RMR Group is not a housing nonprofit. It is a landlord. In the middle of July it looked at a roughly 97,000 square foot office building it owns at 7-9 Galen Street in Watertown, a building it mostly cannot fill, and filed plans to tear most of it down and rebuild it as 285 apartments.
That is the real housing story of 2026, and it fits inside one filing. No new task force. No ribbon cutting. A company with an empty building ran the numbers and decided that homes pay and offices do not.
I want buyers watching this one, especially the people who have been outbid in Newton, priced out of Cambridge, or told that Brookline was a reach. The pressure valve for those markets is not going to come from a new tower downtown. It is going to come from a handful of tired commercial buildings in the inner suburbs getting a second life as housing. Watertown is where it starts, and the reason it is starting now has almost nothing to do with a zoning law.
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The filing, in plain numbers
Here is what RMR actually put in front of the town. The existing building at 7-9 Galen Street is about 97,268 square feet of office and old mill space on a 2.84 acre site near Watertown Square, a short walk from the Charles. The proposal replaces it with roughly 247,900 square feet of new construction: 285 residential units and 6,000 square feet of ground-floor retail. The surface parking lot goes away, the existing garage stays, and the older street facades are kept and worked into the new building.
Two things are worth being precise about. First, this is a pre-application, filed in mid-July and first reported by Banker & Tradesman and Bisnow around July 14. The formal special permit application is expected later this summer, so the unit count and the square footage can still move. Second, this is not a quiet repaint of an old office. It nearly triples the floor area. Watertown will run it through special permit and site plan review at the Planning Board, because the parcel sits in the Watertown Square mixed-use overlay and is not a by-right site, plus a demolition review at the Historical Commission for a building more than 50 years old. None of that is a formality, and none of it is guaranteed.
Why an office landlord suddenly wants to build housing
RMR is not doing this out of civic feeling. It is doing it because the math on commercial space has broken. An empty building is a bill the owner pays every month in taxes, insurance, and debt, and right now a lot of Greater Boston commercial space is empty with no tenant in sight. The clearest place to see it is the lab market, the same life-science boom that was supposed to never stop.
Under 5% of the region’s lab space sat empty at the end of 2021. Newmark’s first quarter 2026 report puts lab vacancy near 36%. That is not a soft patch. That is years of pandemic-era construction landing into a market that stopped leasing. Offices are healthier than labs, but not by enough to change the logic. When a building cannot earn its keep in its current use, the owner has two real options, sit and bleed or convert it to something people still want. In 2026, the thing people still want is housing, and housing per square foot in a walkable spot near the Charles pencils better than lab space nobody is renting.
This is not the conversion law everyone wrote about
I wrote earlier this year about the state finally handing every town a way to turn commercial buildings into homes. It is worth being clear that what is happening on Galen Street is a different animal.
The legislative path is real, and I went through it in detail in the piece on the new commercial conversion zoning. In short, the state created a local option under Chapter 40A that a town can adopt to allow office-to-residential conversions by right, and, separately, the 2024 Affordable Homes Act set up a Commercial Conversion Tax Credit worth up to 10% of eligible project cost. Both are useful. Both are also permission slips and subsidies that assume someone already wants to build. The tax credit even requires that local zoning allow the conversion before a single dollar shows up.
RMR is not waiting for any of that. It is walking into Watertown’s ordinary permitting process with a private proposal because the economics already point that way. That is the whole point. The market is doing the conversion the Legislature spent two years trying to encourage. When capital moves on its own, ahead of the incentives, the shift is real and not policy-driven.
Porter Square shows the other half of the trade
If you want proof that this is the market talking and not a one-off, look a few miles east to 815 Somerville Avenue, on the Cambridge side of Porter Square in the old Lesley University campus. Back in February 2024, KS Partners won a special permit to convert offices there into labs. That was the trade everyone wanted to make two years ago, turning tired offices into high-rent lab space.
In March 2026, KS Partners went back to Cambridge and asked for two more years, writing that the project had stalled because of “the sharp contraction in leasing activity and capital markets within the Cambridge laboratory sector.” Their letter says they are weighing whether to build the approved lab or “a modified approach that best supports market demand.”
Read those two moves together. Two years ago, smart money turned offices into labs. Now smart money is buying time to walk away from a lab it already had permission to build. When a developer asks for an extension instead of breaking ground, the old use is dead and everyone in the room knows it. KS has not said the word apartments, and I am not going to put it in their mouth. But a rezoning in that corridor would allow housing by right, and it does not take much to see where a stalled lab site in a walkable square ends up.
Why a few hundred units matters more in Watertown
Watertown is about four square miles and 35,000 people, wedged between Cambridge, Newton, and Belmont. It has had almost no room to add housing, and it trades like it.
Homes here go fast and usually draw more than one offer. Condos have been closing in the low $800s. At any given moment there are only a handful of two-to-four-family listings on the market in the entire town. That is a supply-starved market by any measure, and it is exactly why prices have held up here even as the clock has slowed in pricier towns nearby.
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Drop 285 units into a market that size and it lands hard. The same 285 apartments in Boston proper, set against the 10,000 units planned out at Suffolk Downs, disappear into the noise. In Watertown they are a real fraction of everything that changes hands in a year. That is the difference between a supply story in the city and a supply story in a small inner suburb. The inner-suburb version is the one buyers should care about, because it happens in the towns they can still reach.
Watertown’s would be the biggest by unit count
This is not one strange filing. It is part of a wave, and Watertown’s is the largest of the group by units.
Synergy is converting the former Fallon Health headquarters at 10 Chestnut Street in Worcester into 198 apartments, a project MassDevelopment called the largest office-to-residential conversion in Massachusetts to date when the financing closed in the spring. The same firm won approval for 255 units at 280-300 Washington Street in Downtown Crossing, which the city billed as the largest conversion its board has approved. RMR’s 285 units on Galen Street would top both. It is early, so I would call it the largest proposed rather than a record. But three of the biggest commercial-to-residential projects in the state landing inside about a year is not a coincidence. It is capital running the same math in three different cities.
What this does for a buyer priced out of Cambridge or Newton
Let me be straight about what this does and does not do, because the honest version is more useful than the hopeful one.
It will not lower the price of a single-family house in Newton. These are rental units, not for sale, and the first lease is probably more than two years out. If you are waiting for a Watertown conversion to crack the Newton market open, you are going to wait a long time.
What it does do is add a few hundred homes in a walkable spot near Watertown Square and the Cambridge line, in a town that is a genuine alternative to Cambridge and Newton at a lower entry point. More rental supply in a starved market takes some pressure off rents and gives people a foothold close in without paying Cambridge prices. There is a small irony worth noting. RMR is a Newton company, and the housing it is proposing may end up serving the exact buyers Newton itself keeps pricing out. If you are renting to stay close to a Cambridge job, this is the kind of supply that helps you, even if it takes a couple of years to show up.
If you own near Galen Street
For owners and small investors the picture is more mixed, and worth thinking through before you react to a headline.
In the near term, a project this size means years of construction next door. In the medium term, 285 new households plus 6,000 square feet of retail is real foot traffic for the restaurants and shops around Watertown Square, and that kind of daily activity tends to support values in a walkable node. If you own a two-family and rent it out, more rental supply coming online can soften what you are able to charge once it leases, so underwrite that into your numbers instead of assuming today’s rent holds forever. The answer always depends on the specific building and block, not the headline. If you want the longer version of how I think about repositioning and rents, I keep it in the investment property writing.
What I am watching next
The real clock is the permit calendar, not the press release. The special permit and site plan review at the Planning Board is where the unit count gets negotiated, and the Historical Commission’s demolition review of a building with facades worth keeping can reshape or slow the whole thing. Any of those steps can change the number 285 or stop it cold. This is a signal of where capital wants to go, not a finished building.
The bigger thing I am watching is whether anyone follows. One tired office converting is a deal. A second and third filing in Watertown, Belmont, or Waltham is a pattern, and a pattern is what actually moves comps and rents. The lab and office glut is not clearing anytime soon, so more inner-suburb owners are going to run the same math RMR just ran. When they do, the supply finally starts showing up in the towns where buyers have been stuck.
If you are weighing Watertown against Cambridge or Newton, or you own a building and want to know what it is worth as it stands versus repositioned, that is exactly the kind of question we work through with clients every week. You can start with our home value tool or just reach out. I would rather give you a straight read now than watch you guess.
Sources
- Banker & Tradesman, “248K SF Commercial-to-Housing Project Proposed in Watertown.”
- Bisnow, large office-to-residential conversion proposed in Watertown.
- Boston Business Journal, 9 Galen Street housing proposal and zoning.
- Watertown News, developer looks at turning the old mill building into housing with retail.
- BLDUP, 285-unit mixed-use redevelopment planned in Watertown Square.
- Newmark, Boston Life Science Market Report, Q1 2026 (lab vacancy 35.9%, availability 36.6%).
- Cambridge Planning Board, KS Partners two-year special permit extension request, 815 Somerville Avenue (Case #PB-402), March 6, 2026.
- Cambridge Planning Board, 815 Somerville Avenue original special permit application, 2024.
- Boston Real Estate Times, Cambridge lab conversion put on hold as the market softens.
- MassDevelopment, largest office-to-residential conversion in Massachusetts moves forward in Worcester (10 Chestnut Street, 198 units).
- City of Boston, Planning Department advances largest downtown office-to-residential conversion (280-300 Washington Street, 255 units).
- Mass.gov, Commercial Conversion Tax Credit Initiative.
- Mass.gov, Healey-Driscoll administration launches initiative to transform commercial spaces into homes.
- Redfin, Watertown, MA housing market data (2026).
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