2023 Affordable Housing Overlay FAQ

“[Affordable housing] would mean the world to my family. We can have stability. We would have our own space instead of sharing a room.

More than 21,000 people are waiting for a home they can afford in Cambridge, but the city still isn’t building enough.

In October 2020, the City Council adopted a 100% Affordable Housing Zoning Overlay, removing certain barriers to the production of affordable housing. It has helped, but not enough - the city is still falling significantly short of its goals and our needs.

Now, in 2023, four City Councillors have proposed amendments to the AHO. These amendments would expand and strengthen the AHO by making more sites across the city available for affordable housing, and increasing the allowed density of affordable housing on those sites. However, they have been met with strong opposition from “not in my back-yard” voices. The City Council needs to hear your support.

Please join us in demanding more affordable housing in Cambridge. Sign and share our petition, email City Council, and see the ’help' section below for more ways you can help.

Why is housing so unaffordable in Cambridge?

Cambridge’s population has grown much faster than its supply of housing, especially affordable housing. The primary culprit? Our zoning laws – layers of inequitable restrictions, accumulated over decades, that severely limit where housing can be built in our city. This has caused our housing supply to fall ever further behind our needs and has caused rents to skyrocket. The Cambridge housing market has become a cruel game of musical chairs, with those least able to afford rent getting pushed out. 

What is “affordable housing”? How is it built?

As an initial step, in 1998, Cambridge started requiring larger new housing developments to set below-market rents for 10%, and later 20%, of their homes. Because this applies only to buildings of at least 10 homes or 10,000 square feet, and because the zoning code strongly disfavors multi-family housing, this provision alone cannot solve our affordable housing deficit. 


The shortage has begun to impact households in the middle income range, but people in the lower ranges have (as usual) borne the brunt of this problem. Federal and state governments consider a housing unit “affordable” when it costs no more than 30% of the income of households making average incomes. Cambridge also has a huge shortage of deeply affordable housing, sometimes defined as affordable to households making 30% of the average income. The Cambridge Housing Authority primarily provides deeply affordable housing in Cambridge. ABC members have consistently advocated for large increases to the budget for deeply affordable housing in Cambridge, along with tenant protections and zoning changes.


For affordable housing, Tthe city has sought to swiftly and efficiently meet the urgent need for such housing by providing limited relief from some zoning restrictions for new developments of only affordable units, a permanent condition enforceable through deed restrictions.  


After years of extensive public debate, Council and Committee hearings, informational sessions organized by citywide groups and neighborhood associations, and about a dozen presentations/Q&A sessions led by the Community Development Department at locations across the city, the 2020 City Council found that our restrictive and exclusionary zoning regime was not meeting the city’s needs. They enacted a group of zoning amendments known as the 100% Affordable Housing Overlay (AHO, more details below). 


Members of A Better Cambridge believe that the 100% Affordable Housing Overlay put us on the right path, and now we need to right-size the overlay to properly address our need for affordable housing. Four City Councilors believe so, too, and have proposed a package of amendments that will expand and strengthen the 100% Affordable Housing Overlay (more details below).

We ask that you join us to help reduce the housing crisis that now afflicts Cambridge (see 'help' section below).  

How will the 100% Affordable Housing Overlay amendments change zoning law?

The amendments proposed by four Councilors would allow: 

  • More affordable housing in all parts of Cambridgetaller buildings – specifically, the amendments allow up to 13 stories of affordable housing by-right along “AHO corridors,” a set of listed streets spanning the city, including Mass Ave, Mem Drive, Cambridge St., Mt. Auburn St, and others. This would allow affordable housing proposals like 2072 Mass Ave, which most councilors supported, to succeed, and would ensure that every neighborhood of the city has sites where affordable housing can be built at sufficient scale to be financially viable.
  • Taller buildings in "AHO squares" – specifically, up to 25 stories of affordable housing by-right in Central, Harvard and, Porter Squares as well as, and the "Webster Square" auto-shop area near the new Union Square T station. This would allow significantly more transit-oriented affordable housing like the Manning Apartments.
  • Greater flexibility to encourage more open space. AHO proposals that provide more-than-required open space would be allowed to take their sacrificed building bulk and put it into increased height. This provision would have allowed more housing for the formerly homeless to be built at 116 Norfolk St, and could have improved the site plan of Jefferson Park.

Map showing envisioned “AHO corridors” (solid black lines) and “AHO squares” (shaded areas).