Accessory Dwelling Units

Accessory Dwelling Units (aka “granny flats”)

The following information was presented to the Arlington Redevelopment Board in October, 2020 by Barbara Thornton, TMM, Precinct 16

This Article  proposes to allow Accessory Dwelling Units, “as of right”, in each of the 8 residential zoning districts in Arlington.

Why is this zoning legislation important?

Arlington is increasingly losing the diversity it once had.  It has become increasingly difficult for residents who have grown up and grown old in the town to remain here.  This will only become more difficult as the effects of tax increases to support the new schools, including the high school, roll into the tax bills for lower income residents and senior citizens on a fixed income.  For young adults raised in Arlington, the price of a home to buy or to rent is increasingly out of reach.

Who benefits from ADUs?

  • Families benefit from greater flexibility as their needs change over time and, in particular providing options for older adults to be able to stay in their homes and for households with disabled persons or young adults who want additional privacy but still be within a family setting.
  • Residents seeking an increase in the diversity of housing choices in the Town while respecting the residential character and scale of existing neighborhoods; ADUs provide a non-subsidized form of housing that is generally less costly and more affordable than similar units in multifamily buildings;
  • Residents wanting more housing units in Arlington’s total housing stock with minimal adverse effects on Arlington’s neighborhoods.

What authority and established policy is this built on?

Arlington’s Master Plan is the foundational document establishing the validity and mission for pursuing the zoning change that will allow Accessory Dwelling Units.

Under Introduction in Part 5, Housing and Residential Development, the Master Plan states:  Arlington’s Master Plan provides a framework for addressing key issues such as affordability, transit-oriented residential development, and aging in place.

The Master Plan states that the American Community Survey (ACS) reports that Arlington’s housing units are slightly larger than those in other inner-suburbs and small cities. In Arlington, the median number of rooms per unit is 5.7.  There is a great deal of difference in density and housing size among the different Arlington neighborhoods.  The generally larger size of homes makes it easier to contemplate a successful move to encourage ADUs.

What do other municipalities do?

According to a study (https://equitable-arlington.org/2020/02/16/accessory-dwelling-units-policies/), by 2017 65 out of 101 municipalities in the greater Boston (MAPC) region allowed Accessory Dwelling Units by right or by special permit. The average number of ADU’s added per year was only about 3.  But by 2017, Lexington had 75 ADUs and Newton had 73.  Both of these communities were among about 10 “as of right” municipalities in the MAPC region.  This finding suggests that communities with more restrictions are less likely to see any significant affordable housing benefits.

Even in the midst of a housing crisis in this region, according to Amy Dain, housing expert, (https://equitable-arlington.org/2020/02/18/zoning-for-accessory-dwelling-units/) most municipalities still have zoning laws that restrict single family home owners from creating more affordable housing.

And this is despite the fact that, as according to Banker & Tradesman, March 10, 2020: https://www.bankerandtradesman.com/63-percent-in-greater-boston-back-adus/, 63% of people in the region approve of ADUs.  California has recently passed strong pro-ADU legislation.  A study by Zillow further corroborated this strong interest in communities across the US, including our region.  https://equitable-arlington.org/2020/03/10/adu-popularity/.

Learn more about Accessory Dwelling Units/ “Granny Flats” here: https://planning.org/knowledgebase/accessorydwellings/