In-law apartment. Granny flat. Basement apartment. Ancillary unit. Known by many different names, accessory dwelling units (ADUs) could soon be allowed as of right in all Boston neighborhoods.

In November 2017, Boston launched an 18-month pilot and amended its zoning laws in three neighborhoods (East Boston, Jamaica Plain and Mattapan) to allow ADUs as of right. Now, with the 18-month pilot ending soon, Boston is considering and holding public meetings on enacting a city-wide zoning amendment to allow ADUs.

In-law apartment. Granny flat. Basement apartment. Ancillary unit. Known by many different names, accessory dwelling units (ADUs) could soon be allowed as of right in all Boston neighborhoods.

What the pilot does:
The pilot amended Article 53 (East Boston Neighborhood District), Article 55 (Jamaica Plain Neighborhood District) and Article 60 (Greater Mattapan Neighborhood District) to allow a homeowner to create small, independent units so long as:

▪ The ADU is created within a one, two or three family home;

▪ The home is owner occupied;

▪ The ADU does not extend beyond the building envelope (no bump outs, no attached units and no detached units);

▪ Construction meets building code and safety requirements; and

▪ ADUs, when used as a rental, are registered with ISD’s rental registry.

The pilot allows a homeowner to add a unit in the basement or attic or to divide their home to create a new unit that can be used as a rental, to house aging parents or accommodate children returning to the nest.

What Boston hopes to achieve:
The City of Boston launched the ADU pilot to increase affordable housing options, legalize illegal rental units, help people remain in their homes by allowing them to create a revenue source through rental income and to support multi-generational family arrangements.

What’s next for ADUs:
Boston is now considering a city-wide zoning amendment to allow ADUs. The Boston Planning & Development Agency held its first public meeting on February 25, 2019 to receive input. At this time, the contemplated city-wide zoning change would have the same limitations as the pilot. It does not appear that a city-wide zoning amendment will expand the type of ADU to include detached or attached units. In other words, for example, the City is not contemplating allowing a garage or carriage house to be converted to an ADU as of a right; a homeowner would still need a variance. Nor would a city-wide amendment necessarily allow, as of right, the placement of a tiny house in a homeowner’s backyard. Any ultimate zoning amendment could, of course, change as the City of Boston receives feedback on the pilot. There is both support for expanding housing typologies and increased density as well as concern about the impact on neighborhood character and burdening of neighborhood resources.