Are both roommates on the lease?

If yes, both are co-tenants with joint and several liability. The landlord typically can't pick one to evict without also affecting the other — UD generally proceeds against the whole tenancy.

What if one roommate is on the lease and the other isn't?

The on-lease tenant is the master tenant; the off-lease occupant is either an unauthorized occupant (landlord's lease-violation claim) or a subtenant (master tenant's responsibility to evict). The path depends on who's pursuing removal.

Can one roommate evict another?

Master tenant can evict a subtenant through their own UD action — master tenant essentially becomes the landlord vs the subtenant. Same procedural rules apply: notice, file, summons, answer, trial.

What about partner-as-roommate scenarios?

Relationship dynamics often complicate roommate removal. Domestic violence concerns may trigger §1946.7 / §1941.5 protections. If the relationship involves DV, special procedures apply. Otherwise standard subtenant/co-tenant analysis.

What about written roommate agreements?

Strongly recommended. Written agreements between roommates cover rent allocation, shared expenses, move-out notice, and termination procedures. They don't override the lease but they clarify rights between roommates.

Co-tenant vs subtenant

Evicting a roommate. Who's on the lease decides the path.

Both on lease = co-tenants, UD affects both. One on, one off = master-tenant vs subtenant, master tenant runs their own UD. Watch for DV protections.

TL;DR

Both on lease = joint co-tenants, UD generally against both. One on lease = master tenant vs subtenant, master tenant runs UD against subtenant. DV protections apply to romantic partners. Written roommate agreements clarify rights.

Roommates & Co-Tenants
Unauthorized Occupant
DV Protections

Common questions — evicting a roommate

Both on lease?

Co-tenants. UD affects both.

One on, one off?

Master tenant vs subtenant. Master tenant runs own UD.

Roommate evict roommate?

Master tenant can UD a subtenant.

Partner scenarios?

DV protections may apply.

Roommate agreements?

Recommended. Don't override lease but clarify between-roommate rights.