A tenant signed your lease eight months ago. Lately there’s a second car in the spot every night, a second name started showing up on the mail, and the person who answered the door when you came by for the gutter repair clearly lives there. They’re not on the lease. You never approved them. And now you have a decision to make that a surprising number of otherwise careful landlords get wrong — in both directions.
Get it wrong one way and you let it ride, because confronting people is uncomfortable and the rent is still coming in. Months later you discover that the “guest” has quietly acquired the rights of a tenant, and the easy conversation you skipped has become a formal eviction you can’t avoid. Get it wrong the other way and you take matters into your own hands — change the locks, pull a name off the parking permit, stop answering maintenance calls until they leave — and you discover that even though you own the place and you’re right about the violation, you just committed an illegal eviction and you’re the one writing the check.
The correct path runs between those two, and it’s narrower than it looks. This guide walks it end to end: how to tell a guest from an unauthorized occupant from a sublet, why you can’t simply remove someone who never signed anything, the document-first escalation that actually ends it, a notice framework, a decision table, and the special cases (the partner, the adult kid, the new baby, the Airbnb) that have their own rules.
Lease violations · ~12 min readFirst, classify what you’re actually dealing with
“Someone is living there who isn’t on the lease” is three different problems wearing the same coat. Before you draft a single notice, decide which one you have, because the response is different for each.
1. An occasional guest. Your lease almost certainly allows guests, up to a limit. The standard clause reads something like “no guest may stay more than 14 days in any 60-day period without written permission.” A partner who stays four nights a week, a parent visiting for a long weekend, a friend crashing for a week between leases — if they’re under your lease’s limit, there is nothing to enforce and nothing to do. Resist the urge to police normal life. A lease that forbids overnight guests is both unenforceable in spirit and a great way to lose a good tenant.
2. A long-term guest who has crossed the line. This is the one that matters. The partner who “stays over a lot” but whose entire life is now in the unit. The cousin who came for two weeks in March and is still there in June. The adult child who moved back home. These have stopped being guests under your own lease’s definition, and they are the situation where delay is genuinely dangerous, for the reason covered in the next section.
3. An unauthorized sublet. Here your tenant isn’t just letting someone stay — they’ve handed over possession, usually for money. A roommate they’re charging without telling you, a full sublease while they live somewhere else, or the unit quietly turned into a short-term rental on Airbnb. This is a different and usually more serious violation, because your actual tenant may have moved out, the occupant has never been screened by you, and your lease almost certainly has a separate, stricter anti-subletting clause. It warrants faster, firmer escalation, and if the original tenant is fully out of possession, it’s worth a call to counsel.
The same fact — an extra body in the unit — sits in all three buckets. Your job is to figure out which, because buckets two and three are violations you act on, and bucket one is daily life you leave alone.
Why you can’t just make them leave (the trap on both sides)
This is the part that turns a simple lease issue into an expensive one, and it cuts in two opposite directions.
The slow trap: a guest can become a tenant. Stay long enough, with your knowledge, and a guest acquires the legal rights of a tenant — even though they never signed anything and never paid you a dime directly. The line isn’t a fixed number of nights; it’s the substance of the arrangement. Courts and many state statutes look at whether the person receives mail at the unit, keeps their belongings there, has a key, has exclusive use of space, contributes to rent, and has stayed continuously. Some states treat roughly 30 days of continuous occupancy as a signal, but the safe assumption is that the line arrives sooner than you’d expect. Once it’s crossed, you can no longer simply ask the person to leave — you have to remove them through the formal eviction process, like any other tenant. Every month you let an unauthorized occupant ride is a month you may be giving away your easy options. That’s the real cost of “I didn’t want to make it awkward.”
The fast trap: self-help eviction. The opposite mistake is worse. Because the occupant never signed the lease, it’s tempting to treat them as a trespasser you can simply remove — change the locks while they’re out, take their belongings, shut off the utilities, or quietly stop doing repairs until they get the message. In nearly every state, all of those are illegal “self-help” evictions, and they flip the liability onto you instantly. The penalties are often statutory (a fixed multiple of rent, or a per-day fine), plus actual damages and sometimes the tenant’s attorney’s fees. Landlords who are completely correct about the underlying violation routinely lose money here purely because of how they tried to fix it.
And notice who you actually deal with: not the occupant, but your tenant. It’s the tenant who agreed to the occupancy clause and the tenant who is in breach of it. So every step below is addressed to the person who signed the lease, even though the body in the unit belongs to someone else. That single reframing keeps you on the legal path.
The document-first response
The way you avoid both traps is to move deliberately and put everything on paper, in order. Here’s the ladder.
Step 1: Document the occupancy before you say a word
You’re about to make a claim — “a person has moved in who isn’t on the lease” — and the tenant’s first move will be to deny it (“that’s just my friend visiting”). Win that argument in advance by documenting the reality before you raise it. Capture, with dates:
- What you’ve observed and when. The vehicle in the spot every night for three weeks. The person present, clearly settled in, during a scheduled maintenance visit. Be specific and factual; avoid speculation.
- Objective indicators. A second name appearing on the mailbox or packages. A name added to a buzzer or utility account. A social post or listing (especially for a suspected sublet or Airbnb) tying the person to the address.
- Communications. Any text or email where the tenant references the person living there, asks about adding a roommate, or explains the situation.
The goal isn’t surveillance — it’s a dated, factual record that turns “I think someone moved in” into “here is what’s been true since the 3rd.” That record is the spine of every step that follows, and it’s exactly the kind of incident documentation covered in how to document a lease violation properly.
Step 2: Raise it in writing, citing the specific clause
Have a normal conversation if you like, but the moment that matters is the written notice. It should:
- Identify the clause. Quote the occupancy/guest provision by section number. “Section 7 limits occupancy to the named leaseholders and permits guests no more than 14 days in any 60-day period.”
- State the facts plainly. What you’ve observed, with dates, without accusation or editorializing.
- Offer a real choice (see Step 3). A notice that only says “stop violating the lease” with no path forward tends to stall. A notice that hands the tenant two clean options gets resolved.
- Set a deadline consistent with your state’s cure period and your lease.
This is your notice to cure — the formal “fix this or here’s what comes next” step. If you’re unsure how to structure or time it, the notice to cure guide covers the mechanics state by state.
Step 3: Give the tenant a genuine choice
A good unauthorized-occupant notice doesn’t just demand removal — it offers the legitimate alternative, because in most cases the right outcome is to bring the occupant onto the lease, not to fight about them. The two paths:
- Add the occupant to the lease. Have the person complete a full rental application and screen them on the exact same criteria you apply to every applicant — income, credit, background, references. If they qualify, add them with a written lease amendment, adjust rent or deposit if your lease and local law allow, and you’re done. You’ve converted a violation into a properly screened, properly documented leaseholder. This is the best outcome for everyone and it’s where most of these should land.
- The occupant moves out by the deadline. If the tenant declines to add them, or the person fails screening on your consistent criteria, the occupancy clause stands and the extra person has to go by the date in the notice.
Offering the application path matters legally as well as practically: it shows you enforced the lease’s terms rather than targeting a particular person, which is your best protection against a fair housing complaint.
Step 4: Escalate only if they refuse both
If the deadline passes with no application and no departure, you’re now in standard lease-enforcement territory. Depending on your state and lease, that means either a formal cure-or-quit process, a non-renewal at the end of the term, or — if the breach is continuing and serious — eviction for breach of the occupancy clause. Ending a tenancy cleanly at term, without an eviction on anyone’s record, is often the smoothest exit; the lease non-renewal guide walks the just-cause traps that can block it. The point is that escalation is the last rung, reached only after a documented offer the tenant declined.
A decision table for the common scenarios
Every unauthorized-occupant case is some version of the same question — guest, add-to-lease, or out — but the trigger and first move shift with the facts. Use this to place the situation fast.
| Scenario | How to confirm it | First move | Escalate when |
|---|---|---|---|
| Frequent overnight guest, under lease limit | Count nights against your guest clause | Nothing — this is allowed | Only if they cross the stated limit |
| Partner / friend clearly moved in | Mail, belongings, daily presence vs. guest-clause language | Notice citing occupancy clause; offer add-to-lease application | Tenant refuses to add and person won’t leave |
| Adult child or relative moved back | Same as above; confirm they’re an adult occupant | Offer to add to lease; screen on standard criteria | Refusal to add or to vacate by deadline |
| New baby / minor child | No action needed — protected familial status | None; do not count against occupancy to push out | N/A — enforcement here risks a fair housing claim |
| Unauthorized roommate being charged rent | Payment evidence, second person settled in | Notice citing sublet/occupancy clauses; require screening or removal | Tenant won’t regularize or end the arrangement |
| Full unauthorized sublet (tenant moved out) | Original tenant absent, new person in possession | Notice citing anti-sublet clause; involve counsel | Tenant out of possession; treat as serious breach |
| Short-term rental / Airbnb operation | Online listing, guest turnover, lockboxes | Notice citing anti-sublet/STR clause; firm, fast escalation | Any continuation after notice |
The special cases that have their own rules
A few situations carry extra legal weight and deserve their own handling.
A new baby or a minor child. This is not a violation, full stop. Familial status is a protected class under the federal Fair Housing Act, which means you cannot treat the arrival of a child as a breach, refuse to renew over it, or use an occupancy limit as a pretext to move a family out. A child generally does not even count the same way against occupancy standards. If your “unauthorized occupant” is a newborn, there is no enforcement action — there’s a congratulations card.
A romantic partner or spouse. Procedurally identical to any add-to-lease case: offer the application, screen on consistent criteria, add them if they qualify. The pitfall is selective enforcement. If you let other tenants’ partners move in without a fuss but crack down on this one, you’ve created the appearance of discrimination. Apply the same rule to everyone and document that you did.
Occupancy limits — handle with care. Landlords reach for “two persons per bedroom” as if it’s a hard legal cap. It isn’t. That figure traces to federal guidance (the HUD Keating memo) and is a reasonableness starting point that flexes with unit and bedroom size, the configuration of the space, the ages of occupants, and state or local law that’s sometimes more permissive. Worse, leaning on a headcount runs straight into familial-status protection. The durable basis for action is your lease’s occupancy and guest clauses plus the documented conduct — an unscreened adult who moved in without being added — not the raw number of people in the unit. Cite the clause and the facts; keep any occupancy-limit argument secondary and consistent.
The sublet / short-term rental. When the original tenant has handed over possession for money, you’re past the friendly add-to-lease conversation. The occupant has no relationship or screening with you, your tenant may have abandoned the unit, and your anti-subletting clause is the controlling term. Escalate firmly and promptly, and if the leaseholder is entirely out of possession, get counsel involved — this can shade into questions about who is actually in possession and what process is required to remove them. The squatter removal playbook covers the harder end of that spectrum, where the person in the unit has no agreement with you at all.
What this looks like to the tenant
The reason a structured record resolves these cleanly is that the tenant experiences it as fair and inevitable, not arbitrary. Instead of a tense doorstep argument, they get a clear written notice that names the clause they agreed to, states what you observed, and offers a real way to fix it — usually “have them apply, and if they qualify they’re on the lease.” Most tenants take the easy path when there is one. The portal below is the same flow DiscoveryMark uses to put that record and notice in front of a tenant in a way that’s hard to ignore and easy to act on.
The documentation backbone
Strip away the variations and one thing decides every unauthorized-occupant case: whether you documented the occupancy at the time, or are trying to reconstruct it after the tenant has denied it. Four habits make the difference.
1. Capture the occupancy as you observe it, dated. The vehicle, the mail, the person clearly settled in during a scheduled visit — logged with dates as you see it, not assembled from memory three months later when it’s contested.
2. Cite the exact clause, in writing. “Someone moved in” is a complaint. “This violates Section 7’s occupancy limit, here are the dates” is a case. Quote the provision and attach it.
3. Offer the path and record that you offered it. The application, the screening, the chance to be added — documenting that you offered the legitimate route is what shows you enforced the lease rather than targeting a person, and it’s your strongest fair housing protection.
4. Keep it all in one timeline. Observations, the notice, the tenant’s response, the screening outcome, the cure deadline, the resolution. When this lands in front of a judge, a mediator, or your own attorney, the whole story should reconstruct itself from a single record instead of from scattered texts and a fading memory. That’s the same principle behind why the paper trail wins disputes: the record made at the time beats the one remembered afterward, every time.
This is also a problem you can largely prevent at signing. A lease with a clear occupancy clause, a defined guest limit, an add-occupant procedure, and a real anti-subletting provision gives you the footing every step above relies on. If yours is vague, the lease agreement clause guide covers exactly what those provisions should say.
The bottom line
An unauthorized occupant is the lease violation most likely to be mishandled, because the two failure modes pull in opposite directions: do nothing and a guest acquires tenant rights you can’t undo; do too much and you’ve committed an illegal self-help eviction. The safe path between them is deliberate and documented.
Classify what you have — guest, long-term occupant, or sublet. Document the occupancy before you raise it. Address it to your tenant in writing, citing the specific clause. Offer a genuine choice: add the person to the lease after screening, or have them leave by a deadline. Escalate through a notice to cure and then non-renewal or eviction only if they refuse both. Keep familial status and fair housing in mind, and let the lease and the conduct — not a headcount — do the work.
Handled that way, the extra car in the driveway stops being a problem you dread and becomes a routine, documented enforcement you can resolve in writing, with the record already on your side before the conversation starts.
