Boston Setbacks, Yards & Height Limits

Fact-checked against Boston's current zoning framework and Massachusetts' current ADU law on September 21, 2026.

Boston does not have one citywide residential setback-and-height schedule. Much of the Zoning Code remains organized through neighborhood articles and subdistricts, while newer Squares + Streets districts now apply in selected mapped areas.

Because of that structure, publishing a generic “1F = 15/10/20 ft” table is unsafe. The controlling dimensions must be taken from the article and subdistrict actually mapped on the parcel.

Neighborhood Articles Still Matter

Many Boston parcels remain governed by neighborhood-specific articles. Depending on location, the code can specify:

• front, side, and rear yards;
• maximum building height and stories;
• Floor Area Ratio (FAR);
• usable open space;
• lot area and frontage;
• contextual or existing-building setback rules.

Two parcels with superficially similar residential character can therefore have different dimensional standards because they are in different neighborhood articles or subdistricts.

The previous page's “representative” 1F and 3F setback numbers have been removed rather than presenting them as Boston-wide norms.

Squares + Streets Is Now Part of the Current Code

Boston adopted the first Squares + Streets zoning text in April 2024. The Zoning Commission adopted further text updates in December 2025, including two additional district options.

Squares + Streets districts are mapped only through separate neighborhood rezoning processes. They should not be applied to the whole city.

Where a parcel is inside a mapped Squares + Streets district, use the current Squares + Streets dimensional and form standards instead of an older neighborhood-residential shorthand.

Height Is Parcel- and District-Specific

Boston does not have a general rule that all one- and two-family districts are 35 ft or all three-family districts are 35–40 ft.

Height can depend on:

• the specific zoning subdistrict;
• mapped Squares + Streets zoning;
• Planned Development Areas;
• historic/landmark controls;
• airport and Massport constraints;
• Coastal Flood Resilience Overlay rules;
• Article 80 or other project-specific approvals.

Use the exact zoning article and map designation for the parcel.

FAR, Open Space, and Lot Dimensions

Boston commonly controls development with a combination of FAR, yards, usable open space, lot size, frontage, and height.

Do not infer a universal residential FAR or lot-coverage percentage from the building type alone.

Massachusetts State ADU Law

The previous page incorrectly stated that the 2024 Massachusetts ADU law itself creates “typically 5-ft setbacks” and “about a 20-ft height cap.”

The current statewide law works differently.

Effective February 2, 2025, Massachusetts requires one Protected Use ADU to be allowed by right in zoning districts where single-family homes are allowed. The statutory ADU is no larger than 900 sq ft or one-half the gross floor area of the principal dwelling, whichever is smaller.

Municipalities may still apply reasonable dimensional rules, including setbacks, bulk, height, and number of stories. Under the state regulations, those dimensional standards may not be more restrictive than the most permissive applicable standards for the principal dwelling, a single-family dwelling, or an accessory structure in the same district, and they must satisfy the state's reasonableness test.

The state law therefore does not impose one universal 5-ft setback or 20-ft height standard for Boston ADUs.

See the Boston ADU rules page for local implementation.

How to Check a Property

1. Find the parcel in Boston's official zoning viewer.
2. Identify the governing neighborhood article or mapped Squares + Streets district.
3. Identify the precise subdistrict and all overlays.
4. Read that article's dimensional table and footnotes.
5. Check historic, flood-resilience, airport, PDA, and other special controls.
6. For an ADU, apply Massachusetts Protected Use ADU law together with Boston's current dimensional standards.
7. Confirm project-specific interpretations with the Boston Planning Department / Inspectional Services Department.

Official Sources

• Boston Zoning Code
• Boston Planning — Squares + Streets Zoning Districts
• Massachusetts — Accessory Dwelling Units
• Massachusetts — ADU FAQs

This guide is informational only. The mapped Boston zoning article, current amendments, state law, and parcel-specific approvals control.