FAQs

Chapter 40B is a state law to facilitate the construction of low- or moderate-income housing. It establishes a local review and approval process where the Zoning Board of Appeals (ZBA) reviews housing projects that meet certain affordable housing requirements. For a project to qualify, at least 20% to 25% of the units must be set aside as long-term affordable housing for people with low or moderate incomes, while the remaining units are sold or rented at standard market rates. The remaining housing units in these developments are market rate. The law also sets a goal for every city and town to ensure that at least 10% of its total housing stock is affordable, a metric the state tracks using a list known as the Subsidized Housing Inventory (SHI).

Chapter 40B allows developers to bypass typical local zoning laws such as height or density, because they are providing a certain percentage of affordable housing units. The intention of allowing the bypass of local zoning laws is to increase the amount of affordable housing in cities that do not meet the 10% minimum on the SHI.  

The SHI is the master list used by the Massachusetts Executive Office of Housing and Livable Communities (EOHLC) to track how much affordable housing exists in each Massachusetts municipality. Not all affordable apartments make the list, as they must meet certain benchmarks. To be included in the SHI count, a unit must meet the following:

• It must be assisted by a federal or state housing program (like the Low Income Housing Tax Credit).   
• It must be reserved for households earning 80% or less of the Area Median Income (AMI).   
• There must be a legal document ensuring the unit stays affordable for a long period.
• The units must be filled with an open, fair lottery process.

The EOHLC typically releases a comprehensive statewide update every two years. The most recent major update was released in September 2025. Figures can change more frequently as municipalities submit new information regarding building permits, occupancy permits, or the expiration of affordability restrictions. To view the SHI yourself, please visit this link https://www.mass.gov/info-details/subsidized-housing-inventory-shi

According to the latest September 2025 SHI report from the state, Somerville has 3,228 qualified units. Based on the 2020 Census count of 36,167 total housing units, Somerville’s official SHI percentage is 8.93%.

Once the City of Somerville has reached the 10% threshold in Subsidized Housing Inventory, the local Zoning Board of Appeals will have more ability to approve or deny Chapter 40B project. The City may also choose to pursue more affordable housing to go beyond 10%.  

If a municipality has less than 10% of its year-round housing stock listed on the SHI, the state allows developers to bypass local zoning (like density or height limits) if the project is consistent with local needs. Once a town hits 10%, the ZBA has much more ability to deny a 40B project.

Yes, although Somerville does not reach 10% on the SHI, the City can still claim “Safe Harbor” under the following conditions: 

1. State law allows a town to claim "Safe Harbor" if at least 1.5% of its total land area is occupied by subsidized housing. In 2022, the City of Somerville calculated that 3.8% of its general land area was occupied by SHI units, meaning the City may meet the criteria for "Safe Harbor" despite being under 10% on the unit count. Therefore, the ZBA reserves the right to deny any 40B application or waiver that does not meet the City’s planning goals, or place conditions upon an application’s approval without risk of overturn upon appeal.
2. If a city increases its SHI units by at least 0.5% in a single year, it can earn a one-year "Safe Harbor" from 40B overrides.

“Safe Harbor” is a legal protection for a municipality. If a municipality meets the above benchmarks OR meets 10% on the SHI, it meets what is known as Statutory Minima. This grants the right to deny a developer's request for a 40B permit without the state stepping in to overturn that decision. 

• Project Eligibility Letter (PEL): The 40B comprehensive permit process begins with a PEL application submitted by a developer to one of four state agencies (MassHousing, MHP, DHCD, or MassDevelopment). Without a written Project Eligibility decision granted by one of these agencies, the developer cannot file a comprehensive permit application with the City of Somerville.
  
  
• Local Comment Period: After the developer has submitted their PEL application to the agency and the agency confirms it meets the submittal requirements, a 30-day review period begins where the City and community members can submit comments about the project. The agency controls the start, stop and any pauses of the comment period.
  
  
•  Subsidizing Agency Decision: After the local comment period closes, the agency will issue a letter to the developer, the City, and the Zoning Board of Appeals confirming the application has met all the 40B requirements and the agency’s policy goals. The agency will take time to make this decision.
  
  
• Comprehensive Permit Application (CPA): Once the developer receives the PEL decision, they will file for a Comprehensive Permit Application through the Zoning Board of Appeals.
  
  
• ZBA Review:
  1. Within 7 days of the CPA filing date, the ZBA must distribute the application to local boards/committees/departments.
      
  2. Within 30 days of the CPA filing date, the ZBA must open a public hearing 
     
     
• Safe Harbor Window: Within 15 days following the initial public hearing, the ZBA must give written notice to Copper Mill and Mass Housing if it intends claim Safe Harbor. Safe Harbor means the ZBA can deny the 40B application or approve it with conditions without being overturned by the state because the municipality has already met certain affordable housing goals.
  
  
  1. Within 15 days: if the ZBA claims Safe Harbor, the developer may appeal with written notice to the agency and the ZBA.
     
     
  2. Within 30 days: if the developer files an appeal, the agency must issue a decision concerning Safe Harbor.
      
  3. Within 20 days: The developer or the ZBA may appeal the decision to the Housing Appeals Committee (HAC) and the public hearing must stay open until the appeal is decided.
     
     
• Public Hearing Close: Within 180 days from the opening of the public hearing, the ZBA must close the hearing unless the applicant agrees to an extension in writing.
   
• ZBA Decision: Within 40 days from the close of the public hearing, the ZBA must come to a decision and file it with the municipal clerk.
   
• Opportunity to File an Appeal: Within 20 days from the decision filing, the applicant can file an appeal with the HAC if the ZBA denies the permit OR if the terms and conditions of the permit are unsatisfactory.

• Final Approval Application: If a comprehensive permit is approved, and no appeal is filed within the deadline, the developer must submit a Final Approval Application to the agency.
  
  
• Construction: When the Final Approval Application is approved by the agency, the developer must complete the following: prepare architectural and engineering plans, apply for a building permit with the municipality, and meet all pre-agreed conditions. 

For developers, entry into the comprehensive permit process begins with a Project Eligibility Letter application to one of the subsidizing agencies. The application forms differ by agency, but all of them include these basic components: 

1. Site location and description
2. A locus map and photographs of the surrounding area
3. The proposed buildings and approximate number units by size (number of bedrooms, floor area) and type (ownership or rental) 
4. The name of the housing program under which a Project Eligibility determination is sought
5. Preliminary development pro forma
6. Relevant project details, such as the percentage of low- or moderate-income units, income eligibility standards, the duration of the proposed affordable housing restrictions, and whether the applicant is a non-profit, public agency, or limited dividend organization
7. Conceptual site plan, elevation drawings, and basic site development calculations, e.g., approximate impervious coverage, approximate open areas, number of parking spaces, and average parking spaces per unit
8. Description of the approach to architectural massing and exterior building materials, and how the proposed buildings relate to adjacent properties
9. A list of proposed waivers of zoning requirements and all other relevant local bylaws, ordinances, and regulations
10. and Evidence of control of the site (usually a purchase and sale agreement or deed).

No. While 40B can waive local zoning, it cannot waive state or federal laws, such as the Wetlands Protection Act, state building and fire codes.