Buying in Williamstown 2026: Underwrite the Cap, Not the Hype

Buying a short-term rental in Williamstown, Massachusetts in 2026 means underwriting two things at once: a real, unresolved disagreement between data vendors about what the property might earn, and a structural zoning change, adopted in May 2025, that did not exist a year earlier. Neither can be treated as a footnote. A buyer who prices only the revenue range without pricing in the 90-day cap is underwriting a business model the town no longer fully permits in residential districts.

This piece lays out both pieces honestly: the disputed revenue range across three vendors, and the zoning constraint that applies regardless of which revenue figure you believe. It closes with what a defensible Williamstown buyer packet should actually contain, not a pitch to skip the harder underwriting work.

None of this means Williamstown is a bad market to buy into. It means it's a market that requires more careful underwriting than a quick glance at a single vendor's headline number, precisely because that headline number changes meaningfully depending on which vendor produced it, and because the regulatory ground shifted under this market less than a year and a half before this piece was written. This is not legal advice.

The Revenue Range You're Actually Underwriting

Three vendors have recently pulled Williamstown short-term rental data, and they don't agree. AirROI, on an August 2025 to July 2026 window updated August 8, 2026, shows a typical $34,750 across 93 listings, 37.2 percent occupancy, a $399 average daily rate, and $140 in revenue per available room, with revenue down 6.0 percent year over year against 9.4 percent supply growth. AirDNA, refreshed September 1, 2026, shows roughly $36,900 across a much larger 195-listing sample, 51 percent occupancy, and a $232 average daily rate. Rabbu, pulled April 27, 2026, shows $47,379 across 49 listings, 31 percent occupancy, and a $369 average daily rate.

None of these three should be averaged into a single number for underwriting purposes; no vendor produced a blended figure, and manufacturing one creates a false precision this data doesn't support. The more defensible approach for a purchase decision is to run the pro forma against both ends of the range, not just the favorable one, and to weight the lower end more heavily given AirROI's negative year-over-year trend, the most complete trend data available on this pull. A buyer who underwrites only off Rabbu's $47,379 figure, the highest of the three and also the smallest sample at 49 listings, is underwriting off the least conservative and arguably least representative of the three available numbers.

A related figure worth naming, and never confusing with these three: Planning Board member Ken Kuttner's citation of roughly 168 short-term rentals operating in town as of May 2025. That is a broader operator estimate, not an Airbnb-active-only revenue sample, and it should never be blended into any of the three vendor figures above when sizing a purchase.

It's also worth stress-testing the purchase against a scenario where the -6.0 percent year-over-year revenue trend continues for another year rather than reversing. That's not the headline number to lead a buyer packet with, but a buyer who has already modeled that more conservative path, and confirmed the deal still pencils, or at least understood by how much it doesn't, is in a stronger position than one who only ran the numbers against a single optimistic year.

Entry Cost, and What This Research Cannot Supply

This research pass did not confirm a current median sale price or a set of recent comparable sales specifically for Williamstown, and this piece is not going to guess one or borrow a broader Berkshire County median as a stand-in for a town-specific figure. Pull current comparable sales directly from a local listing service or agent at draft, specific to Williamstown, before running an entry-cost calculation. A number borrowed from a countywide median or a neighboring town's comps risks materially misrepresenting what a Williamstown property actually costs to acquire.

Once you have a real entry cost, run it against both ends of the AirROI-to-Rabbu range, not just the number that makes the deal pencil most easily. If the purchase only makes sense at the high end of a disputed three-way range, that's useful information about how much margin for error the deal actually has, not a reason to quietly adopt the more favorable number as your working assumption.

It's also worth factoring in financing costs and any renovation or furnishing budget separately from the acquisition price itself, since a property that needs meaningful work before it can compete against listings that already have current, specific Williamstown-focused photos and copy is effectively a different underwriting case than a turnkey purchase. This piece doesn't estimate those costs, since they vary too widely by property condition to generalize, but they belong in the same packet as the entry cost and revenue range, not treated as a separate, later conversation.

The Zoning Cap Is Not a Footnote

Williamstown's Annual Town Meeting passed a 90-cumulative-day annual cap on short-term rental use of a dwelling unit in residential districts, RR1, RR2, RR3, and GR, on May 22, 2025, by a vote of 219 to 25. This is not legal advice, but the underwriting implication is direct: a buyer evaluating a property in one of these districts as a year-round short-term rental is evaluating a business model the town no longer fully allows going forward, regardless of how the property performed historically under any of the three vendor figures above.

Four narrow exemptions exist, covering owner-occupied bedroom rentals, certain accessory-dwelling-unit arrangements, and servicemember or Foreign Service owners under specific federal statutes; none function as a general workaround for a standard investment purchase. Nonresidential districts where dwellings are allowed carry no day cap under this bylaw, which makes confirming the specific zoning district of any property you're considering, not just its general location, a required step before running a purchase pro forma, not an optional one.

A property's historical AirROI, AirDNA, or Rabbu performance describes what it earned under conditions that, if it sits in a residential district and previously operated year-round, may no longer be fully legal. Build the 90-day cap into the pro forma directly, treating it as a structural limit on achievable revenue going forward, not background context to mention once and set aside.

What the Wrong Buyer Looks Like Here

The wrong buyer in this market is someone assuming a Williamstown property can run the same way a pre-2025 short-term rental did, without confirming the zoning district or the current day-count against the 90-day cap. It's also someone quoting Rabbu's $47,379 figure as settled fact in a purchase conversation without disclosing that AirROI and AirDNA both show meaningfully lower numbers on the same or a similar window. A seller's packet or listing agent that leans on the highest available figure without naming the range is not giving a buyer the full picture, and a buyer who doesn't ask for it is accepting an incomplete one.

It's worth asking a seller directly, before making an offer, what the property's actual historical short-term rental night count looked like, whether it exceeded 90 nights annually, and whether the seller has already confirmed the property's zoning district against the town's residential-district list. A seller who can't answer these questions clearly is not necessarily hiding something, but it does mean the buyer's own due diligence has more work to do before closing.

It's also worth being skeptical of any pitch that treats North Adams's or Great Barrington's numbers as evidence of what a Williamstown property could someday achieve. North Adams's AirROI figure, a typical $23,817 across 76 listings, is meaningfully lower than any of Williamstown's three vendor figures, and Great Barrington's roughly $42,830 figure describes a different market fifty miles south with its own guest base. Neither is a ceiling or a floor for what a specific Williamstown property will actually do, and a buyer packet that borrows either number to make a Williamstown deal look better is misrepresenting the property's own market.

Building a Defensible Buyer Packet

A clean underwriting packet for a Williamstown purchase should carry all three revenue figures, named and sourced individually, rather than a single confident number: AirROI's $34,750 on 93 listings, AirDNA's roughly $36,900 on 195 listings, and Rabbu's $47,379 on 49 listings, each with its window and pull date attached. It should show AirROI's year-over-year trend, revenue down 6.0 percent against 9.4 percent supply growth, as context for how the range is likely moving, not just where it currently sits. And it should state plainly, in its own dedicated section rather than a buried footnote, the property's zoning district and its standing relative to the 90-day cap in residential districts, adopted May 22, 2025.

It should also state clearly what this research could not confirm: a Williamstown-specific median sale price, a precise permit-fee figure, and the exact process the town uses to track a specific unit's day count against the cap. Flagging those as open items to confirm directly with the town or a local agent, rather than filling them with a plausible-sounding estimate, is what separates a packet built to survive a lender's or a partner's careful second look from one built only to look complete on a first pass.

A packet built this way won't read as impressively as one leaning on Rabbu's higher figure alone, and that's deliberate. It's meant to survive a second look from a lender, a partner, or your own future self revisiting the deal a year later, and a number that survives that kind of scrutiny is worth more than one that only works if nobody checks it closely. If financing is part of the plan, the same discipline carries directly into that conversation, and a lender is likely to ask many of these same questions before underwriting the loan itself.

Keep a one-page summary at the front of the packet stating the core facts plainly, without adjectives: the three revenue figures with sources and dates, the year-over-year trend, the property's zoning district, and its standing against the 90-day cap. A packet that leads with that summary, rather than burying it in narrative, respects the time of anyone reviewing it and signals that the underlying research has already been done carefully. A buyer who assembles a packet this way isn't guaranteed a better price or a faster closing, but they are entering the negotiation with a clearer, more defensible picture of what they're actually buying than a packet built on a single flattering number ever provides, and that clarity tends to matter most exactly when a deal gets contentious or a lender asks harder questions than expected.

Finally, note the comparison context honestly: Great Barrington's separate, roughly $42,830 AirROI figure and North Adams's lower $23,817 figure both exist in the same general county, and neither should be blended into a Williamstown-specific number. A packet that keeps these three towns on three clearly separate lines, alongside the honest AirROI-to-Rabbu range and the 90-day cap, is the version most likely to hold up once someone other than the buyer starts asking questions about it.

A Pre-Offer Verification Checklist

Before you write an offer on a Williamstown property with short-term rental income in mind, it's worth running through a short list of confirmations rather than trusting the listing agent's marketing packet at face value. This isn't a substitute for the fuller analysis above, just the condensed version to carry into a walkthrough or an offer conversation.

Confirm the zoning district first: RR1, RR2, RR3, and GR residential districts are subject to the 90-cumulative-day cap under Bylaw §70-6.3, and that cap doesn't disappear because a previous owner operated the property differently. Confirm whether the current owner qualifies for either the owner-occupancy or the servicemember/Foreign Service exemption, and don't assume either transfers automatically to a new buyer, since eligibility depends on your own occupancy pattern, not the seller's. Confirm which revenue figure the seller is citing, AirROI's $34,750, AirDNA's $36.9K, or Rabbu's $47,379, and ask directly if it's the seller's actual trailing performance or a market estimate pulled from one of these three disagreeing sources.

Finally, if anything about zoning eligibility or STR registration is unclear from the listing materials, the Community and Economic Development office at 31 North Street, Third Floor, (413) 597-8287, is the entity that can confirm it directly, not the listing agent and not this article. A buyer who verifies these four points before closing is in a materially stronger position than one who discovers a zoning restriction or an inflated revenue figure after the deed transfers.

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Frequently Asked Questions

What's the honest revenue range to underwrite a Williamstown purchase against?

A range, not a single number: AirROI's $34,750 across 93 listings, AirDNA's roughly $36,900 across 195 listings, and Rabbu's $47,379 across 49 listings. Weight the lower end more heavily given AirROI's negative year-over-year trend, and never average the three into a single blended figure no vendor actually produced.

Does the 90-day cap apply to every Williamstown property?

Only in residential districts, specifically RR1, RR2, RR3, and GR. Nonresidential districts where dwellings are allowed carry no day cap under the May 2025 bylaw. Confirm the specific zoning district of any property you're considering directly with the town before assuming which rule applies.

Can a property continue operating as a year-round short-term rental after the cap?

Not legally, if it sits in an affected residential district and doesn't qualify for one of four narrow exemptions covering owner-occupied arrangements or servicemember and Foreign Service owners. Confirm your specific situation directly with the town before underwriting a year-round operating assumption.

Where can I find a current median sale price for Williamstown?

This research pass did not confirm one, and this piece deliberately doesn't guess a figure or borrow a broader Berkshire County median as a substitute. Pull current comparable sales directly from a local listing service or real estate agent specific to Williamstown before running an entry-cost calculation.

Is the 168 short-term rentals figure useful for sizing a purchase?

Not directly. That figure, cited by a Planning Board member in May 2025, is a broader estimate of the town's total operator base, not an Airbnb-active-only revenue sample. It should never be blended into AirROI's, AirDNA's, or Rabbu's listing counts when sizing a specific purchase decision.

Should I trust a seller's revenue figure if it doesn't match any of the three vendor pulls?

Ask directly which source and window it's drawn from. A property-specific historical figure can be legitimate if it reflects that unit's actual performance, but it should be reconciled against the town's broader data rather than presented as interchangeable with a market-wide estimate, and it still needs to be read against the 90-day cap going forward.

What should I ask a seller before making an offer?

Ask for the property's actual historical short-term rental night count, whether it has exceeded 90 nights annually, and whether the zoning district has been confirmed against the town's residential-district list. A seller who can't answer clearly doesn't necessarily indicate a problem, but it means your own due diligence has more to confirm before closing.

How should the 90-day cap change my purchase price expectations?

It should be built directly into the pro forma as a structural limit on achievable annual revenue for a residential-district property, not treated as background context. A property priced as if it could still operate year-round is being overvalued relative to what current zoning actually permits.

Is Great Barrington's revenue figure a useful stand-in if I can't get Williamstown-specific comps?

No. Great Barrington sits roughly fifty miles south with its own AirROI figure, about $42,830 across 166 listings, describing a different market with a different guest base and a separate zoning desk. It should never substitute for Williamstown-specific revenue or sale-price data in a purchase decision.

What's the single biggest underwriting mistake a Williamstown buyer can make?

Pricing the purchase off the highest available revenue figure, Rabbu's $47,379, without disclosing or weighing the lower AirROI and AirDNA numbers, and without building the 90-day residential cap into the pro forma as a real constraint on future operations rather than historical background.

Work with Crest & Cove Creative

A Williamstown purchase in 2026 means underwriting a disputed revenue range and a brand-new 90-day cap at the same time. Neither one is optional to price in.

Before you close on a Williamstown property, let's build the listing positioning around what the town's actual guest and its actual zoning limit can support, not a borrowed number. Name the failure mode the guest can check on the listing.

Reach out at crestcove.co or (256) 998-7502.