Most landlords require all adults living in a rental to sign the lease or rental agreement. In addition, most leases and rental agreements explicitly prohibit non-signers from living in the rental, and limit the number of days that guests may stay at the property. Assuming your lease or rental agreement contains similar provisions, your landlord may terminate your tenancy (and possibly evict you) for bringing in unauthorized roommates and subtenants. (A subtenant is someone who subleases or rents all or part of the rental premises from a tenant, not from the landlord.)
Despite the fact that they might be violating their lease or rental agreement, it's not uncommon for tenants to have a friend or significant other move into their rental unit without the landlord's knowledge. Alternatively, landlords sometimes allow a boyfriend or girlfriend to move in without signing the lease (or they turn a blind eye to the arrangement). In some areas, even guests who overstay their welcome might become legal tenants (even when they don't sign a lease or rental agreement), simply by virtue of the length of their stay.
So what do you do when you want a roommate who's not on the lease or rental agreement to move out?
Removing an unauthorized roommate who doesn't want to leave can be challenging. Under many laws, all occupants—even those whose presence wasn't authorized by the landlord—have certain rights to remain at a rental, especially when they've lived there for a long time.
You need to let your roommate know—in writing—that you are ending the current living arrangement. Give a deadline by which the roommate (and the roommate's personal property) must be out of the rental. Even though the roommate isn't an official tenant, you should give at least the same amount of notice required to end a month-to-month tenancy. In most states, the notice period is 30 days. Make sure that your roommate receives the notice: As silly as it might seem given that you live together, consider mailing the notice via certified mail for proof of receipt. Keep a copy of the notice for yourself.
If your roommate ignores your notice and remains in the rental, you might have to file an eviction lawsuit. In general, the procedures for evicting a resident who isn't a party to the lease or rental agreement will be the same as those for official tenants, but your state or local laws might be an exception. A local landlord-tenant attorney can help you navigate how to proceed in your area's courts. Keep in mind that—regardless of the roommate's status on the lease or rental agreement—it is never legal to physically remove or lock out a tenant (or a roommate who might have legal rights similar to a tenant's) from a rental.
Even when your landlord approves a subtenancy, removing the subtenant can be challenging. Depending on the terms of your lease or rental agreement, you might be solely responsible for terminating the subtenancy. If the subtenant doesn't leave voluntarily, you might also have to file an eviction lawsuit on your own.
Evicting a subtenant can be especially difficult when you don't have a written subtenancy agreement covering issues such as termination and eviction rules and procedures. It can be especially complex if the property is rent-controlled and requires "just cause" (a good reason) to evict. In any case, eviction lawsuits can be an expensive and time-consuming process.
Depending on your relationship, you might consider enlisting your landlord's help in removing the unwanted roommate—especially when the landlord approved a subtenancy or was aware of the roommate. However, if you brought in an occupant in violation of a clause in your lease or rental agreement (such as a no-long-term-guests clause or a no-subletting clause), your landlord might simply terminate your tenancy to be rid of the problem.
Even if your landlord would like to help you remove your roommate, your landlord might ultimately decide there's no viable solution other than to evict all people living in the rental and start fresh with a new tenant.
Due to the complexity of getting rid of an unauthorized occupant in your rental, consider consulting with a local landlord-tenant attorney before taking any action. As discussed above, state, local, and rent control laws vary greatly, and often just one misstep under the law can set you back to square one in the process of removing a roommate.
If your roommate is abusing you or you are concerned that your roommate is going to harm you, contact the police for information on temporary restraining orders and communicate your fears to your landlord. Some laws give special protections to tenants who are victims of domestic violence.
When looking for help as a victim of abuse, remember to consider how private your computer, Internet, and phone use are. Consider whether there's anything you can and should do to prevent someone else from learning that you're doing research or seeking help. Some victims, for instance, might use the same computer or device as the abuser or might have a phone plan that allows the abuser to see the calls they make and receive. Other kinds of technology, like home security cameras and GPS in phones and cars, can also allow for monitoring by the abuser.