MBTA Communities Zoning (Section 3A)

Section 3A of the Zoning Act (M.G.L. c. 40A), commonly called the MBTA Communities law, requires communities served by the MBTA to have at least one zoning district of reasonable size where multifamily housing is allowed by right.

The basic requirements

Under the law and the state’s implementing rules, the district generally must:

• allow multifamily housing by right, without a special permit or other discretionary approval;
• have a minimum gross density of 15 units per acre;
• be located within half a mile of a transit station, where the community has one;
• be suitable for families with children, with no age restrictions.

The required size and capacity of the district vary by community type. Deadlines for compliance were phased in by community type over several years. In January 2025, the Supreme Judicial Court upheld the law and its enforceability, and the state’s regulations were subsequently formalized.

What it means for property owners

If your property is in or near a compliant district, multifamily housing may now be allowed by right, often with site plan review. That can be a significant change in what the land can support. District boundaries, dimensional standards, and any affordability requirements are set locally, so the details matter.

What to check

• Whether your community has adopted a compliant district, and where its boundaries are.
• The district’s dimensional standards: height, setbacks, lot coverage, and parking.
• How site plan review applies in the district.

General information, not legal advice. Compliance status varies by community and changes over time.