The Green Line Extension and Somerville homes: what changed and what it means for owners
The Green Line Extension in Somerville: stations, opening dates, MBTA Communities zoning, ADU parking rules near transit, and what it means for your home.
Mateus MagnoLicensed Construction Supervisor · November 2, 2026 · 4 min read
The Green Line Extension added six stations: Union Square, East Somerville, Gilman Square, Magoun Square, Ball Square and Medford/Tufts, plus a rebuilt Lechmere. The Union Square branch opened March 21, 2022, and the Medford branch opened December 12, 2022. Near stations, state law bars towns from requiring parking for protected ADUs.
The Green Line Extension changed how a lot of Somerville gets around. Neighborhoods that used to be a long walk or a bus ride from rapid transit now have a station within reach, and that changes how homeowners think about their houses.
Here are the facts about the Green Line Extension, the state rules tied to transit, and what I see when I renovate or plan ADUs near the new stations in Somerville, Cambridge and Medford.
The Green Line Extension: stations and dates
According to the MBTA's GLX project page, the project rebuilt and relocated Lechmere station in Cambridge and added six new stations.
| Branch | Stations | Opened |
|---|---|---|
| Union Square branch (D) | Union Square | March 21, 2022 |
| Medford branch (E) | East Somerville, Gilman Square, Magoun Square, Ball Square, Medford/Tufts | December 12, 2022 |
The Union branch runs on the Fitchburg commuter rail corridor and the Medford branch on the Lowell corridor. The City of Somerville notes the Community Path extension opened in June 2023. It runs from Lowell Street through Somerville Junction Park toward Cambridge Crossing, on MBTA land, and the city operates and maintains it.
What changed for Somerville neighborhoods
I can't point to official numbers on home values, so I won't make claims about prices. What I can share is what I see on the ground:
- Union Square: more cranes, new buildings and busier streets around the station area, which means tighter parking and deliveries for nearby jobs.
- Gilman Square and East Somerville: more owners asking about adding units or updating older two-families.
- Magoun Square and Ball Square: steady interest in kitchens, baths and backyard ADUs on the classic 1900 to 1930 lots.
- Medford/Tufts: projects that straddle the Somerville and Medford line, so I check which city's rules apply first.
MBTA Communities Act: zoning near transit
The state's MBTA Communities law (Section 3A of the Zoning Act) requires each MBTA community to have at least one zoning district of reasonable size where multi-family housing is allowed as of right. That district must have a minimum gross density of 15 units per acre and sit within 0.5 miles of a transit station where applicable.
On the state's compliance table, downloaded October 26, 2026, Somerville, Cambridge and Medford are all listed as Compliant.
Somerville was already ahead on this. When the city overhauled its zoning in December 2019, it repealed minimum parking requirements for most of the city, set parking maximums near Red, Orange and Green Line stations, and allowed backyard cottages. My Somerville zoning guide explains the districts.
State ADU rules and parking near stations
The state ADU law lets owners build an ADU by right in single-family zoning districts, starting February 2, 2025. The ADU must be no larger than 900 square feet or half the main home's floor area, whichever is smaller. For transit:
- A town cannot require any parking for an ADU within 0.5 miles of a commuter rail station, subway station, ferry terminal or bus station.
- Farther out, it cannot require more than one space.
With six new stations, a lot of Somerville is now close to rapid transit. My Somerville backyard ADU map shows which lots have room, and my 3D ADU designs show what fits.
What it means for renovating near a station
From my own projects in Greater Boston, building near the new stations comes with a few practical points:
- Check the zoning district first. Districts near squares can allow more than the side streets.
- Plan for no parking. If your design does not need a space, you may have more room for an ADU or a bigger yard.
- Expect neighbors close by. Noise, hours and dumpster rules matter; see my post on construction hours and dumpsters.
- Old houses are still old. Lead paint, knob-and-tube wiring and tired porches show up whether you are near a train or not.
- Think about who will live there. Many owners near the stations plan for a tenant, an aging parent or a grown child who would rather take the T than own a car. That shapes the layout, the entrance and how much storage you need.
Every lot is different, so I always confirm the zoning district, setbacks and any historic review with the city before we draw anything.
One of the largest projects near a new station is the 418-apartment plan at 90 Washington Street.
Need a hand?
Own a home near Union Square, Gilman, Magoun, Ball Square or Medford/Tufts? Book a free walkthrough and I will look at what your lot allows and send a written line-item budget, usually within 48 hours.
Frequently asked questions
When did the Green Line Extension open?
The Union Square branch opened on March 21, 2022, and the Medford branch to Medford/Tufts opened on December 12, 2022, according to the MBTA.
What are the Green Line Extension stations in Somerville?
Union Square, East Somerville, Gilman Square, Magoun Square and Ball Square, with the line ending at Medford/Tufts. Lechmere in Cambridge was also relocated and rebuilt.
Is Somerville compliant with the MBTA Communities Act?
Yes. On the state's compliance table downloaded October 26, 2026, Somerville is listed as Compliant, as are Cambridge and Medford.
Do I need parking for an ADU near a T station in Massachusetts?
Under the state ADU law, a town cannot require any parking for a protected ADU within 0.5 miles of a commuter rail station, subway station, ferry terminal or bus station.
Planning work near Somerville? See the towns I work in, with local permit notes, and how I price work.
Mateus Magno founded Magno & Co in 2020. He is a licensed Massachusetts Construction Supervisor (CS-123658), registered Home Improvement Contractor (HIC #220484) and certified Lead-Safe Renovator Supervisor who has renovated and managed over $5 million in projects across Greater Boston.
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