Do I need a written agreement to protect myself when leasing a room in a house from a tenant who has been living there for the past year? I don't want to face a sudden eviction because I don't have a proper legal contract.
While oral leases and rental agreements are valid and enforceable for up to one year, it's always better to use a written rental agreement. Writing down the key aspects of the arrangement, such as the rent, when it's due, and the amount of the deposit, will avoid misunderstandings down the road.
The most important function of a written agreement is that it will force the landlord and tenant to decide whether they're entering into a month-to-month rental agreement (which self-renews unless one side decides to terminate), or a lease (which runs to a certain ending date).
Whether you'd be better served by a monthly arrangement or a lease will depend on several factors. Most importantly, remember that you'll be living with someone, and will want to enjoy a peaceful, welcoming atmosphere. Having chosen this rental, you're doubtless expecting that it will be fine, but as you no doubt know, sometimes things don't work out as you expected. If that happens, you may want to be able to terminate and leave without responsibility for future rent—something possible only with a monthly agreement. On the other hand, if you want the certainty that you can stay in the rental for a set period of time, a lease might be the way to go.
Keep in mind that even with a lease, you can be asked to leave (and evicted if necessary), if you break an important lease term (such as bringing in a pet), fail to pay the rent, or conduct illegal activities on the premises. And understand that if the tenant who lives there now is renting month-to-month, you'll have to move out if the landlord terminates his rental agreement.
The rental situation you've described has you renting from a tenant, who rents from the landlord. In legal lingo, you're a subtenant. Most leases require the landlord's consent before a tenant can rent to a subtenant. The reason is simple enough: Landlords want to know who's living in their properties; they want to screen out poor business risks. Landlords also don't want a situation where the tenant is charging a sizeable amount for the subrental, effectively making money by using the landlord's property.
It's very important to ask the tenant to show you his or her lease or rental agreement. Even without a "no subletting without consent" clause, doing so without involving the landlord might be contrary to state law.
To properly sublet, you'll need the consent of the landlord. Be prepared with a credit report, pay stubs, references, and so on—the same materials you'd bring to any prospective landlord.
Don't be tempted to skip this step, thinking that the landlord will never find out, or won't care. If the deal is done under the table and the landlord doesn't like it when he learns of it, that could be the end of your tenancy right there. Whether you have a written or oral rental agreement or lease will be quite beside the point.