Cambridge's Affordable Housing Overlay

High Level Overview

The Affordable Housing Overlay passed in Cambridge provides for construction of 100% affordable four story apartment buildings anywhere in the city by-right, including in districts that currently have apartment bans. It entirely eliminates parking minimums, and generally attempts to eliminate or mitigate all zoning requirements that make it impractical to build apartments.

AHO Passed Into Law!

On October 5th, the Affordable Housing Overlay passed into law, allowing 100% affordable apartment buildings citywide.

We need more homes to support our low-income community.

Cambridge needs more homes to support its low and middle income community. In the face of our ongoing regional housing crisis, we need to do more to help ensure that we do whatever we can for our most vulnerable populations in Cambridge.

Unfortunately, with massive price increases for land in the city, the ability to purchase new property on which to build homes for these families has all but stopped in Cambridge. Market rate developers can outbid affordable housing developers every time, because the revenue they will generate in redeveloping the property gives them tremendous purchasing power, outstripping the resources of affordable housing non-profits.

To work to resolve that, the City has passed a change to the zoning code to allow housing developers a more relaxed set of rules on how large buildings can be -- if they create 100% affordable units.

The proposal opens up new potential for creating affordable housing units, at lower cost, throughout Cambridge.

Three Key Elements

There are three key elements to opening up this new potential for affordable housing developers to create homes citywide for low to middle-income households in Cambridge:

Residential Size Increase

Slightly increase the size of buildings allowed in residential areas citywide -- allowing 4 story buildings with minimal setbacks throughout all residential districts.

Taller Buildings on Corridors

Allow taller housing developments (up to 7 stories) along commercial corridors like Massachusetts Avenue and Cambridge Street.

Process Change

Developments are by-right, meaning the process is changed to eliminate costly citizen lawsuits which have been used to delay housing construction.


With these changes, we can reopen Cambridge to new affordable housing development citywide to support our families in need of housing today. By bringing land costs per unit back in line specifically for affordable development, we can expect to resume purchasing new properties to build on. With relaxed zoning citywide, we can open up parts of Cambridge that have previously been out of reach financially. In the end, the Affordable Housing Overlay is a tool to help get the city moving again on building new affordable housing across the city.

AHO Timeline

The affordable housing overlay has been making its way through the Council for 2 years, started by the Envision Cambridge process. see a timeline of meetings, votes, and discussions.

Latest Articles

One of the key reasons for the need of greater affordable housing opportunities citywide is that our historical zoning differences have led to a distribution of affordable housing which reflects inequality throughout our city. the Affordable Housing Overlay opens the door to changing that.

New homes don’t always mean new construction. The proposed 100% Affordable Housing Overlay will support more than just new construction, by relaxing zoning rules across the board. With relaxed zoning rules, it will be easier to create new homes in the existing buildings we have -- something made difficult or impossible by the restrictive zoning in the city today.

Under Cambridge's proposed Affordable Housing Overlay, affordable housing developments would be allowed to exceed the height allowed under current zoning in many districts. However, there's been a lot of misunderstanding of what this would look like in practice. To help give a sense of what these increase look like, here are some examples in context of their street to give a sense of what the allowed height increases could look like throughout Cambridge.

Have you heard from someone who is telling you about the overlay? There's a lot of misinformation going on at the moment: make sure you get the right info about what the overlay will and won't do in Cambridge.