Cambridge’s Airbnb Policy and the Housing Equation: Are We Building More and Housing Less?

Figure 1. Registered and estimated unregistered short-term-rental units.   Based on city figures as of June 2026. The unregistered figure is an estimate and is not synonymous with illegal use.

Cambridge is not alone in confronting this question. As the European material behind this discussion reports, cities including Paris, Barcelona, and Venice have adopted differing restrictions on short-term rentals as residents faced rising housing costs and fewer homes available for year-round use. On September 9, 2026, the European Commission proposed an Affordable Housing Act after concluding that, in cities and popular tourist destinations, the use of housing for purposes other than primary residence can worsen housing availability and affordability. The proposal would give local authorities clearer legal grounds to restrict short-term rentals when they reduce the supply of housing available for long-term use, provided that restrictions are targeted, necessary, proportionate, and supported by evidence. The proposal is not a blanket ban on Airbnb; it is an effort to make cities measure housing utilization and act where commercial or high-frequency short-term rentals aggravate housing pressure. [4]
Cambridge currently has an estimated 635 active short-term rental listings.[1]
 
A newer City Manager’s report, dated June 22, 2026, offers an additional and troubling measure: Cambridge reported 216 registered short-term-rental units while estimating approximately 500 unregistered units—roughly 716 units in all. [5]

How many existing housing units are already unavailable to long-term residents because they function as Airbnb rentals, corporate apartments, executive housing, or other forms of temporary occupancy?

Industry data suggest that roughly 56 percent are entire-home rentals rather than spare bedrooms. That translates into approximately 350 to 400 housing units functioning as whole-home short-term rentals.

These figures describe listings or units that may be unavailable for long-term occupancy; they do not necessarily represent units permanently removed from the housing stock. Some may be rented short-term only during part of the year. The critical policy question is how many days these units are occupied by temporary visitors and whether they are realistically available to year-round residents.

Elizabeth Bisio has observed in a 6.9.26 email that “The development of Cambridge Crossing and Alewife has brought over 4,000 new residential rental units to market in 10 years. It still hasn't made the city any more affordable. What they don't tell you is that many of the new luxury apartments are filled with Airbnb and corporate short stays, so those units have little impact on long-term housing supply.” As she explains, “The MFZ plans to add the same number in 20 years, sacrificing what makes people even want to be in Cambridge in the first place to achieve that goal. The city has completely lost any ability to think critically on the housing issue.”

An architect and Neighborhood Nine condominium owner in her email response similarly questions whether Cambridge’s short-term rental regulations are being effectively enforced and whether the city is adequately tracking condominium-based short-term rentals. She asks “[W]hat happened to the 2025 short-term rental Zoning Ordinance amendments 4.60?” She also notes that condo associations objected strongly to the 2025 removal of the requirement for proof of condo association approval in order to register with ISD. Inspectional Services (ISD) admitted to City Council that it finds these units hard to track, and the City’s own estimate of approximately 500 unregistered units demonstrates the scale of the problem.   

If, as residents have reported, ISD is no longer proactively investigating whether an Airbnb listing is legitimate unless a complaint is filed, the City should say so plainly and explain what has replaced that function. The public record does not clearly establish that investigations have formally ended. It does show a system built around registration and resident complaints: the City’s current short-term-rental page directs residents to report specific properties through See Click Fix, while the City Manager’s 2026 report says ISD was working to make the registry more accessible and to make it easier for residents to file complaints. [5] [6]

That is not enough. Cambridge should hire a small, dedicated short-term-rental compliance team to canvas every neighborhood. Staff could look for publicly visible indicators of possible unregistered short-term rentals—lock boxes, posted entry instructions, repeated turnover of short-term occupants, or other signs of transient use—and compare those observations with the City’s registry. A lock box alone would not prove a violation; it would be a lead for lawful follow-up through notice, records requests, and inspection. The purpose would be to identify unregistered or ineligible rentals systematically, without trespassing or presuming that every visible sign represents a violation. Residents should not be expected to serve as the City’s unpaid enforcement department.

What are the broader impacts of this? A review of recent multifamily projects compiled by Councillor Zusy and city staff in a crowdsourced tracker reports 1,097 net-new units proposed (estimated), based on 117 properties with both original and proposed unit counts; 31 additional properties await proposed-unit data. Applying a transparent adjustment to the tracker—removing the 12 properties categorized as Commercial or Empty-lot/Vacant-lot—leaves 728 net-new units. That 728 figure is calculated from the tracker; it is not a separately reported tracker total and it includes mixed-use projects.The tracker covers active and potential redevelopments, not completed construction. Its totals should therefore be described as a redevelopment-pipeline estimate, while neighborhood impacts must be assessed project by project.

Figure 2. Multifamily housing units built or proposed.  . Source: Councillor Zusy’s crowd sourced Cambridge Redevelopment Tracker, accessed September 15, 2026. The tracker reports 1,097 net-new units across 117 properties with both original and proposed unit counts. The 728-unit comparison is calculated by excluding 12 properties categorized as Commercial or Empty-lot/Vacant-lot; it is not a separately reported tracker total.

​Residents are routinely told these tradeoffs are necessary because every housing unit matters.

But there is another side of the ledger. Cambridge currently has an estimated 635 active short-term rental listings. Industry data suggest roughly 56 percent are entire-home rentals, representing approximately 375 housing units. Add furnished corporate apartments, relocation housing, executive rentals, and similar temporary accommodations, and a reasonable estimate reaches roughly 575 units citywide, many of which do not add to the long-term housing supply, or add very few units to it.

The City’s newer estimate of approximately 716 short-term-rental units is not directly interchangeable with the 375-unit whole-home estimate or the broader 575-unit temporary-occupancy estimate. The sources count different things and use different methods. But the discrepancy itself is significant: Cambridge may have hundreds of units operating outside the ordinary long-term housing market, while the City lacks a reliable neighborhood-level count.

These numbers deserve attention. On the current tracker numbers, the 728-unit adjusted redevelopment estimate is about 153 units larger than the broader 575-unit temporary-occupancy estimate. That comparison is illustrative only: one figure is a redevelopment pipeline and the other is an estimate of temporary occupancy.

Figure 3. Approximate scale comparison.  These categories use different definitions and are shown for scale only; they are not additive or directly interchangeable.

The City’s later estimate of 216 registered units plus approximately 500 unregistered units is about 716 units—roughly 12 units below the tracker’s 728-unit adjusted redevelopment estimate. These figures should not be treated as an exact apples-to-apples comparison: one is an occupancy estimate and the other is a redevelopment-pipeline estimate. They do, however, show why Cambridge needs a dependable accounting of how many residential units are actually serving long-term residents.

Moreover, city officials have acknowledged that short-term rentals are difficult to track. With the City already estimating approximately 500 unregistered units, a total in the neighborhood of 700 to 750 short-term-rental units remains plausible. That range is broadly comparable to, rather than clearly greater than, the tracker’s 728-unit adjusted redevelopment estimate.

The distinction is especially important when discussing “units lost.” The 375-unit whole-home estimate and the broader 575-unit temporary-occupancy estimate should not be presented as proof that every unit is permanently unavailable to Cambridge renters. A more defensible measure would identify units that are whole-home, non-primary-residence, commercial, unauthorized, or intentionally vacant. Those are the units most clearly removed—or withheld—from the long-term housing market.

The point is not to eliminate every form of short-term or furnished housing. Cambridge has legitimate reasons to accommodate visiting scholars, fellows, researchers, medical professionals, and business travelers. Legal, registered short-term rentals may provide useful lodging, and properly regulated academic or institutional housing can serve an important public purpose. But that benefit should not be used to shield unauthorized commercial rentals or units deliberately withheld from the long-term market. Cambridge should count legal visitor-serving accommodations separately from unregistered whole-home rentals and from vacant or warehoused housing.

Where owners keep units vacant or use temporary occupancy to keep viable long-term renters out while waiting for appreciation, redevelopment, or a more profitable opportunity, this is effectively a form of land banking. In existing buildings, “housing warehousing” or “strategic vacancy” may be the more precise terms. Such units help neither visiting scholars nor long-term renters. Where this practice is occurring, the City should document it and include it in a public housing-utilization survey.

As 2019 City Council candidate and Mid-Cambridge Neighborhood Group President, John Pitkin notes (6.10.26) “housing is about places for people and families to live, 12 months a year….[not] just a place for someone to spend a night as long as it is not a commercial hotel or a group shelter.” He adds “a survey of housing occupancy and vacancy would provide a basis for designing better housing and zoning policies.”

All this raises an obvious question:

If hundreds of housing units are functioning outside the long-term residential market, should that reality play a larger role in housing policy?

The issue is not simply how many units Cambridge builds. It is also how many units remain available to long-term residents.

Many redevelopment projects involve demolition, reduced open space, tree loss, increased impervious surfaces, and larger building footprints.

Supporters argue these costs are justified because additional housing is desperately needed. Perhaps. But if the city is simultaneously allowing hundreds of units to function as temporary accommodations, the tradeoffs deserve closer scrutiny.

The current tracker estimates 162 inclusionary (IZ) units among 1,097 net-new units—about 15 percent—but its entries are estimates and the tracker does not establish when, or whether, every proposed project will be completed.

Among the 117 properties with both original and proposed unit counts, 16 show no net-new units (about 14 percent). Forty-two add 1–3 net-new units (about 36 percent); the narrower 2–3-unit group contains 20 properties (about 17 percent). The tracker’s size-of-change chart does not establish sale prices or that every project is a condominium.
​
 Cambridge’s housing debate has focused almost entirely on production. It should also focus on utilization. But more important questions are in play. How many units do we need? How many are being removed from the long-term market? Where should they be located? For whom? And what environmental costs accompany new development? Those questions deserve attention.

Before Cambridge asks neighborhoods to absorb ever more redevelopment, it should first establish a reliable, public accounting of how existing housing is being used. That means maintaining an accurate registry, investigating suspected violations, and funding a citywide canvass capable of identifying units that never appear in the official records.

Sources

[1] https://www.cambridgema.gov/-/media/files/cdd/zoningdevel/amendments/2025/shorttermrentals/zngamend_str_lawdeptletter_20250805.pdf?utm_source=chatgpt.com

[2] https://www.cambridgema.gov/-/media/files/cdd/zoningdevel/amendments/2025/shorttermrentals/cma2025176.pdf

[3] Councillor Zusy’s Office, Cambridge Redevelopment Tracker, current live summary and project list, accessed September 15, 2026: https://cambridge-redev-tracker.pages.dev/. The tracker reports 1,097 net-new units proposed (estimated) across 117 properties with proposed-unit figures; 31 properties await data.

[4] Reuters, “Airbnb set to face more curbs as EU proposes rules to tackle housing crunch,” September 9, 2026: Reuters report. See also the European Commission press release, “New EU rules to help local authorities tackle the housing crisis,” September 9, 2026.

[5] City of Cambridge, City Manager’s Agenda Item CMA 2026 #188, June 22, 2026: Short-Term Rental Ordinance recommendations and survey results.

[6] City of Cambridge, Register a Short-Term Rental, including the City’s public registry and complaint instructions.