Domu recommends that all Chicago tenants and landlords sign a written apartment lease. But did you know that under Illinois law, residential leases need not be in writing unless the lease term is for more than a year?  (See the Statute of Frauds, 740 ILCS 80/2). Even an oral rental agreement for a term longer than a year may still be enforceable, though only as a month-to-month tenancy. See Luster v. Estate of Cohon, 11 Ill. App.3d 608 (1st. Dist. 1973). 
Let’s assume that the landlord and tenant have agreed to sign a rental lease agreement. Both parties will want that lease to be enforceable, and as such, they must both sign the agreement.  

Do Roommates All Need to Sign the Same Chicago Apartment Lease?

What about roommates? Should they both sign the apartment lease? Yes, and it benefits both the tenants and the landlords to if they do.  Let’s imagine that Tenant A signs the lease but its roommate does not. The roommate’s occupancy would be a material breach of the lease, assuming that the lease, like Domu’s model lease, states that the premises may be occupied only by Tenant A (along with his or her minor children. The unauthorized roommate’s occupancy would be a material non-compliance of the lease and would be a basis for its termination. So, roommates, make sure you are all on the lease so that you don’t get evicted!  

And as for the landlord, he or she wants all the roommates named on the lease so that the entirety of the rent may be collected from any of one of them.  This concept, called joint and several liability, means that when Roommates A and B each sign the lease as Tenants, they each take on the responsibility for paying the entirety of the rent to the landlord.  So even if Roommates A and B decide to a 60/40 split (maybe Roommate A got the larger bedroom or a better view), and Roommate B later moves out or falls on hard times, the landlord can go to Roommate A to collect the entire rent.  Some roommates find it helpful to negotiate a roommate agreement that requires each to pay her share of the rent (and perhaps to agree to other conditions, like rules and responsibilities regarding cleaning, shared food, parties, and noise) to cover themselves in this regard.

And what about guarantors? If a landlord is uncomfortable with a potential tenant’s credit score, employment history, or income, the landlord might ask the tenant to provide a guarantor. That guarantor promises to pay the landlord the entirety of the rent and any other money due under the residential lease. The guaranty must be signed in order for this promise to be enforceable.  You can find Domu’s guaranty provision at the end of Domu’s model apartment lease

The general information that Domu provides about Chicago landlord tenant law is not intended as legal advice. Domu endeavors to provide accurate information, but the law is subject to change, and Domu is not a law firm or provider of legal services. Questions about your particular leasing situation should be directed to a lawyer.