Accessory Dwelling Units: Policies, Attitudes in Boston Region

Massachusetts’ 2020 Economic Development Bill included a set of housing choice provisions: these require communities served by the MBTA to provide a district of reasonable size where multi-family housing is allowed by right. The law gives us significant flexibility to design a district that best suits our needs, but the district must allow housing suitable for families with children, without age restrictions, and at a rate of at least 15 dwelling units per acre. Arlington is one of 175 MBTA communities in Massachusetts that share in the responsibility for meeting these requirements.

The law requires a “district of reasonable size”, but what does that mean? Throughout much of 2021 the Massachusetts Department of Housing and Community Development (DHCD) worked on a set of supporting regulations that set the district requirements according to the type of transit service a community has, the number of existing homes in the community (as of the 2020 Census), and the amount of developable land near transit stations. The specifics vary by community, but here is what the requirements mean for Arlington:

• Our district needs a capacity of (at least) 2,046 homes. This isn’t a requirement to build 2,046 additional homes; instead, it reflects the total number of homes that district might contain in the future. For example, if a parcel with a two-family home were rezoned to allow a three-family home, that single parcel would have a capacity of three.
• Our district needs to allow multi-family housing by right. “By right” means that the development only requires a building permit, where the Building Inspector determines whether the project complies with zoning and building codes. While Arlington allows multi-family housing (three or more dwellings on a single parcel) in some areas, such projects are not allowed by right.
• Our district needs to allow (at least) 15 dwellings/acre. This is more or less in line with the density of the streetcar suburbs that were built in East Arlington during the 1920s. Although portions of Arlington likely meet the density requirement, none of these areas currently comply, as they don’t allow multi-family housing to be built by right.
• Our district needs to be at least 32 acres, but it could be larger. We have flexibility here, as we’ll discuss in a moment.
• Finally, due to the lack of developable land around the Alewife T station, Arlington is free to locate its multi-family district (or districts) anywhere in town. We’re not tied to any particular geographic location.

The new law’s requirements provide Arlington with a great deal of flexibility. We’re free to place our district (or districts) anywhere in town, and we’ll be able to choose from a variety of options as long as they meet the requirements set forth above. For example, providing the capacity of 2,046 homes in the minimum district size of 32 acres would give us a density of 64 dwellings/acre; roughly the scale of mid-rise apartment buildings. On the other hand, if we went with the minimum density of 15 dwellings/acre, we’d have a 135 acre district that allowed smaller multi-family homes. Our district can be anywhere within this range; we also have the option of having multiple districts, with smaller multi-family buildings in some areas of town and larger multi-family buildings in others.

Arlington has a track record of producing thorough and comprehensive planning documents, such as our Master Plan, Net Zero Action Plan, Sustainable Transportation Plan, and Housing Production Plan. These plans contain plenty of building blocks that could be used to formulate a compliant multi-family district. Viewed in that light, the MBTA community requirements are an opportunity to meet some of the goals we’ve already set for ourselves; we just have to go about it in a way that satisfies the law’s new requirements.

Arlington has one unique consideration, which doesn’t apply to most MBTA communities. In 2020, Arlington’s Town Meeting sent a home rule petition to the state legislature, asking for permission to regulate the use of fossil fuels in new building construction; it’s an important component of our plan to become carbon-neutral by 2050. A number of other communities in the Commonwealth filed similar petitions, and the legislature responded by establishing a pilot program: ten cities and towns will be allowed to enact “fossil fuel bans”, but only if they (a) have 10% subsidized housing, (b) achieve safe harbor via compliances with an approved housing production plan, or (c) establish a multi-family district of reasonable size by February 2024. Arlington doesn’t meet the subsidized housing requirement (only 6.54% of our homes are on the subsidized housing inventory), and we’re unlikely to gain safe harbor status during the next year; our most viable path to participation hinges on meeting the multi-family requirements.

In summary, the multi-family requirement for MBTA communities creates new requirements for Arlington, while also presenting us with new opportunities: the opportunity to meet planning goals, the opportunity to meet sustainability goals (e.g., by regulating fossil fuel use in new construction), and the opportunity to reimagine how we do multi-family housing in Arlington as our town moves forward into the twenty-first century.