I'm looking to rent a property with my partner, but their credit is not great (lower than 650). Do they need to be on the lease too or can I rent the apartment and allow them to live with me?
In Virginia there is a distinction between a tenant and an authorized occupant. An authorized occupant is
a person entitled to occupy a dwelling unit with the consent of the landlord, but who has not signed the rental agreement and therefore does not have the financial obligations as a tenant under the rental agreement.
A tenant is
a person entitled only under the terms of a rental agreement to occupy a dwelling unit to the exclusion of others and shall include roomer.
There is a third category, guest or invitee which
means a person, other than the tenant or person authorized by the landlord to occupy the premises, who has the permission of the tenant to visit but not to occupy the premises.
Such people who live there would not be invitees.
Clearly, you can have others living with you who are not on the lease, if the landlord agrees. The landlord's main concern regarding credit rating is probably financial responsibility, and if you qualify, having people live with you who have low or no credit rating is unlikely to make any difference. There may be other concerns, such as background checks or increases utility costs).
Virginia law does not specifically allow "unauthorized occupants", i.e. occupants not approved by the landlord, nor does it specifically disallow such occupants. Leases often include a provision that addresses this matter, prohibiting unauthorized occupants. Supposing that the lease is silent on the matter (not likely) and the landlord wanted to compel the other occupants to leave, the procedure would be to tell the tenant that the unauthorized occupants must leave. Then if you do not comply (do not get them to move out), the landlord could start the procedure of evicting the lot of you, and the question would be whether the court would find that you have a right to let unauthorized other people live with you. I can't find any applicable case law, but it is unlikely that the court would find such a right. Tenants have special statutory rights, as do authorized occupants under the Virginia Residential Landlord and Tenant Act. A court would not find that the rights of an authorized occupant extend to an unauthorized occupant, which means that the landlord's rights as property owner are dispositive of the matter.