Roommates, Sublets, and Airbnb Requests: How Landlords Should Answer "Can Someone Else Move In?"

Sooner or later every landlord gets the text: "Hey, my girlfriend is going to move in with me" or "I'm doing a work rotation in Denver for five months — can I sublet?" How you answer determines whether you keep a clean, enforceable lease or quietly end up with an unscreened stranger living in your property with no signature, no deposit, and no liability. The good news: occupancy change requests are one of the easiest landlord problems to systematize, because almost every version of them can be routed into one of four decisions.

First, know the difference between the four requests

Tenants use the words "roommate," "sublet," and "guest" interchangeably. You can't. Each one changes your legal relationship differently, and your response should differ too.

• Adding an occupant/co-tenant: a new adult joins the household and signs the lease. Everyone becomes jointly and severally liable. This is usually your best outcome.
• Subletting: your tenant rents the unit (or a room) to someone else and collects rent from them. Your original tenant stays on the hook, but the person actually living there has no contract with you.
• Assignment: the original tenant transfers the entire lease and walks away. This is effectively a mid-lease tenant replacement.
• Long-term guest: someone who technically hasn't "moved in" but has been there for six weeks with a key and a mail forward. This is the category tenants hide inside.

The person you should worry about isn't the roommate who asks permission. It's the one who moves in without asking — because if you learn about them late and keep collecting rent, you may have created a tenancy you never screened.

Your lease should already answer this

If your lease doesn't have a tight occupancy clause, every one of these conversations becomes a negotiation instead of a policy. A workable clause covers five things:

1. Named occupants. List every adult and minor by name. "The premises shall be occupied only by the following persons…" removes ambiguity later.
2. A guest limit. Something like: no guest may stay more than 14 consecutive nights, or 21 nights in any 6-month period, without written landlord consent.
3. Written-consent requirement. No subletting, assignment, or added occupant without your prior written approval, and approval requires an application and screening.
4. Short-term rental ban. Explicitly prohibit listing the unit or any part of it on Airbnb, Vrbo, or similar platforms. Generic "no subletting" language gets argued about; naming the platforms does not.
5. Application fee and rent adjustment. State that an added occupant triggers a screening fee and, where allowed, an occupancy-based rent adjustment or added deposit.

One caution: several jurisdictions limit how absolutely you can say no. New York's roommate law lets a tenant add one occupant plus dependents. California's Civil Code 1946.2-adjacent rules and local ordinances in cities like San Francisco give tenants rights to add certain household members. Some states require that consent be withheld only for reasonable cause. So write your clause as a process ("must apply and be approved") rather than a flat prohibition — a process survives legal scrutiny far better than a blanket ban.

The roommate addition: screen them like any applicant

When a tenant wants to add an adult, treat that person as a new applicant, full stop. Skipping screening because "they're already basically living there" is how landlords end up with an evicted-twice co-tenant on a lease they can't get out of.

Run the same process, same standards

• Full rental application, ID, and income verification.
• Credit, eviction, and criminal background per your written criteria — the same criteria you use for everyone, applied the same way. Inconsistency here is a fair housing problem, not just a paperwork problem.
• Income test on the household, not the individual. If your standard is 3x rent, a household of two making a combined 3.4x passes even if neither passes alone.
• Reference check with prior landlords if the applicant has rental history.

Then paper it correctly

Do not just add a name to your file. Execute one of these:

• Lease amendment / addendum signed by you, the existing tenant(s), and the new occupant, stating the new occupant is a co-tenant jointly and severally liable for all lease obligations from the effective date.
• Or a brand-new lease with all parties, which is cleaner if you're near renewal anyway.

The joint-and-several language matters enormously. Without it, if the couple splits and one leaves, you may only be able to pursue whoever technically signed. With it, either tenant owes the full rent.

Handle the deposit before they move a box

Adding an occupant often means you'd like a bit more deposit. Whether you can collect it mid-lease depends on your state's cap and on whether your lease permits it. Many states limit total deposits to one or two months' rent regardless of how many people live there, and the return deadline and itemization rules stay the same. Check your state's limit against the current rules in our security deposit laws by state reference before you ask for another dime — in California, for example, the cap tightened significantly and there's no "extra roommate" exception.

Also decide, in writing, who gets the deposit refund. The cleanest approach: the deposit stays with the unit, the refund goes to whoever is on the lease at move-out, and roommates settle internally among themselves. Put that sentence in the addendum and you'll never referee a roommate breakup.

The sublet request: usually say "no, but here's what I can do"

Subletting is bad for landlords in a specific way: you get an occupant you didn't approve, and the person with the contract isn't the person breaking the toilet. Unless your state requires you to allow it (some do, on reasonable terms, especially in New York), offer alternatives instead of a flat refusal:

• Assignment with a full replacement tenant. The new person applies, gets screened, and signs a new lease. The departing tenant signs a release effective on the new lease start date, and forfeits nothing if the transition is clean.
• Approved sublease with the subtenant as co-signer of an addendum. If you allow it, make the subtenant sign an agreement directly with you acknowledging your rules, your right to enter, and your right to pursue them for damages. Keep the original tenant fully liable.
• Early termination for a fee. Sometimes the honest answer is that the tenant should just leave. A defined buyout (commonly one to two months' rent, or actual re-rental costs) beats five months of a stranger you never met.

If you do approve a sublease, add a rule that the sublease rent may not exceed what the tenant pays you. Profiteering sublets are how a tenant turns your unit into their business.

Short-term rental requests are a different animal

Airbnb subletting isn't a roommate question, it's an insurance and liability question. Your landlord policy almost certainly excludes commercial short-term lodging; a guest injury could leave you uncovered. Many cities also require the host to be the property owner or a registered primary resident, meaning your tenant's listing may be illegally operated in your name. Deny these, cite the lease clause and the insurance exclusion, and check the platform for your address if you suspect it's already happening.

When someone already moved in without asking

Move fast and in writing. The longer you accept rent knowing an unauthorized adult is living there, the stronger their argument that you consented.

1. Document what you know: dates, observations, neighbor reports, vehicles, mail, utility name changes. Facts, not accusations.
2. Send a notice to cure. Cite the occupancy clause, state the violation, and give the tenant a clear choice with a deadline: submit an application for the occupant, or the occupant vacates.
3. Offer the compliant path first. Most of these situations resolve with a screening application and a $200 addendum. Eviction over an unauthorized girlfriend is expensive theater.
4. Escalate only if ignored. If they neither apply nor remove the occupant, the lease violation is documented and you have a real record — which is the only thing that matters if you end up in front of a judge.

Build it into your workflow, not your memory

Occupancy changes are frequent enough that they deserve a saved process. A simple one:

• A standing reply template that explains the four options and links your application.
• Written screening criteria you apply to every added occupant identically.
• A pre-drafted occupancy addendum with blanks for name, effective date, and deposit terms.
• An updated unit record showing every current adult occupant, so your renewal notices, inspections, and deposit accounting all reflect reality.

Key takeaways

• Roommate, sublet, assignment, and long-term guest are four different legal situations — sort the request before you answer it.
• Write your occupancy clause as an approval process, not a blanket ban; bans get struck down, processes hold up.
• Screen every added adult with the same written criteria you use for new applicants, and make them sign on as a jointly and severally liable co-tenant.
• Check your state's deposit cap before collecting extra money for an added occupant, and specify in writing that the refund follows the lease, not the roommate.
• Counter sublet requests with assignment or a defined early-termination fee; deny short-term rental subletting on insurance grounds.
• If someone moved in without permission, send a notice to cure quickly — continued acceptance of rent looks like consent.

Frequently asked questions

Can I refuse to add a tenant's spouse or partner to the lease?

You can require them to apply and meet your screening criteria, but refusing solely because of marital status or familial status risks a fair housing claim, and some states and cities expressly grant tenants the right to add a spouse or one additional occupant. Refuse based on documented criteria failures — not on who the person is to your tenant.

Can I raise the rent when a roommate moves in?

Only if your lease provides for it, or at the next lawful renewal with proper notice. Mid-lease, the rent is the rent unless a clause ties it to occupancy count. Going forward, add an occupancy-adjustment clause so the extra water, wear, and turnover cost isn't yours to absorb by default.

How long can a guest stay before they're legally a tenant?

There's no universal number, which is exactly why your lease needs one. 14 consecutive nights or 21 nights in six months is a common, defensible standard. What creates tenancy in practice is your behavior: accepting rent from the person, giving them a key, or naming them on utilities.

Does a subtenant have rights against me as the landlord?

Generally a subtenant's contract is with your tenant, not with you, so they have limited direct rights — but many courts still extend habitability protections to anyone lawfully occupying the unit, and unauthorized occupants can be hard to remove quickly. That asymmetry is the main reason to prefer assignment over subletting.

The bottom line

Occupancy changes are not an interruption to being a landlord — they're a regular part of it. Landlords who handle them badly do it by improvising over text message; landlords who handle them well have a template, a screening standard, and an addendum ready to send the same day the question arrives. Rentmark keeps your screening criteria, lease documents, addenda, occupant records, and deposit accounting in one place, so adding a roommate takes ten minutes instead of turning into a year of ambiguity. You can try the live demo without creating an account and see how the paperwork trail comes together.