If three roommates can each afford, say, $500 in monthly rent, that doesn't guarantee they can share a $1,500 apartment. Landlords prefer each tenant can afford the place on her own, without roommates. That way if any of the roommates leave, the remaining tenants can still afford to cover the rent.
It's up to the landlord to decide how much a renter needs to make to qualify for a given amount of rent. A common rule of thumb is that you need a monthly income close to three times what your monthly rent will be, but that's not universal. In New York City, landlords are more likely to require about 3.3 times the monthly rent. A landlord can accept roommates' combined income when making the call, but he doesn't usually have to.
A landlord who uses a double standard may cross a legal line. Landlords can't discriminate based on your race, religion, nationality or disability and that includes setting different rules for different tenants. A landlord can't allow, say, two white tenants to combine their income, then demand that two black tenants qualify individually. In many states a landlord can, however, let married couples apply with combined income but not two singles. Some states, such as California, don't allow that.
If your landlord won't let you combine income, one option is to look for a co-signer or guarantor. This is someone who'll put his name on the rental agreement as the person responsible if the rent isn't paid -- one of your parents, for example. The income requirement for cosigners is usually higher than for tenants. Your landlord doesn't have to accept cosigners, however. Some landlords figure that trying to collect from someone who doesn't live there is too much work.
Income is only one piece of the application puzzle. Your landlord's probably going to check your credit histories as well, and whether you've skipped out on rent at other apartments. If your credit is poor, having enough income may not help. The landlord can't legally refuse you because of your income source, though. If you get veterans' benefits or Social Security survivor benefits, for instance, the landlord can't say no just because the money didn't come from your wages.
A Durham, NC resident, Fraser has written about law, starting a business, balancing your budget and fighting evictions, among other legal and financial topics.