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Is the answer to Massachusetts housing crisis coming to your backyard? Don’t hold your breath.

The state has struggled to craft clear guidelines for ‘in-law units’ and ‘granny flats’ that some call the ‘low-hanging fruit’ of housing policy.

Mary J. Casey, 90, with her daughter, Mary M. Casey, lives in the accessory dwelling unit that's attached to her son's Abington home.John Tlumacki/Globe Staff

Six years ago, facing one of the nation’s worst housing shortages, California lawmakers tried an experiment: They passed a series of laws making it easier for homeowners to construct a second, smaller home on their property — an accessory dwelling unit, in the parlance of housing policy.

This move did not end California’s housing crisis on its own. But in just a few years developers there have built tens of thousands of in-law apartments and granny flats, putting a real dent, advocates say, in the state’s housing shortage.

In Massachusetts, a state wrestling with a deep housing crisis of its own, legislators have not been nearly as decisive. Time and again, efforts to legalize ADUs statewide have fizzled on Beacon Hill, most recently last month, when a promising amendment died with the economic development bill. That leaves regulations up to cities and towns, creating a patchwork of local rules that developers say is nearly impossible to navigate at scale.

In most towns that have legalized ADUs in some capacity — as of 2018 there were 68 in Greater Boston that allowed them, and a number of others have legalized them since — only a handful of units are permitted each year. Many places still ban them outright.


The tension between statewide rules and local control of zoning is a constant in Massachusetts housing policy, and towns often push back on mandates from Beacon Hill. But housing advocates worry that if the state can’t even craft policy for something as modest as a backyard cottage, it will never tackle the bigger challenges.

“ADUs are the easiest low-hanging fruit,” said Amy Dain, a consultant and public policy researcher who has studied suburban zoning. “All we’re really talking about is letting people use their existing properties to create more housing. It’s hard for me to understand why we can’t find that agreeable.”


Where they are getting built, these extra units take various forms. There are the so-called tiny houses, widely popular in California, that occupy a backyard or sit alongside a house. And there are converted basement or attic apartments, more commonly found in cities. Regardless of style, any ADU must have its own kitchen and bathroom and meet certain code restrictions.

Kevin Whelan, a project manager with the company Backyard ADUs, stood outside of an accessory dwelling unit he helped construct in Abington.John Tlumacki/Globe Staff

The few that have popped up have already proved their worth.

Joe Casey and his sister, Mary, had been looking for a few years to build something for their elderly mother in Joe Casey’s Abington backyard before they got the process rolling in 2021. They wanted their mother to be close during Massachusetts’ icy winters, and they were in luck; Abington’s ADU laws allow the units to be constructed for immediate family members.

The approval process took about a year, and in June, a crane lowered a 480-square-foot unit — gray, to match the house — into the yard. One month of construction work extending the back deck and the roof, and their mother had sold her house in West Roxbury and moved in. The money she earned in her home sale paid for the construction costs.

“We’re just so pleased,” Joe Casey said. “She gets to have her own space, and I can make sure she’s not slipping down the stairs and getting hurt.”

Mary, his 90-year-old mother, agreed.

“We haven’t finished setting the place up inside,” she said, “but it feels like a home.”


There is little organized opposition to projects like the Caseys’. But for the last several years, proposals to legalize ADUs statewide have failed to make it through the Legislature. And when towns have allowed them, it has often been in a limited capacity through special permitting, not “by right” legalization that would issue a blanket OK, within certain parameters. That means zoning boards, public hearings, and sometimes angry neighbors.

Resident concerns run the gamut. Some fear allowing accessory units by-right will lead to overdevelopment of their neighborhoods. Others worry their towns don’t have the infrastructure to support an influx of small homes. And there are a select few concerned that the people moving into more affordable units will change the “character” of their neighborhoods. Passions can run high.

Chris Lee, founder and president of Backyard ADUs, one of the only companies in Massachusetts that specializes in building these units, has seen it firsthand. Some of the meetings in which he has supported a resident proposing an accessory unit have ended in screaming matches. In one extreme case, he said, a woman who proposed a unit in a Western Massachusetts town moved after a public meeting over her proposal spiraled out of control.

Contentious meetings aside, said Lee, the approval process can be lengthy and cost $10,000 or more. And then there are restrictions that supporters say are mostly arbitrary — exorbitant lot size requirements, aesthetic limitations, and strict parking space thresholds.


“In some of these towns, they’re legal, but I’d say just barely,” said Lee, whose company built Mary Casey’s ADU. “Everything is working against these homeowners, to the point where most people just don’t want to go through the trouble. It’s a shame, because the need for these units is immense.”

To be sure, the local restrictions are not only the result of resident protests. In many cases, Dain said, towns simply lack the time and resources to invest in changing their zoning laws. A state law would eliminate that burden, she said, while still giving municipalities some flexibility to set reasonable restrictions.

“There’s certainly reasonable regulations communities could come up with,” said Brendan Crighton, a state senator from Lynn who proposed the statewide legalization measure. “But to the same end, this is an urgent crisis we’re dealing with, and we need to start getting units available as quickly as possible. The local approach simply isn’t working.”

There are a few exceptions. A handful of Boston-area suburbs, and several towns in Western Massachusetts and on Cape Cod, have more broadly permitted ADUs. But it’s slow-going. It took advocates on the Cape roughly three years and a housing pinch that was hammering longtime residents to convince 12 of the 15 towns there to allow the units.

Now, as home prices in Greater Boston reach a record of $900,000 and the state lags more than 100,000 units behind current demand, advocates say ADU legislation can no longer be an afterthought.


“The Cape had to reach an absolute crisis level before we could convince people there was a real need for this,” said Alisa Magnotta, CEO of Cape Cod’s Housing Assistance Corporation, a local advocacy group. “I hope we can be a lesson for the rest of the state. We have to get our head out of the sand before this gets worse.”

Mary Casey, 90, outside of the accessory dwelling unit she lives in that is attached to her son’s Abington home.John Tlumacki/Globe Staff

Andrew Brinker can be reached at Follow him @andrewnbrinker.