see the form before your guarantor signs. More on what landlords check when roommates apply together.
How do I add or replace a roommate mid-lease?
Who decides: the landlord, with fee rules from Illinois from Jan 1, 2027.
We found no Chicago or Illinois law that gives a tenant the right to add or swap a co-tenant mid-lease. A landlord can refuse a new roommate for lawful reasons, such as credit, income or rental history, judged the same way for everyone, but never because of a protected trait.
Fees change for leases entered after Jan 1, 2027 (Public Act 104-0479). Application fees over $50 are banned, with a narrow exception for a third-party check that really costs more, billed with receipts within 14 days. A fee for modifying or renewing the lease is banned, every required fee goes on page one, and renaming a fee doesn't get around the rule. Owner-occupied buildings with six or fewer units are excluded.
Still open: whether a fee to swap a roommate counts as a banned "modification" fee, and whether the incoming roommate can be charged a screening fee of $50 or less. Neither has been tested, so ask the landlord in writing what any fee is for. More in our guide to what a room costs in Chicago.
How many people can live in a Chicago apartment?
Who decides: the City, with a federal guideline. A landlord can set a lower limit if they apply it equally.
1. The building code sets floor-space minimums for the whole unit and for each bedroom (§14X-4-402.3 and .4):
| Number of people | The whole unit needs at least | A bedroom they share needs at least |
|---|---|---|
| 1 | 125 sq ft | 70 sq ft |
| 2 | 250 sq ft | 70 sq ft |
| 3 | 350 sq ft | 150 sq ft |
| 4 | 450 sq ft | 200 sq ft |
| 5 | 525 sq ft | 250 sq ft |
Chicago building code minimums, §14X-4-402.3 and .4 (amlegal copy, read Oct 16, 2026). The bedroom column counts the people over 11 sleeping in that one bedroom. Each extra person adds 75 sq ft to the unit and 50 sq ft to a bedroom; each child aged 2 to 12 adds 35 sq ft to a bedroom. The 5-person bedroom figure is our arithmetic from that rule.
These are minimums, not a landlord's cap, and they're about space, not about whether you're related.
2. Zoning defines a "household" as people related by blood, marriage, adoption or guardianship, plus no more than 3 more people, living as a single housekeeping unit (Chicago Zoning Ordinance §17-17-0270). Read plainly, that's up to 4 unrelated adults. We found no City guidance, case or enforcement record on how it's applied to rentals, so treat it as the definition on paper, not a rule you can expect to see enforced either way.
3. "Two per bedroom" is a federal guideline, not Chicago law. HUD treats it as generally reasonable when it reviews a landlord's limit, but the size of the rooms and the unit, children's ages, the layout and the building's systems can outweigh it (63 Fed. Reg. 70256, Dec 18, 1998). Federal and Illinois law both let reasonable local occupancy limits stand (775 ILCS 5/3-106).
What can a landlord ask of roommates, and what is illegal?
Who decides: the landlord sets the criteria; Chicago, Illinois and federal fair-housing law decide what's off limits.
A landlord can require everyone to be on the lease, and set occupancy rules, written and reasonable guest limits, and screening criteria applied the same way to every applicant. What a landlord can't do is refuse you or your roommate because of a protected trait, and the three lists differ:
- Chicago (Fair Housing Ordinance, §5-8-020 and -030, amended Apr 16, 2025): race, color, sex, gender identity, age, religion, disability, national origin, ancestry, sexual orientation, marital status, parental status, military status and source of income, plus actual or perceived association with someone, decisions about reproductive or gender-affirming care, and retaliation.
- Illinois (Human Rights Act, 775 ILCS 5/3-102 and 1-103): race, color, religion, national origin, ancestry, age (40 and over), sex, marital status, order of protection status, disability, military status, sexual orientation, pregnancy, reproductive health decisions and unfavorable military discharge, plus familial status, immigration status, source of income and arrest record.
- Federal (Fair Housing Act): race, color, religion, national origin, sex, familial status and disability.
Source of income is protected in Chicago and Illinois but isn't on the federal list. Illinois also bans criteria that have a discriminatory effect, unless they're necessary to a substantial, legitimate and non-discriminatory interest (775 ILCS 5/3-102(H)). The laws have narrow exemptions; among them, Chicago and Illinois allow room rentals to be restricted to one sex, and Illinois exempts an owner who lives in the home and rents out a room in it (§5-8-050(c); 775 ILCS 5/3-106).
The checklist to save before you sign together
Ask the landlord, in writing:
- One lease for all of us, or separate leases per room?
- How do you screen, and does each of us have to qualify on our own?
- If one of us leaves, how do we replace them, how long does it take, and is there a fee?
- Do you allow subletting, and how do you handle a sublease request?
- What are the guest rules, written in the lease?
- How many people may live in this unit?
- Is there a deposit or a non-refundable move-in fee, and where is a deposit held? From Jan 1, 2027, every required fee goes on page one of a new lease.
Settle between yourselves, in a roommate agreement:
- Who pays what, and by when.
- Who deals with the landlord.
- How the deposit or move-in fee is split, and who gets what back.
- What happens if someone leaves early or stops paying.
- Guest and overnight rules.
- How much notice someone gives before moving out, and how you'll find a replacement.
No Illinois law requires a roommate agreement. As we read it, it binds the two of you, not the landlord: it can't change what each of you owes under a joint lease, but it settles what you owe each other. More on what to settle before you sign. If you're still looking for the person to sign with, that's what Xzerno, the free-to-use roommate app we build in Chicago, is for: you each answer questions about how you live, and messaging opens only after you both say yes.
Red flags:
- Taking a roommate's word on their credit or income without seeing it. The landlord will check.
- Being asked for money before you've seen the lease or the unit.
- A landlord who won't put guest or occupancy rules in writing.
- A lease you can't read until you pay.
- On a lease signed after Jan 1, 2027, a required fee that isn't on page one.
- More than four unrelated adults planned for one unit.
More Chicago renting and roommate guides are on our blog.
Frequently asked questions
Does every roommate have to be on the lease in Chicago?
No Chicago or Illinois law requires it; the landlord decides, so ask whether every adult has to sign. Under the RLTO, a person living there by the landlord's written or spoken agreement is likely a tenant even without a signature (§5-12-030). Check your lease's guest and occupant clauses.
If one roommate doesn't pay, can the landlord come after me?
On one joint lease, yes. Illinois Legal Aid Online says the landlord can serve the unpaid-rent notice on everyone and bring one eviction case against all of you, and each person is responsible for bringing the whole account current. With separate leases per room, only the person who didn't pay is named. General information, not legal advice.
How many unrelated people can live in a Chicago apartment?
Chicago's zoning code defines a household as related people plus up to 3 more, which reads as up to 4 unrelated adults. We found no guidance on how the City enforces that on rentals. The building code separately sets minimum floor space per person, and a landlord can set a lower limit if they apply it equally.
Can a landlord refuse my roommate?
For lawful reasons, yes: credit, income or rental history, judged by the same criteria for every applicant. Never for a protected trait. Chicago and Illinois protect more traits than federal law does, including source of income and marital status; Chicago adds parental status, and Illinois adds immigration status and arrest record.
What fees can a landlord charge to add a roommate?
For leases entered after Jan 1, 2027, Illinois caps application fees at $50, with a narrow exception, and bans fees for modifying or renewing a lease. Whether a fee to swap a roommate counts as a banned modification fee hasn't been tested, so ask the landlord in writing what any fee is for. General information, not legal advice.
Sources
- Municipal Code of Chicagoch. 5-12, Residential Landlord and Tenant Ordinance (amlegal copy, current through Jun 17, 2026) · read Oct 16, 2026Read Oct 16, 2026
- Municipal Code of Chicagoch. 5-8, Fair Housing (amlegal copy) · read Oct 16, 2026Read Oct 16, 2026
- Chicago Zoning Ordinance§17-17-0270, household (amlegal copy) · read Oct 16, 2026Read Oct 16, 2026
- Chicago Zoning Ordinance§17-17-0102-B, household living (amlegal copy) · read Oct 16, 2026Read Oct 16, 2026
- Chicago Minimum Requirements for Existing Buildings§14X-4-402.3 and .4 (amlegal copy) · read Oct 16, 2026Read Oct 16, 2026
- Illinois Human Rights Act775 ILCS 5/3-102 · read Oct 16, 2026Read Oct 16, 2026
- Illinois Human Rights Act775 ILCS 5/3-106 · read Oct 16, 2026Read Oct 16, 2026
- Illinois Human Rights Act775 ILCS 5/1-103 · read Oct 16, 2026Read Oct 16, 2026
- Illinois Statute of Frauds740 ILCS 80/1 · read Oct 16, 2026Read Oct 16, 2026
- Illinois General AssemblyPublic Act 104-0479 (765 ILCS 705/35, effective Jan 1, 2027) · read Oct 16, 2026Read Oct 16, 2026
- HUDoccupancy standards, 63 Fed. Reg. 70256 (Dec 18, 1998) · read Oct 16, 2026Read Oct 16, 2026
- CFPBWhat is a tenant screening report? (reviewed Jul 1, 2021) · read Oct 16, 2026Read Oct 16, 2026
- Illinois Legal Aid OnlineDealing with unpaid rent (revised May 5, 2026) · read Oct 16, 2026Read Oct 16, 2026
- Illinois Legal Aid OnlineApplying for rental housing (revised Mar 25, 2026) · read Oct 16, 2026Read Oct 16, 2026
- Illinois Legal Aid OnlineAddressing lease violations (revised Feb 15, 2026) · read Oct 16, 2026Read Oct 16, 2026
- Illinois Legal Aid OnlineSpoken and written leases (revised Mar 25, 2026) · read Oct 16, 2026Read Oct 16, 2026
- Illinois State Bar AssociationYour Guide to Landlord-Tenant Law (2024) · read Oct 16, 2026Read Oct 16, 2026
- DomuIn Chicago there's no such thing as a roommate (undated) · read Oct 16, 2026Read Oct 16, 2026
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