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Watertown Mall latest to potentially become ... lab space

Alexandria is pushing ahead with plans to redevelop the Watertown Mall into a life science campus. Don’t worry, though, the Target and RMV will stay.

Alexandria Real Estate Equities has proposed a large-scale lab and office campus at what is now the Watertown Mall and some neighboring properties.Alexandria Real Estate Equities

Life-science developer Alexandria Real Estate Equities is moving forward with plans to transform the Watertown Mall into a 24.5-acre lab campus, filing a master plan for a multibuilding project along Arsenal Street that would span nearly 1 million square feet.

The master plan, filed with Watertown officials in April, calls for four new life-science laboratory and office buildings, two amenity buildings — one with fitness and wellness uses, and another with food and beverage uses — and a building with a mix of office and retail, all keeping to a maximum height of five stories. Alexandria would also develop two parking garages — one at 480 Arsenal Way and one abutting the existing Target store (which would stay as part of the redevelopment) at 550 Arsenal St.


“The Project has been thoughtfully designed to provide a new, dynamic mixed-use development with numerous public realm improvements intended to embrace two important corridors in East Watertown — Arsenal Street and the Watertown-Cambridge Greenway — and to greatly enhance pedestrian and bicycle connectivity,” the developers wrote in an April master plan special permit filing to Watertown officials.

A rendering of Alexandria Real Estate Equities' proposed Watertown Mall lab campus looking toward a greenway.Alexandria Real Estate Equities

The new buildings would replace a portion of the old one-story mall and its surface parking lot, as well as buildings just west of it at 446, 458, and 500 Arsenal St. The Target store, which is an anchor of the property today, would remain in place, the filing shows, while the busy Registry of Motor Vehicles service center that is currently in the mall would also be included in the new development, said MassDOT spokesperson Jacquelyn Goddard said.

“Our physical office will move to another location on that site,” Goddard said in an e-mail. “We do not have a timeline yet.”

Alexandria bought the Watertown Mall in 2021 for $130 million, two years after it bought the former athenahealth campus about a half-mile down Arsenal Street and launched plans for a major lab redevelopment there. The lab developer’s continued work in Watertown comes as it’s pulling back in other Boston suburbs — Alexandria last month confirmed it was halting plans to transform a Newton office campus into lab and would instead sell the property.


A rendering of the northeast entry of a proposed amenity building at Alexandria Real Estate Equities' proposed Watertown Mall lab campus.Alexandria Real Estate Equities

The Watertown Mall project is located on the north side of Arsenal Street between Talcott Avenue and Elm Street. It’s across Arsenal Street from what’s now Arsenal Yards, Boylston Properties’ mixed-use redevelopment of the former Arsenal Mall that includes apartments, a hotel, life-science space, and some 250,000 square feet of retail.

The Watertown Mall project includes six acres of open space of “shaded walks, courtyards, plazas, and reforested areas” along with “substantial new planting.”

“The opportunity to create open space of this scale and quality is rare, and the redevelopment plan focuses on urban placemaking in the context of civic goals,” the master plan filing states. The project’s design team includes architecture firms Reed Hilderbrand, NBBJ, Gensler, and Höweler + Yoon, along with engineering consultant Buro Happold and land surveyor Feldman Geospatial.

Hearings at Watertown’s planning board and zoning board have not yet been scheduled, according to the Watertown website. An Alexandria representative declined comment on the project’s anticipated timeline or cost.

Catherine Carlock can be reached at Follow her @bycathcarlock.