Why Airbnb Income No Longer Pencils in Cambridge or Boston

A buyer sent me a pro forma last month for a two-family near Inman Square in Cambridge. Good building, fair price, and the numbers worked. They worked because one line near the bottom assumed the top-floor unit would run on Airbnb and clear well above what a normal lease would bring. I did the thing I find myself doing more and more often now. I crossed that line out.

Not because the building was a bad buy. Because that line is a bet, and the odds on it just changed. For years the pitch on Cambridge, Somerville, and East Boston triple-deckers and condos was the same one. Buy the building, put one unit on a 12-month lease, run the other as a short-term rental, and let the nightly income carry a mortgage that a normal rent never could. It was a real strategy. For a long stretch the enforcement behind the rules was thin enough that plenty of people ran it in units the city never approved and never heard a word.

That window is closing, and in Cambridge it is closing fast. My take is blunt. If a Cambridge or Boston deal only works because of Airbnb income, it does not work. Model it on a standard 12-month lease, and treat short-term rental income as upside you may not be allowed to collect, not as the plan you underwrite the purchase on.

What Cambridge just did

On June 23, 2026, the Cambridge City Council accepted a new short-term rental petition and unanimously passed it to a second reading in the Ordinance Committee. On August 5, the Planning Board voted a unanimous positive recommendation. As of this writing it is not law yet. It is close, and the direction is not subtle.

The interesting part is where the new rules aim. Cambridge already limits short-term rentals to owner-occupied units, but the loophole has always been the platform. A host could ignore the city, list anyway, and the booking site happily collected its fee on a rental the city never registered. The new measure goes straight at that. Booking companies themselves would have to register with Cambridge, and they would face fines of $300 per day, per violation, for earning fees on unregistered listings, per Cambridge Day’s reporting on the June 23 vote. The proposal also adds a new “autonomous unit” category and floats a 90-day annual cap on certain whole-unit rentals, which city officials described at the August meeting as a placeholder still being negotiated.

Why go after the platforms? Because that is where the leverage is, and the compliance gap is enormous. City data presented at the August 5 Planning Board meeting pegged Cambridge at roughly 716 short-term rental units, of which only 216 were registered. That leaves about 500 operating illegally, so less than a third of the city’s short-term rentals are actually in compliance.

Cambridge short-term rentals: registered vs unregistered

Of roughly 716 estimated units, only 216 are registered with the city.

216 registered

~500 unregistered

~30% in compliance
~70% operating illegally

Put those together and the message to a buyer is clear. The strategy a lot of pro formas still assume, a whole unit humming along on Airbnb, is already illegal for most of the people doing it, and the city is now building a way to make the platform enforce the rule the host has been ignoring.

Boston already ran this experiment

If you want to know how this ends, look at Boston, which put the same idea in place years ago and has the receipts. Boston’s short-term rental ordinance was filed in June 2018 and took effect January 1, 2019. It allows short-term rentals only in owner-occupied condos and one-to-three-family homes, and it sorts them into three registration categories, all tied to the owner living there: a Limited Share of a bedroom in your primary residence at $25 a year, a Home Share of your whole primary residence at $200 a year, and an Owner-Adjacent unit in a two or three-family you own and occupy at $200 a year, per the city’s Inspectional Services page. Investor units and anything in a building of five or more units are out.

The teeth are in the platform rules. Boston requires booking agents to file monthly listing reports and to drop any listing without a valid registration number, or lose the right to operate in the city, under sections 9-14.10 and 9-14.11 of the ordinance. Airbnb sued, then settled in August 2019 and agreed to a December 1, 2019 delisting deadline, per WBUR. Flagged listings now come down within a few business days.

The result was not subtle. A Boston University Initiative on Cities brief found that the rules cut Boston short-term rental listings by about 56% on average, with roughly 3,000 listings removed between the 2018 vote and the start of the pandemic.

What enforcement did to Boston’s listings

Short-term rental listings, before the rules vs after platform enforcement.

Before the ordinance (2018)

Baseline listings

After enforcement (by early 2020)

~44% remain

~56%

Average drop in short-term rental listings

~3,000

Listings removed, 2018 to early 2020

So the “automated enforcement just went live” framing you may have seen is only half right. Boston’s platform cross-checking has been running since 2019. That is precisely why the listings already fell by more than half. What is new in 2026 is that the tooling keeps getting sharper, and that Cambridge is now copying the part of Boston’s playbook that actually worked, pointing it at the one party with a kill switch.

The rule that quietly kills the investor thesis

Here is the part that matters most for anyone buying to rent short-term, and it is not new or pending. It is already the law in all three cities. A whole-unit short-term rental is legal only in the operator’s own primary residence, or in a narrow owner-adjacent case where you live in the building and own every unit in it. There is no version of these rules where you buy a unit purely as an investment, never live there, and run it on Airbnb legally.

That single requirement turns the whole strategy from an investor play into a house hack. You have to live in the building. Cambridge allows an operator-occupied rental of up to three bedrooms in your primary residence, or an owner-adjacent whole unit if you own all the units in a building of four or fewer, per the city’s registration guidance. Somerville is even tighter. Its ordinance requires the unit to be the operator’s primary residence and offers no owner-adjacent option at all, so you cannot run the second unit of your two-family short-term even if you live next door.

	Cambridge	Boston	Somerville
Investor whole-unit STR	Not allowed	Not allowed	Not allowed
Who can operate	Operator-occupied, or owner-adjacent in a building of 4 units or fewer	Owner-occupied only, in 1 to 3-family or condo	Operator’s primary residence only, no owner-adjacent
Registration cost	$500, plus an inspection	$25 to $200 a year by category	$250
Platform enforcement	Proposed: platforms fined $300/day per unregistered listing	In force since 2019: monthly reports, delisting	Booking-agent liability once notified

I want to be fair here. A house hack is a genuinely good way to get into an expensive market, and I help clients do it. But it is a very different thing from what most Airbnb pro formas describe. If your plan requires you to live in the building, that is a lifestyle decision as much as an investment, and it caps how much of the property can ever produce nightly income.

Run the actual numbers on a Cambridge unit

Set the legal problem aside for a second and just run the math, because even in the best case the premium is thinner than people expect. The average Cambridge short-term rental grossed about $36,383 over the year ending March 2026, at 52% occupancy and a $239 nightly rate, across 738 tracked listings, according to AirROI. Now compare that to a plain 12-month lease. A Cambridge one-bedroom runs around $3,100 a month, and a two-bedroom around $4,000, based on 2026 data from RentCafe and Zumper. That is roughly $37,200 a year for the one-bedroom and $48,000 for the two-bedroom.

Read that again. The average short-term rental grosses about what a one-bedroom brings on an annual lease, and less than a two-bedroom. And that Airbnb figure is gross, before a single cost.

	Short-term rental (average Cambridge unit)	Standard 12-month lease
Gross annual income	~$36,383	~$37,200 (1BR) to ~$48,000 (2BR)
Who pays utilities	You do	The tenant
Furnishing and setup	$10,000 to $20,000 up front	None
Cleaning and turnover	Every stay	Roughly once a year
Management	20% to 30% if hired out	8% to 10%, or self-managed
Taxes and registration	14%+ occupancy tax, $500 registration, $1M insurance	Standard landlord insurance
Legal status for an investor	Not allowed unless you live there	Allowed

A sharp operator with a prime whole unit can beat the average, no question. But the average is the honest starting point, and the average says the premium is thin once you net out the work and the risk. To justify buying on the Airbnb line, you have to assume top-decile performance, in a category that is illegal for investors, in a city about to fine the platform that carries your listing. That is a lot of assumptions stacked on one number.

The tax and insurance stack most pro formas skip

The occupancy tax alone surprises people, because a long-term lease has nothing like it. Massachusetts extended its room occupancy excise to short-term rentals in 2019 under Chapter 337 of the Acts of 2018. On top of the state rate sit a local option and, in Cambridge and Boston, a convention center fee, so the tax on each stay lands well above 14%. You collect it and remit it, but it makes your nightly price less competitive, and it is one more filing you own.

The short-term rental cost stack a lease does not carry

5.7%

State room occupancy excise

up to 6%

Local option (6.5% in Boston)

2.75%

Convention center fee (Cambridge & Boston)

$1,000,000

Liability insurance required per unit

Even if the city says yes, your condo docs may say no

There is a second gate that has nothing to do with City Hall, and buyers miss it constantly. If you are looking at a condo, the association’s own rules can ban short-term rentals outright, even where the city would let you run a home share. This is not rare, and it has been getting more common as boards react to transient guests in their buildings.

Massachusetts condo associations can restrict or ban rentals when a supermajority of owners, usually at least 67% of the beneficial interest, votes to amend the master deed or bylaws, according to the condo attorneys at Marcus, Errico, Emmer and Brooks. Those restrictions hold up. Massachusetts courts have enforced condominium restrictions for decades, going back to the SJC’s 1983 decision in Franklin v. Spadafora, and the common tools today are a minimum lease term, often one year, a cap on the share of units that can be rented, and an owner-occupancy requirement. A one-year minimum lease term is the quiet killer, because it makes any nightly rental a violation of your own building’s rules regardless of what the city allows.

So before you write an offer on a condo you plan to rent short-term, read the master deed, the bylaws, and the current rules. Not the listing sheet, the actual recorded documents. I dig into this kind of thing with clients all the time, and it is a regular theme in my condo-living writing. A five-minute read of the docs can save you from buying a plan your own association already outlawed.

If you are selling on “strong Airbnb income”

This cuts the other way too. If you are marketing a two-family or condo on its short-term rental history, a booking screenshot is not proof of anything a buyer can rely on. Sophisticated buyers, and every buyer’s attorney worth hiring, are going to ask one question. Is this unit registered and compliant, and can the buyer legally keep running it? For an investor buyer who will not live there, the honest answer in Cambridge, Boston, and Somerville is usually no.

That has real consequences for price. A lender is not going to underwrite non-conforming short-term rental income, so it does not help the buyer qualify, and a good attorney will flag the whole line during the review. The number that felt like a selling point can quietly become a liability that invites a lower offer. If you want that income to count, show current city registration and compliance, and price the property on the use a buyer can actually and legally continue. If you want a straight read on what your building is worth on its real, defensible income, that is exactly the kind of question our home value tool and a quick conversation are built for.

Where short-term rental income still makes sense

I am not anti-Airbnb. I am anti-guessing with six figures on the line. Short-term rental income still works in two honest forms. The first is a true owner-occupied house hack. You live in the building, you run a home share or an owner-adjacent unit inside the rules, you register, and you treat the nightly income as a real but capped supplement to your own housing cost. That is legal, and in a market this expensive it can be the difference that gets someone into a building at all.

The second is to stop trying to force the short-term model and build long-term income the state actually wants you to build. A legal accessory dwelling unit, now allowed by right in much of Massachusetts, produces steady 12-month rent with none of the registration, tax, or delisting risk. I walked through that whole path in our Massachusetts ADU guide, and for most buyers it is a far more durable way to make a two-family or a big single-family pay. If you want to think through the investment math on any of this, it is the heart of my investment-property writing.

How I would underwrite one of these today

When a client brings me a building where short-term income is part of the story, we run the same short checklist before we get anywhere near an offer.

The five-minute short-term rental gut check

1. Pull the unit’s status on the city registry, and confirm what is actually registered versus what the listing claims.
2. Confirm which legal category, if any, you could operate under, and whether it requires you to live in the building.
3. Read the master deed, bylaws, and rules for any minimum lease term or leasing cap.
4. Model the property on a standard 12-month lease. If it does not work on the lease, it does not work.
5. Treat any short-term rental income as upside, and size it off the average unit, not the best month a seller ever had.

Run that, and the Airbnb line stops being a leap of faith and becomes what it should be. A bonus, if you can legally collect it, on a deal that already stands on its own. If the whole thesis lives or dies on nightly income in Cambridge, Somerville, or East Boston right now, my advice is the same as it was to that buyer near Inman Square. Take a hard look before you sign, because a five-day delisting or a per-day fine erases the premium a lot faster than it took to build.

If you are weighing a multifamily or condo where short-term income is part of the pitch, on either side of the deal, that is exactly the kind of thing we work through with clients every week. You can start with the home value tool or just reach out. I would rather give you the straight version now than watch a pro forma talk you into the wrong building.

Sources

• Cambridge Day, “City Council tries to ground AirBNB, rental algorithms,” June 25, 2026 (June 23 vote, $300/day platform penalty).
• Cambridge Day, short-term rental regulation update, August 5, 2026 (Planning Board recommendation, 716 units / 216 registered, autonomous-unit category, 90-day cap).
• City of Cambridge, register a short-term rental (operator-occupied and owner-adjacent categories).
• Cambridge Inspectional Services, short-term rental guide ($500 fee, inspection, $300/day penalty).
• City of Boston Inspectional Services, short-term rentals (three categories, owner-occupancy).
• City of Boston, short-term rental ordinance (platform data sharing, delisting, effective January 1, 2019).
• WBUR, Airbnb and Boston settlement, August 29, 2019 (December 1, 2019 delisting deadline).
• Boston University Initiative on Cities, “Short-Term Rentals in Boston: Regulation, Compliance, and Impact” (about 56% drop, roughly 3,000 listings removed).
• City of Somerville, short-term rentals (primary residence, $250, no owner-adjacent option).
• Massachusetts DOR, TIR 19-3, room occupancy excise on short-term rentals (Chapter 337 of the Acts of 2018, $1M insurance).
• Mass.gov, local option excise taxes (local option up to 6%, 6.5% Boston, convention center fee, community impact fee).
• Marcus, Errico, Emmer and Brooks, restricting condominium rentals (67% supermajority amendment, Franklin v. Spadafora).
• Moriarty Troyer and Malloy, short-term rentals and Massachusetts condo boards.
• AirROI, Cambridge, Massachusetts short-term rental market data, 2026 (average revenue, occupancy, registration share).
• RentCafe and Zumper, Cambridge, Massachusetts average rent data, 2026.