Do I have to allow a tenant to add a roommate?

Not unless your lease says so. The lease names specific tenants and limits occupancy. A new occupant requires landlord approval. You can decline for any non-discriminatory reason: failed screening, occupancy limits, or simply preferring not to add liability.

Should the new roommate sign the original lease or a new one?

A lease amendment is cleanest. The new roommate signs the amendment, which makes them a co-tenant on the existing lease for the remaining term. Joint-and-several liability puts every tenant on the hook for the full rent.

Do I have to screen the new roommate?

You should. Run the same credit, background, and income checks you ran on the original tenant. If you skip screening for the new roommate but did it for the original, you create a Fair Housing exposure if the new roommate later defaults and you try to enforce against everyone.

Can I increase the security deposit?

Often yes, within state caps. Adding an occupant increases wear-and-tear risk. Most leases let you collect an additional deposit prorated for the remaining term. Check your state cap (one or two months' rent total in many states).

What about rent? Should it go up?

You can raise rent to reflect added occupancy if your lease allows or you do it through a new lease. In rent-controlled jurisdictions you may have stricter limits. Out of fairness many landlords keep rent the same and let the roommates split it.

Adding a Roommate Mid-Lease

A tenant texts: "Hey, my friend wants to move in next month, is that cool?" The right answer is "let me send you the application." Adding a roommate mid-lease is a normal request, but only if it goes through the same process you used for the original tenant.

Why the lease language matters

Your lease names specific occupants. Anyone living there beyond the named tenants and their minor children is an unauthorized occupant. The lease should:

List all permitted occupants by name
Require written landlord approval before adding any new occupant
State that all rent-paying occupants must sign as tenants (joint and several liability)
Allow guests for a limited time only (often 14 days in any 6-month period)

The five-step process

1. Tenant submits the request in writing. Email is fine. Get the prospective roommate\'s name, contact info, and intended move-in date.

2. Prospective roommate completes a rental application. Same form, same fees as a new tenant.

3. You run the same screening. Credit, background, eviction history, income verification. Apply the same criteria.

4. You issue an approval or denial. Approved: send the lease amendment for signature. Denied: provide adverse action notice if the denial was based on a credit report.

5. Lease amendment is signed. All existing tenants plus the new roommate plus you. Updated occupancy list, joint-and-several liability, any rent or deposit adjustments.

Lease amendment vs new lease

Lease amendment (recommended for mid-term additions): adds the new roommate to the existing lease, keeps the same end date, joint and several liability with all tenants, no rent reset.

New lease: replaces the existing lease, resets the term, lets you reset rent and terms. Useful if the original lease is close to renewal anyway.

What the amendment should say

Reference the original lease (date, address, parties)
Add the new roommate as a co-tenant effective a specific date
State that all tenants are jointly and severally liable for rent and damages
Update the security deposit if you are collecting more
State that all other terms of the original lease remain in effect
Signed by all existing tenants, the new roommate, and the landlord

Screening: how to apply criteria fairly

Use the same written criteria you use for new applicants. Common standards:

Combined household income at least 3x rent (with the new roommate factored in)
Credit score above your minimum (e.g., 600+)
No evictions in the last 5 years
No felony convictions in the last X years (HUD guidance prohibits blanket bans, must consider individualized review)

Document the criteria. Apply them consistently. Adverse-action letters when you deny based on credit.

Joint and several liability - the key clause

"Joint and several" means each tenant is responsible for the full rent and full damages, not just their share. If one roommate stops paying, the others owe the full rent. If one trashes the place, all are on the hook.

Without this clause, you may have to chase each tenant for their proportional share. With it, you can collect the full amount from any one of them. Almost every landlord-favorable lease includes joint-and-several liability.

Security deposit adjustments

If your state caps deposits at one month, you may already be at the cap. If you can collect more:

Calculate the additional deposit (often half a month or a full month)
Document who paid what (this matters at move-out)
Update your deposit ledger
Note in the amendment that the additional deposit becomes part of the existing deposit

What if the original tenant moves out and the roommate stays?

Two paths:

Lease assignment: the original tenant transfers their interest to the roommate. Original tenant is released from liability. Requires landlord written consent in most leases.
Original tenant remains liable: they move out but stay on the lease (and the deposit return) until the term ends. Common when the original tenant is the one with stronger credit.

Get the documentation right at the time of the change, not at move-out when memories conflict.

Couples, families, and the "occupants vs tenants" distinction

Spouses and partners moving in are usually added as tenants, since they will be paying rent and have lease rights. Children and short-term guests are occupants, not tenants. Roommates almost always should be tenants - they pay rent, they have a key, they should be on the lease.

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