Does an additional tenant need to meet the income qualification?

[Laura Dalton]

We have a great grad student renting our 2 bedroom duplex. He didn't meet the income requirement so his parent's co-signed. Now he'd like to find a roommate to share the costs. I understand the new tenant would need to have a credit and background check and we'd check references, but what if they are unable to meet the income qualification (assuming they can't get a co-signer)? If tenant #1 (the grad student) should leave before the end of the lease, isn't he still on the hook for the entire rent (assuming the second tenant either stops paying or only pays his half)?

If so, why do I need to ensure tenant #2 is able to pay the full amount in the event tenant #1 leaves? Our lease does say, 'jointly and severally liable'...

Would it be better for tenant #1 to sublet the 2nd bedroom and be responsible for collecting his half of the rent from the new tenant ? We'd still want to see a background check and check references to ensure the applicant is a good citizen, but do we need to care about his credit or income? In that event what paperwork do we get involved with? Or is everything done between the original lessee and the new subletting tenant?? Thanks for your help with this. Obviously we're noobs.