Renting out rooms in a Boston apartment can require a Massachusetts lodging house license once you cross a specific threshold. If you're subletting one spare room, you are almost certainly nowhere near this. Massachusetts draws its line at four. Below that, you're a tenant with roommates. At or above it, you may be operating something the state licenses, and doing that without a license is unlawful.
The complication, and the reason this article exists, is that Chapter 140 is clear about the number and never defines who it applies to. There is an answer, but it sits in a different statute and a legal aid guide rather than in the law everyone reads. Most people subletting rooms in Boston never find out which side they're on until someone asks.
What the law actually says
Massachusetts General Laws Chapter 140, Section 22 defines a lodging house as:
"A house where lodgings are let to four or more persons not within second degree of kindred to the person conducting it."
The section explicitly includes fraternity houses and dormitories of educational institutions. It explicitly excludes dormitories of charitable or philanthropic institutions, convalescent homes, nursing homes and rest homes licensed under Chapter 111, and group residences licensed or regulated by agencies of the Commonwealth.
Two things follow from that sentence, and they are the parts you can rely on.
The threshold is four. A license question arises when four or more people who aren't close relatives of whoever is running it hold lodgings in one building. Below four, the definition doesn't reach you.
It applies to rooms, not households. The distinction is between lodgings, where someone has exclusive use of their room and shares the kitchen and bathroom, and a group of people who jointly rent a whole place together. As MassLandlords sets out in its guide to lodging houses, the license question turns on four or more unrelated individuals renting spaces with shared cooking, eating, living, sleeping or sanitary facilities in the same building. And it is unlawful to run a lodging house in Massachusetts without being properly licensed. Chapter 140, Section 24 sets the penalty at a fine of $100 to $500, up to three months in jail, or both.
Where the line is, and who it applies to
The part that is settled
The number. Four or more people, not closely related to the person running it, holding lodgings in one building. That's the statutory trigger, and it isn't ambiguous.
The part Chapter 140 leaves out
Who counts as "the person conducting it."
Chapter 140 uses that phrase and never defines it, which is why people assume the question is open for tenants. It isn't. If you hold a lease and sublet four or more rooms within it, you can be the person conducting a lodging house.
Two sources settle it. Massachusetts General Laws Chapter 111, Section 199B defines a rooming house as one where space is "let or sublet for compensation by the owner or operator," language that plainly reaches a tenant who sublets. And MassLegalHelp's Legal Tactics: Tenants' Rights in Massachusetts states that the person conducting a rooming house "could be the landlord (or owner), the manager of the dwelling, or could be a primary tenant who sublets rooms to 4 or more unrelated people," citing Hall v. Zoning Board of Appeals of Edgartown, 28 Mass. App. Ct. 249 (1990).
Renting instead of owning doesn't move you outside that definition. What the statute can't settle is whether your particular setup is lodgings to begin with.
So the picture looks like this.
| Your situation | Where you stand | What to do |
|---|---|---|
| You sublet one or two rooms, and everyone shares the whole home | Below the statutory threshold either way | Check your lease permits subletting. Nothing else here applies to you |
| You sublet three rooms, with shared kitchen and bathroom | Below the threshold at three, but one more room crosses it | Count who actually holds lodgings before you add anyone else. Four is the trigger whether you own or rent |
| You sublet four or more rooms to unrelated people | At or over the line as written | Do not proceed on an assumption. Get advice before you continue |
If you're in the middle row, you are in the normal case. Most people subletting rooms in a Boston apartment are, and the margin between three and four is a single roommate, which is why it's worth counting carefully rather than assuming.
Check your lease before any of this matters
For most tenants, a lease's subletting clause is the obstacle that arrives first.
Most Boston leases restrict or prohibit subletting without the landlord's written consent. If yours does, subletting a room without permission can put you in breach regardless of how many people are involved and regardless of whether any license question arises.
That is a faster and more likely problem than a licensing one, and it is entirely within your control to check. Read the subletting clause, and if it requires consent, get it in writing before you list anything.
Our guide to subletting rules in Boston covers what those clauses usually say and what landlords typically require.
Who can actually answer this
Three places can tell you whether your arrangement needs a license: the Boston Licensing Board, Inspectional Services, and a housing attorney or legal aid service. This section sits near the top rather than at the end because for a lot of readers it is the answer rather than a footnote.
Nobody writing a general guide can tell you whether your specific arrangement is a lodging house. It depends on how many people, what they have exclusive use of, what's shared, whether you own or rent, and what your municipality does with the state definition. Those are facts an article can't see.
What each one is for:
The Boston Licensing Board administers lodging house licenses in the city and is the authority on whether your situation needs one. Asking is free, and asking before you start is considerably cheaper than being asked afterward.
Inspectional Services handles the property-condition side and is the right call for questions about what standards would apply.
A housing attorney or a legal aid service. If you already have people in the rooms, or if there's money at stake, this is worth an hour of someone's time. Massachusetts legal aid organizations handle housing questions and are the right route if cost is a barrier.
Ask before you advertise. The order matters: a licensing question answered in advance is a form to fill out, and the same question answered after a complaint is a different conversation.
If you're already renting rooms out
Don't panic, and don't assume the worst. Work through it in order.
- Count accurately. How many people hold lodgings, and are any of them related to you within the second degree? The threshold is specific.
- Establish what's shared and what's exclusive. A group who jointly rent a whole apartment together and share all of it are in a different position from four people who each rent a room and share a kitchen. That distinction is the one the definition turns on.
- Check the lease question separately. It's independent of licensing and often more urgent.
- Then ask. With those three facts in hand, the Licensing Board conversation is short and specific.
What you should not do is keep going on the assumption that nobody will ask. Operating an unlicensed lodging house is unlawful in Massachusetts, and that exposure sits with the person conducting it — which, if you are the one collecting rent for the rooms, may well be you.
Screening people lawfully
The lawful method is a written screening process applied identically to every applicant. There's a right answer here and a common wrong one.
Fair Housing law applies to you when you're the one renting out the room. That is true even though you live there, even though it's your home, and even though the stakes feel personal. You cannot select on race, color, national origin, religion, sex, familial status, disability, or the additional characteristics Massachusetts protects.
The wrong turn is almost always well-intentioned. It usually shows up as wanting whoever moves in to feel safe about the decision, which is a completely reasonable instinct and also exactly the framing under which people start filtering on characteristics they aren't allowed to filter on. Feeling unsafe about a category of person is not a lawful screening criterion.
What is lawful is a consistent process applied to everyone: the same questions, the same verification of ability to pay, the same reference checks, the same criteria in the same order. Write your criteria down before you start, and apply them identically. A written screener sent to every inquirer is both fairer and easier to defend than a series of judgment calls.
If you want the other side of this, our guide on how to vet a roommate before signing a Boston lease covers what the person answering your ad is weighing about you.
Frequently asked questions
How many people can I rent rooms to before I need a license?
The statutory definition is triggered at four or more people holding lodgings who aren't within the second degree of kindred to the person conducting it. Below four, the definition doesn't reach you.
Does it count if I'm a tenant rather than the owner?
Yes, it can. A primary tenant who sublets rooms to four or more unrelated people can be "the person conducting" a lodging house. Chapter 111, Section 199B covers space that is let or sublet by the owner or operator, and MassLegalHelp's tenants' rights guide names a primary tenant who sublets among the people who can be conducting one. Holding a lease rather than a deed does not put you outside the definition.
Are my roommates lodgers?
Not necessarily. Sharing a whole apartment jointly is a different arrangement from each person renting a room with exclusive use and shared facilities. Which one you have is a matter of how the tenancy is actually structured.
What if my lease doesn't mention subletting?
Ask your landlord in writing anyway. Silence in a lease is not the same as permission, and a written answer protects you either way.
Is it illegal to run a lodging house without a license?
Yes. Massachusetts requires lodging houses to be licensed, and operating one without a license is unlawful.
Do I need a license if the rooms are in a house I own rather than rent?
The same statutory definition applies. Ownership removes the lease question, not the licensing one.
Can I just not tell anyone?
The exposure for operating unlicensed sits with the person conducting it. Asking in advance is materially cheaper than being asked later.
Sources, and when this was current
Written August 2026.
The definition of a lodging house is quoted from Massachusetts General Laws Chapter 140, Section 22. The four-or-more threshold and the shared-facilities test are from MassLandlords' guide to lodging and rooming houses.
The penalty for operating without a license is set by Chapter 140, Section 24: a fine of $100 to $500, up to three months' imprisonment, or both.
On who counts as "the person conducting it": Chapter 140 doesn't define the phrase, but Chapter 111, Section 199B covers space let or sublet by the owner or operator, and MassLegalHelp's Legal Tactics: Tenants' Rights in Massachusetts states that a primary tenant who sublets rooms to four or more unrelated people can be the person conducting a rooming house, citing Hall v. Zoning Board of Appeals of Edgartown, 28 Mass. App. Ct. 249 (1990).
What a guide still can't tell you is whether your particular arrangement is lodgings at all: whether each person has exclusive use of a room with shared facilities, or whether you jointly rent the whole place together. That turns on how your tenancy is actually structured, which is a fact an article can't see. If your arrangement is anywhere near the threshold, the Boston Licensing Board is the place to resolve it.
Licensing rules and municipal practice change. Check the current position before relying on anything here.
This article is informational and isn't legal advice.