scorecardresearch Skip to main content
The Argument

The Argument: Should accessory dwelling units be allowed statewide in Massachusetts?

Read two views and vote in our online poll.


Amy Dain

Public policy consultant and researcher; Newton resident

Amy Dain

Massachusetts needs many more accessory dwelling units, but local zoning significantly prevents their development. We can either leave it to municipal leaders and pro-housing activists in 351 separate cities and towns to reform these zoning rules, or have the Commonwealth simply allow ADUs across the state.

The local approach will take a century, for no particular benefit, compared to the efficient statewide approach.

Allowing production of more ADUs — often called in-law apartments — addresses our housing affordability crisis in three ways. Typically ADUs are priced relatively affordably for being smaller in size than most residences. New housing supply reduces the scarcity that drives price escalation. In addition, ADU liberalization will bring down construction costs by supporting the growth of a competitive industry delivering ADUs at scale.


Housing advocates have been campaigning for ADU reform for decades. Most Boston-area municipal master plans and housing plans adopted since the 1990s have recommended allowing ADUs.

Yet by 2018, out of 100 cities and towns surveyed in Greater Boston, only 37 allowed ADUs to be added and rented out, on at least some properties. Another third of municipalities allowed for ADUs, but only for residency by relatives or caretakers of the homeowners, not for rental. If you cannot rent the accessory home out after your relative moves out, you might opt against building it in the first place unless you can afford a guest or office wing.

The cities and towns that “allow” ADU rentals still highly restrict the qualifying properties. They promulgate requirements discouraging ADU building and increase the cost, and all do it in their own ways.

Reform of local zoning, town by town, is not straightforward paperwork for town administrators. It is political and legislative, involving direct democracy (town meeting) in the majority of municipalities. And ADUs are just one of many issues for municipalities to take up.


Indeed, the attention of local advocates and planners is needed for tougher land use puzzles that benefit from local oversight, like the redevelopment of decaying strip mall corridors, improvement of historic Main Streets, and zoning for transit-oriented development. For ADU policy, there is no benefit to local innovation and tailoring. ADU reform is a heavy lift for locals, and an easy move for the state.


Alexander Whiteside

Alexander Whiteside Laurie McEachern

Former Milton Planning Board member; former chief counsel, Massachusetts Department of Housing and Community Development

There have been recent proposals for legislation to require all cities and towns to allow construction of small apartments (sometimes called “accessory dwelling units”) by owners of single-family homes. ADUs could be located in altered interior spaces, basements, attics, garages, and detached buildings. The owners could construct these ADUs free from a variety of existing zoning limitations, including the need for securing a special permit. There’s been no reliable projection of how much new development would likely result under such legislation.

The special permit procedure is a foundation of Massachusetts zoning practice. It provides significant flexibility in enabling projects that are exceptions to general zoning rules. In most cities and towns, creation of an ADU has been treated as an exception to zoning for single-family use and hence requires a special permit.

The special permit procedure requires an application describing the ADU proposal by the owner and provides for notification of neighbors and interested persons. The zoning board of appeals conducts a hearing and issues a decision. It cannot arbitrarily deny a permit, but can impose reasonable conditions. It can also specify measures to require that the ADU is kept in good repair with consequences if it is not properly maintained.


The special permit process promotes well-designed projects. It does so at reasonable cost without imposing undue delay.

ADUs are not considered to be below-market “affordable housing units” and as such do not help a community reach the requirement under the state law, Chapter 40B, to have 10 percent of its housing stock affordable. It can be anticipated that, if allowed statewide, rents of ADUs would generally be at market levels and that the units would not serve those for whom there is the most critical housing need, including moderate-income families.

ADUs are managed by the homeowners as landlords who set the rents, choose the tenants, and have numerous legal responsibilities. Many homeowners are not well qualified to be landlords. Unprofessional management of rental apartments can cause very significant landlord-tenant problems and consequent municipal headaches.

Good zoning is the essence of good development. If local zoning rules are too stringent, they can be modified. However, imposing a statewide zoning requirement simply to spur new development is a poor planning practice, and the results usually so attest.

As told to Globe correspondent John Laidler. To suggest a topic, please contact

This is not a scientific survey. Please only vote once.