By Charlie Breitrose

Life science companies are increasingly choosing Watertown, with dozens of biotech companies already in town and new space being developed to make way for more.

Among the companies growing here is cell therapy company SQZ Biotech, which signed a nearly 64,000 square foot lease at Arsenal Yards, shortly after Arsenal developers Boylston Properties and The Wilder Companies announced plans to add even more biospace to its project.

“Watertown is becoming known as a desirable address for the innovation economy — for clusters such as life sciences,” said Arsenal Project Manager Andrew Copelotti.

At last count, Watertown is home to 23 life sciences companies employing about 1,500 people. Plus a life sciences incubator was recently opened in Watertown by Cambridge Scientific.

Boylston principal Bill McQuillan said Watertown has an advantage over the center of the biotech industry, Kendall Square, because it offers significantly lower prices while being minutes away from Kendall.

A triple net lease for lab space in Cambridge can attract rents in the $90 per square, compared to about $50 in Watertown, the Boston Globe recently reported. Overall, lab inventory in Watertown has grown by 56 percent over the past decade.

Boylston switched directions at Arsenal Yards after an unsuccessful effort to build a 197-foot condominium building in 2018, after hearing significant public opposition.

Boylston presented its latest vision for Building G at a community meeting in late January. The proposed building would be 130 feet and nine stories tall with 155,00 sq. ft. of office and lab space, according to the architect, Adam Gross of Ayers Saint Gross.

The proposal received mostly positive reviews from the public at the meeting, but some worried about its proximity to the Charles River and the adjacent Arsenal Park.

Previously, Boylston announced the conversion of the top floor of one of the historic buildings on the site into 200,000 sq. ft. of biotech space at Arsenal Yards, with SQZ (pronounced “squeeze,”), as its first announced tenant.

Arsenal Yards will still include 300 apartments, more than 50 retailers and restaurants, a Roche Brothers supermarket, a seven-screen Majestic Theater and 150-room Hampton Inn & Suites by Hilton.

Boylston has previous experience building biotech space, having put up the 185,000-square-foot Linx, a lab and office building on a former Verizon facility off Arsenal Street, which sold last year for close to $158 million to Clarion Partners.

Other buildings that have become home to R&D companies are Riverworks (the former Aetna Mills) on Pleasant Street, and the building at 65 Grove Street.

The bio boom is also moving across the Charles River into Newton, with the recent opening of LabShares, an office and laboratory incubator for emerging biotechnology and life science companies on Bridge Street in the Charles River Mill District.