Figures current as of October 21, 2026. The zoning and project status are due for a review in April 2027, and the sale price and mortgage rate in January 2027.
Arlington's MBTA Communities zoning lets the owner of a lot on Massachusetts Avenue or Broadway build a four-story apartment building as of right, with no minimum lot size and no units-per-acre cap. Here's what the Arlington MBTA 3A overlay allows, what the town has already approved under it, and the arithmetic that tells you whether your Arlington two-family is worth more as a house or as a building site.
- The Executive Office of Housing and Livable Communities approved Arlington's MBTA Communities districts on February 12, 2024, counting 3,120 units of capacity on 115.5 acres against a required 2,046 units, per the EOHLC district approval letter.
- Arlington adopted the overlay as Article 12 of its October 2023 Special Town Meeting by a vote of 189 to 35, per the Town Clerk's certified vote and bylaw text.
- In Arlington's Mass Ave/Broadway Multi-Family district, multifamily housing is allowed as of right at four stories and 52 feet, subject to Redevelopment Board site plan review, with no minimum lot size, frontage, or lot area per unit, per the same certified bylaw text.
- The Arlington Redevelopment Board approved a six-story, 28-unit affordable building with ground-floor commercial space at 840-846 Massachusetts Avenue on March 9, 2026, per the Town of Arlington's decision notice.
- Freddie Mac's average 30-year fixed mortgage rate was 7.40 percent for the week of October 15, 2026, per the Primary Mortgage Market Survey.
What does Arlington's MBTA zoning allow on Mass Ave and Broadway?
A four-story, 52-foot multifamily building, as of right, on any lot inside the Mass Ave/Broadway Multi-Family district, which the bylaw abbreviates MBMF. As of right means the Redevelopment Board reviews the site plan but can't deny the use itself, which is a very different conversation from asking a board for a special permit.
What's missing from the rules matters as much as what's in them. The MBMF district sets no minimum lot size, no minimum lot area per unit, no frontage minimum, and no open space or floor area ratio requirement. The number of units a lot can hold comes out of the building envelope, the parking, and the site plan, not out of a density formula.
The second district, Neighborhood Multi-Family, sits on side streets near the corridors and allows three stories and 35 feet with no height bonuses. An owner picks either the overlay or the underlying zoning for a project, not a mix of both. The full map and the state compliance picture live on our MBTA 3A zoning hub for Greater Boston.
How tall can a building get on Mass Ave or Broadway with the bonuses?
Six stories and 78 feet on Mass Ave, and five stories and 65 feet on Broadway, which is the ceiling no combination of bonuses can break.
The biggest bonus is for ground-floor commercial space. A project that puts at least 60 percent of its ground floor into commercial use, with no ground-floor apartments and at least 80 percent non-residential frontage, can reach the six-story cap on Mass Ave or the five-story cap on Broadway, and can build to a zero front setback.
The other bonuses add a story at a time. A project with 22.5 percent affordable units gets one extra story, and on Mass Ave only, 25 percent affordable gets two. A building certified LEED Gold gets one more. Above the third story, the street-facing walls have to step back 7.5 feet, so the top floors are smaller than the footprint.
The affordability and parking rules
Projects of six or more units fall under the town's inclusionary rule, and the state's approval was written around 10 percent of units affordable at 80 percent of area median income. That makes five units the largest project with no affordable unit at all, which is a line worth designing around.
The overlay has no special parking minimum of its own. Projects follow Arlington's standard parking section, which allows half the spaces to be compact and requires none for the commercial space, with reductions available.
What has Arlington actually approved under the overlay?
Several projects on both corridors have cleared the Redevelopment Board, which means the rules are being used, not just written down.
The Housing Corporation of Arlington's plan at 840-846 Mass Ave and 17 Newman Way adds a six-story building with 28 affordable units and a commercial space, plus a three-story, 12-unit building, while keeping the 57 apartments already on the site. The board approved it on March 9, 2026.
On Broadway, the board approved a five-story, 28-apartment building with one commercial space, six affordable units, and 12 parking spaces at 126-128 Broadway by a 4 to 1 vote on April 6, 2026, according to a resident's published notes from that Redevelopment Board meeting. Twelve spaces for 28 apartments is the parking flexibility in practice.
The smaller cases are the ones most owners should study. A four-unit, four-story building at 225 Broadway came before the same board, and that's the scale a single house lot can actually support. When we run a parcel card for an owner on Mass Ave or Broadway, the first check is whether the lot sits inside the overlay map at all, before anyone talks about stories.
What this means if you own a house on Mass Ave or Broadway in Arlington
If you own a two-family or three-family inside the MBMF district, your property now has two values: what a family pays to live in it, and what a builder pays for the right to put four to six stories on the land. You only see the second number if someone underwrites it.
Start with the house value. A two-family at 28 Forest St. in Arlington sold for $1,000,000 on October 5, 2026, against an original asking price of $1,199,500, per the Town and Country Realty listing record. Use that as the as-is benchmark for a corridor two-family in decent shape.
Then divide. If your lot could hold eight units, a builder has to pay $125,000 per buildable unit of land to match that $1,000,000. At twelve units the break-even falls to about $83,000 a unit. Whether a builder will pay that depends on construction cost, rents, and money that costs 7.40 percent, so the break-even is the question, not the answer.
The long-held owner with no mortgage has the most room here. You can sell as a house, sell as a site, or hold and rent while the corridor fills in around you. Each of those prices differently, and the worst outcome is selling as a house to a buyer who already ran the site math.
Frequently asked questions about Arlington's MBTA zoning on Mass Ave and Broadway
How many stories can you build under Arlington's MBTA zoning on Mass Ave?
Arlington's Mass Ave/Broadway Multi-Family district allows four stories and 52 feet as of right on Massachusetts Avenue, and up to six stories and 78 feet with a qualifying ground-floor commercial use or affordability and green building bonuses.
How tall can a building be on Broadway under Arlington's MBTA overlay?
On Broadway, Arlington's overlay allows four stories and 52 feet as of right, and a maximum of five stories and 65 feet with bonuses.
Is there a minimum lot size in Arlington's MBTA Communities district?
No, Arlington's Mass Ave/Broadway Multi-Family district sets no minimum lot size, no minimum lot area per unit, and no frontage requirement, so building size is governed by height, step-backs, parking, and site plan review.
Do small projects in Arlington's MBTA overlay need affordable units?
Projects of six or more units in Arlington's overlay must include affordable housing, and the state's February 2024 approval was based on 10 percent of units affordable at 80 percent of area median income.
Is Arlington compliant with the MBTA Communities Act?
Yes, the Executive Office of Housing and Livable Communities found Arlington compliant on February 12, 2024, counting 3,120 units of zoned capacity against a requirement of 2,046.
The next step if you own on Mass Ave or Broadway in Arlington
Ask for a highest and best use review of your parcel before you list, refinance, or answer a builder's letter. PH Realty Group confirms whether your lot is inside the Mass Ave/Broadway district, works out what the overlay lets you build on it, and puts the site value next to what the house sells for as it stands.
Start with our multifamily and redevelopment investing services, or request a valuation of your Arlington property as it stands today. Ethan Piani-Hohmann, PH Realty Group, (781) 879-0863, [email protected].
