The presentation, dated March 11, 2019, includes slides used to present the information necessary to understand the rationale for zoning changes, the location of the zoning areas under consideration and the charts, tables and maps that help describe the situation. The proposed zoning changes, especially articles 6, 7, 8, 11 and 16, only cover changes affecting about 7% of the Town, those parts of the Town that are currently zoned R4-R7 and the B zoning districts.
Related articles
(This post was originally an email message, discussion open space changes proposed by an Affordable Housing article during the Arlington, MA’s 2019 town meeting. It’s also a decent description of our town’s open space laws.)
Sorry this turned out to be a long post. Our open space laws are kind of complicated.
Arlington regulates open space as a percentage of gross floor area, rather than as a percentage of lot area. Let me give a concrete example: say we have a-one story structure with no basement. It covers a certain percentage of the lot area, and has an open space requirement based on the gross floor area (i.e., the interior square footage of the building).
Now, suppose we want to turn this into a two- or three-story structure. The building footprint does not change, and it covers exactly the same percentage of the lot area. However, the open space requirements double (if you’re doing a two-story building), or triple (if you’re doing a three story building). If that quantity of open space isn’t on the lot, then you can’t add the stories.
For this reason, I’d argue that our open space regulations are primarily oriented to limiting the size of buildings. You really can’t allow more density (or taller buildings) without reducing the open space requirements. Alternatively, if the requirements were based on a percentage of lot area, we probably wouldn’t need a reduction. (Cambridge’s equivalent is “Private Open Space”, and they regulate it as a percentage of lot area.)
The other weird thing about our open space laws is that we define “usable open space” in such a way that it’s possible to have none. (Usable open space must have a minimum horizontal dimension of 25′, a grade of 8% or less, and be free of parking and vehicular traffic). I live on a nonconforming lot that does not meet these requirements, as do the majority of homes in my neighborhood.
Suppose I wanted to build an addition, which would increase the gross floor area. With the non-conformity, I’d have to go in front of the ZBA and show that the current lot has 0% usable open space, and that the house + addition produces a lot with 0% usable open space. Because 0% = 0%, I have not increased the nonconformity, and would be able to build the addition, provided that all of the other dimensional constraints of the bylaw are satisified. Although this isn’t directly related to Article 16, it’s an amusing side effect of how the bylaw is written.
Finally, roofs and balconies. Section 5.3.19 of our current ZBL allows usable open space on balconies at least six feet wide, and on roofs that are no more than 10′ above the lowest occupied floor. We allow 50% of usable open space requirements to be satisfied in this manner.
The relevant section of Article 16 would create a 8.2.4(C)(1) which includes the language
Up to 25% of the landscaped open space may include balconies at least 5 feet by 8 feet in size only accessible through a dwelling unit and developed for the use of the occupant of such dwelling unit.
Article 16’s incentive bonuses strike the usable open space requirement, and double the landscaped open space requirement. With only landscaped open space, 5.3.19 doesn’t apply (it only pertains to usable open space). The language I’ve quoted adds something 5.3.19-like, but for landscaped open space. I say 5.3.19-like because it has a 25% cap rather than a 50% cap, and requires eligible balconies to be at least 5’x8′, rather than 6′ wide.
Here are a few pieces of supporting documentation:
- definitions of landscaped and usable open space from our ZBL
- a diagram to illustrate the difference between landscaped and usable open space.
- The text of section 5.3.19 (which is referenced by the diagram)
- the main motion for Article 16
Dave Weinstock, an Arlington resident interested in affordable housing wondered about the concept of “developer math”. The math involved in planning an affordable housing projects is a problem that needs to get solved in order to have anything built here in Arlington, or anywhere. This topic comes up frequently in community discussions about the need for more housing.
Questions are raised around:
- 1- Why build so many units vs. smaller buildings
- 2- Why parking is costly and inefficient use of land
- 3- Why can’t more affordable or all affordable units be built?
- 4- The cost of subsidizing affordable units and how that may translate to higher rental rates/costs, etc.
Dave found a great Architecture and Development firm in Atlanta (Kronberg Urbanists + Architects, based in Atlanta GA) that lays out a nice presentation, includes sample proformas, and real life scenarios that may help us understand this piece of the puzzle better when evaluating any project and how developers may be incented to build certain types of projects or do certain types of work.
Here is a link, reformatted to be within this website, to the presentation, showing the varieties of choices, costs, formulas and outcomes developers consider before deciding if the project can be built: https://equitable-arlington.org/developer-math_kua_071420/
Much of our hope for more affordable housing depends on the market forces of capitalism and the willingness of developers to build for good, not just for profit. But the developers must be able to cover their costs. Many communities are highly skeptical of developers, assuming the community will get tricked, the developer will get greedy and the promised housing will be a disappointment. Trust is needed. But so is verification. We all need to learn the developer math.
What are the math factors that a developer considers before deciding to build affordable housing?

Here is a link to the original presentation. https://www.kronbergua.com/post/mr-mu-let-s-talk-about-math
The calculation for what is permanently affordable housing is complicated. Arlington’s affordable rate is based on a region that includes the Area Median Income (AMI) of the Cambridge-Boston-Quincy region. The rate is adjusted and reset periodically according to federal HUD guidelines. The rate is applied based on family size and on the Town’s definition of what income level is eligible for Inclusionary Housing opportunities in Arlington. In Arlington a 3 person family would qualify if their income was under 60% of AMI. At this time, that is approximately $58,000 for a family of three.
For more information, see this table of income limits from Cambridge’s Community Development Department, and this short paper on affordable housing from the City of Boston.
Prepared by: Barbara Thornton with the capable assistance of Alex Bagnall, Pamela Hallett, Patrick Hanlon, Karen Kelleher, Steve Revilak and Jennifer Susse.
As Arlington considers new zoning and other policy decisions to increase the amount of affordable housing in the town, a concern has been raised about the threat of greater costs to the Town’s budget from new people with school age children moving into the town. The concern: additional children in the public schools costs the town more than the additional new property tax revenue the Town collects from the new housing.
This post examines this concern, drawing on data from two recent housing developments, representing 283 units of housing in Arlington, to determine that actually the Town budget gains over 4.5 times the actual cost of paying for the students. According to the most recent 2020 tax bills, the Town expects to collect $1,250,370 in revenue and to spend an additional $269,589 for the new Arlington Public School students living in these developments.
The data suggests that the fear of increased school costs, overwhelming the potential new revenue from new housing construction is not warranted.
For more information, see the full post here.
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.
This letter appeared in the Boston Globe on Dec. 19th. It’s reprinted
here with permission from the author, Eugene Benson.
The Dec. 12 letter from Jo Anne Preston unfortunately repeats misinformation making the rounds in Arlington (“Arlington is a case study in grappling with rezoning“).
At April Town Meeting, the Arlington Redevelopment Board recommended a vote of no action on its warrant article that would have allowed increased density along the town’s commercial corridors in exchange for building more affordable housing (known as “incentive zoning”), when it became obvious that the article would be unlikely to gain a two-thirds vote for passage, in part because of the complexity of what was proposed.
A warrant article to allow accessory dwelling units in existing housing (“in-law apartments”) gained more than 60 percent of the vote at Town Meeting but not the two-thirds vote necessary to change zoning.
The letter writer mentioned “naturally occurring affordable apartment buildings.” The typical monthly rent for an apartment in those older buildings ranges from about $1,700 for a one-bedroom to about $2,300 for a two-bedroom, according to real estate data from CoStar. Those are not affordable rents for lower-income people. For example, a senior couple with the national average Social Security income of about $2,500 per month would spend most of their income just to pay the rent.
We need to protect the ability of people with lower incomes to withstand rent increases and gentrification. That, however, requires a different approach than hoping for naturally occurring affordable housing to be there even five years from now.
Eugene B. Benson
Arlington
The writer’s views expressed here are his own, and are not offered on behalf of the Arlington Redevelopment Board, of which he is a member.
A recently constructed project with 44 units of affordable housing shares a footprint with a new public library in this Chicago neighborhood. The Mayor and the Housing Authority initiated a competition for proposals from architecture firms to build projects that feature the “co-location” of uses, “shared spaces that bring communities together”, according to a recent article by Josephine Minutillo in ARCHITECTURAL RECORD (October 2019).
This project is an excellent example of how a municipal policy (increasing affordable housing) can drive creativity to meet policy goals. This project resulted from a combination of publicly owned land, municipal initiative, a quasi public housing agency expertise and a private architecture/ developer with a commitment to affordable housing. Could a project like this work in Arlington MA?
Some years back, I took a bus ride to a climate rally in New York City with a bunch of other activists. My seatmate was 12 years old, a smart kid from the suburbs who had never been to New York. As we approached Manhattan on the Cross Bronx Expressway, he looked out at a block of concrete apartment buildings and said something like: This is what happens when you don’t care about the environment. Actually, I replied, this is green living: People live close together; they can walk or take public transit; they live in apartments, share walls and heat and are relatively energy efficient; their carbon footprint is far lower than a family in a “green”, leafy single-family suburban house.
But my traveling companion was not altogether wrong about what he saw: New York, Boston, and every other city are now at pains to make a humane, equitable adaptation to a changing climate. We don’t want to create living spaces that bake in the sun’s heat, that have no shade or greenery or open space, surrounded by asphalt and highway, beset with deadly particulate pollution, flooding risk, and polluted stormwater runoff. Heat and air pollution are an expensive and deadly burden that fall especially heavily on low- and middle-income folks — a burden cruelly increasing with climate change.
As we decide what kinds of housing we are going to encourage in Arlington, we can do things in a more compassionate and inclusive way. We can incorporate environmental and aesthetic concerns, while allowing a mix of housing types that accommodate people of diverse incomes, family sizes, and life stages.
We can address both the climate crisis and the crisis-level housing shortage in Greater Boston. Environmental concerns are not a reason to say no to new housing. Rather, they are a part of the housing solution, in Arlington and regionally.
As Laura Wiener detailed in another post, The Housing Corporation of Arlington development at 10 Sunnyside (between Broadway and Mystic Valley Parkway, near Route 16), is an excellent example of implementing environmental/sustainability measures in an affordable (i.e. income-subsidized) multi-family dwelling. It is Passive House certified: An extremely stringent standard, using a combination of advanced and repurposed materials, high- and low-tech, to provide human comfort while bringing energy use to an absolute minimum.* The development features plentiful bike parking and a roof garden. It converts previously impervious pavement to landscaping, like planters, where stormwater can infiltrate the ground rather than carrying unfiltered pollutants into Arlington’s water bodies.
Another example of green infrastructure lives charmingly and unassumingly on some of our street corners. In 2020, Arlington installed rain gardens at the corner of Milton Street and Herbert Road in East Arlington. These little curbside oases act as a kind of green filter for storm water, catching pollutants (Fertilizer! Salt! Dog poop! Oil! Brake dust!) before they reach Alewife Brook and the Mystic River. Perhaps co-sited with new housing, wider buildout of rain gardens could keep nutrient pollution out of Spy Pond, preventing nasty algae growth which literally suffocates other aquatic life.
A caveat: We must take care not to load so many creative requirements onto new housing that it doesn’t get built at all. We need the housing. (See “The Problem with Everything-Bagel Liberalism” by Ezra Klein in the New York Times.) And under the new MBTA Zoning that we are required to implement, we must allow three-family housing in our new multi-family zones by right, i.e. without extra requirements or rigamarole.
But we could decide to add incentives to allow more housing above those requirements if such environmental improvements (rain gardens, green roofs, pollinator habitat, Passive House innovations, etc.) are included. Every new building is an opportunity for environmental adaptation. A vision for a greener, cooler, more inclusive Arlington takes shape. We can do this.
New housing development provides an opportunity to incorporate inclusive, environmentally friendly, win-win adaptations. Our environmental and housing goals must not be in tension with each other. With a coordinated approach, we can address the challenges of pollution, climate change, and our chronic and unjust housing shortage.
*As far as I can tell, only two other buildings in all of Greater Boston are Passive House certified: A new multi-family in Roxbury, and a single-family in Somerville.