Can your landlord veto your new roommate?
Start with the lease. It may require consent for a new occupant, set occupancy limits, or specify an application process. In San Francisco, Rent Ordinance rules can affect a tenant’s ability to replace a departing roommate or add an occupant, but the details depend on the tenancy and agreement.
Make the request in writing and keep the landlord’s response. Do not conceal an occupant merely because the answer is inconvenient; an unauthorized arrangement can create serious risk.
Because this issue is fact-specific, contact the San Francisco Rent Board or a tenant lawyer before assuming a landlord can—or cannot—refuse a particular person.
Source: SF Rent Board guidance.