Triple Deckers Legalized: A Review of the Data

In late 2023, Somerville City Council amended the Zoning Ordinance to allow triple deckers everywhere in the Neighborhood Residential (NR) zone, our base zoning district. Until then, they had been allowed only when adjacent to other triple deckers, and only if the third unit was subsidized, a requirement that made new construction impossible to finance. With recently obtained housing permitting data, we can now assess how these changes affected the housing supply in our city and how it compares to other types of changes going on in this zone. 

This chart shows the three primary types of changes that happened, and the effect on number of homes they had per year from 2020-2024:

We can clearly see that the creation of three-family homes was on its way out until the zoning change passed and boosted production. Worse, home builders sometimes opted to remove a home by converting 2-family buildings to singles. In fact, if it were not for the exceptional case of 20 new homes at 125 Lowell St, the entire NR zone would have been a net negative for the city’s housing supply in 2023. 

Today, we’re adding homes, which is great. But the scale of construction in NR is still paltry. NR covers 52% of the area of the city, has 69% of the homes, and averages 2.2 homes per lot. It’s close to maxed out under current zoning, and so we do not expect a significant number of triple deckers to actually be built in the coming years. Additionally, any construction creates noise, dust, street blockages, and so forth, without actually creating very many new homes. Wouldn’t it be great if all that impact actually resulted in a better outcome for the city? Can’t we do better?

Somerville YIMBY Shirts

Election Schedule Update

In mid-June, we sent our endorsement survey to all city council and mayoral candidates. We’ve asked for responses by July 25, and plan to announce endorsements in mid-August. Then we’ll need your help to support pro-housing candidates. We’ll be in touch soon with more opportunities to get involved.

Upcoming Events

City Council remains in recess for the next couple of weeks, but there are still several policy-related items on the calendar:

July 21: Mayoral Candidate Forum — Union Square Neighborhood Council presents a policy discussion among mayoral candidates. 6:30 to 8:30 pm in person at 8 Tyler Street and on Zoom.

August 5: Historic Commission Meeting — A homeowner requires city permission to install a new front door. 6:45 pm, via Zoom.

As always, you can find our Google calendar at somervilleyimby.org/calendar. If you notice we’ve missed an event, feel free to reply to this message and let us know!

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