Setbacks & Height Limits in Boston

This guide explains how setback and height rules work in Boston. Unlike most US cities, Boston does not have a single citywide schedule of dimensional regulations. Instead, the Boston Zoning Code is organized by neighborhood, with each article setting its own yard, height, FAR, and open space standards. Always confirm with the Boston Planning Department (BPDA) and the specific neighborhood article that governs your parcel.

What Are Setbacks?

A setback (also called a "yard" in the Boston Zoning Code) is the minimum required distance between a building and a lot line. Setbacks are measured from the property line to the nearest point of the building wall. Boston's code defines separate front yard, side yard, and rear yard requirements for each subdistrict, with corner lots treated as having two front yards (one per street frontage).

In many of Boston's older, denser neighborhoods, the required front yard is simply the average of existing buildings on the block — meaning your "setback" depends on what your neighbors already built.

Typical Residential Setbacks (1F Subdistrict Example)

For a representative 1F (One-Family Residential) subdistrict in an outer neighborhood such as West Roxbury or Hyde Park, expect approximately:

A 3F (Three-Family) subdistrict in a denser neighborhood such as Dorchester or Jamaica Plain is typically much tighter — front yards of 0 to 10 ft, side yards of 0 to 5 ft, and rear yards of 15 to 25 ft, often expressed as a percentage of lot depth. Row-house and downtown districts allow zero-lot-line construction on shared party walls.

These are representative values only. Your exact subdistrict may set different numbers.

Height Limits

Maximum building height in Boston residential subdistricts is typically:

• 1F and 2F subdistricts — around 35 ft, measured from grade to the highest point of a pitched roof or to the top of a flat roof parapet
• 3F subdistricts — typically 35 to 40 ft
• MFR (Multi-Family) subdistricts — typically 45 to 55 ft, depending on the neighborhood article
• Downtown, Seaport, and Back Bay mixed-use districts — substantially higher, often governed by FAR caps and Article 80 large-project review rather than a simple height number

Height rules get more complicated in:

• Landmark and historic districts — Back Bay, Beacon Hill, South End, and Bay Village have strict design review that can cap height below the zoning number
• Greenbelt Protection Overlay District — additional height constraints along parkways
• Logan Airport overlay — FAA and Massport height restrictions in East Boston
• Coastal Flood Resilience Overlay — may require raising grade, which interacts with height measurement
• Planned Development Areas (PDAs) — negotiated height through Article 80 review

Lot Coverage, FAR, and Useable Open Space

Boston controls building bulk primarily through three numbers:

• Floor Area Ratio (FAR) — total floor area divided by lot area. 1F subdistricts typically cap FAR around 0.5 to 0.8; 3F subdistricts around 0.8 to 1.5; denser MFR and mixed-use around 2.0 or higher.
• Useable Open Space — a minimum square-foot requirement per dwelling unit, often 300 to 800 sq ft depending on subdistrict
• Lot coverage — used in some neighborhood articles, typically 40% to 60% in residential subdistricts

A FAR of 0.8 on a 5,000 sq ft lot allows 4,000 sq ft of above-grade floor area.

Neighborhood-Specific Articles

The Boston Zoning Code is organized by neighborhood article. The dimensional table you need depends on which article covers your parcel. Key examples:

• Article 51 — Allston-Brighton
• Article 53 — Roxbury
• Article 55 — Dorchester
• Article 56 — East Boston
• Article 59 — Jamaica Plain
• Article 60 — Hyde Park
• Article 65 — South Boston
• Article 66 — Charlestown
• Article 67 — Roslindale
• Article 69 — West Roxbury

Downtown, Back Bay, and the Seaport are covered by separate articles (Article 38 Back Bay, Article 43 Central Business District, Article 42A Harborpark, etc.). Each article contains its own subdistrict list and dimensional table. Always start by confirming which article governs your address through the BPDA's zoning viewer.

Common Exceptions and Encroachments

Boston's zoning articles generally allow these projections into required yards:

• Eaves, cornices, and gutters — up to 2 ft
• Chimneys — up to 2 ft
• Uncovered porches, stoops, and front steps
• Bay windows — limited projection, often 3 ft
• Mechanical equipment (HVAC condensers) subject to noise rules

Fences, retaining walls, decks, and accessory structures have separate rules — check the accessory structure section of your neighborhood article.

State ADU Overrides

If your project is an Accessory Dwelling Unit (ADU), the 2024 Massachusetts ADU law overrides local setback and height rules in single-family zones. ADUs up to 900 sq ft must be allowed by right, with reduced side/rear setbacks (typically 5 ft) and an ADU-specific height cap of about 20 ft. See the ADU rules page for Boston-specific details.

How to Look Up Your Specific Requirements

1. Find your neighborhood article — Boston's zoning code is organized by neighborhood, so step one is identifying which article covers your address
2. Find your subdistrict — use the Boston zoning map through the BPDA to identify your specific subdistrict (for example, 1F-5000 or 3F-4000)
3. Read the dimensional table in your article — each neighborhood article has a table listing yards, height, FAR, and open space by subdistrict
4. Check for overlays — Greenbelt Protection, Coastal Flood Resilience, Groundwater Conservation, and historic district overlays can modify base rules
5. Contact BPDA zoning staff — the BPDA offers zoning determinations before you commit to a design

Variances

If your project cannot meet the strict letter of the Boston Zoning Code, you may apply to the Zoning Board of Appeal (ZBA) for a variance or conditional use permit. Variances in Boston are common — the code's age and the city's irregular lot patterns mean many projects need some form of relief. See the Variance Application Guide for the general process.

Official Sources

See the sources linked in the frontmatter for the Boston Zoning Code on Municode and the BPDA planning department site. This guide is informational and is not a substitute for direct confirmation from BPDA zoning staff or a licensed Boston zoning attorney. Always verify setbacks, height, and FAR against the current text of your neighborhood article before finalizing design.