Overview
Worth knowing
- Historic district deed covenants override zoning: Back Bay 1870s deed restrictions on setback (20-22-25 ft by street) codified into zoning but differ from Article 13 uniform 20 ft standard — ambiguity in variance/appeal cases.
- Boston Common Shadow Law: downtown heights capped by statute preventing shadows on Boston Common beyond specified times — regulatory ceiling independent of zoning FAR/height.
- Boston exempt from MBTA Communities Act (Section 3A) despite being MBTA hub — retains full local control over density near transit. Inclusionary Zoning (17-20%) is purely local policy.
+ 4 more in Quirks & notes
Districts
res_sf 2res_mf 2com 2ind 2cbd 1
| Code | Name | Category | Min lot | Height | Coverage | FAR | Du/ac | Parking | Setbacks F/S/R |
|---|---|---|---|---|---|---|---|---|---|
| R1 | Single-Family Residential | res_sf | 5,000 sf[1] | 35 ft[2] | 0.4[3] | 0.5[4] | — | — | — / — / — |
| R2 | Two-Family / Small Multifamily | res_sf | 5,000 sf[5] | 35 ft[6] | 0.5[7] | 1[8] | — | — | — / — / — |
| R3-R5 | Multifamily High-Density Urban | res_mf | — | 55 ft[9] | 0.6[10] | 2[11] | — | — | — / — / — |
| R6-R8 | Urban Residential / Apartment | res_mf | — | — | — | 4[12] | — | — | — / — / — |
| C1 | Neighborhood Commercial | com | — | 45 ft[13] | 0.6[14] | 1.5[15] | — | — | — / — / — |
| C2 | Local Commercial | com | — | — | 0.7[16] | 2.5[17] | — | — | — / — / — |
| C3-C5 | Downtown / High-Density Commercial | cbd | — | — | — | 6[18] | — | — | — / — / — |
| I-1 | Light Manufacturing | ind | — | 55 ft[19] | — | 1.5[20] | — | — | — / — / — |
| I-2 | Manufacturing | ind | — | 65 ft[21] | — | 1.5[22] | — | — | — / — / — |
Confidence: confirmed partial under review not found
Overlays
BHAC
Historic Beacon Hill District
HPBeacon Hill neighborhood; established 1955 (expanded 1958, 1963, 1975, 2024)
| review | Beacon Hill Architectural Commission (BHAC) review |
|---|---|
| scope | All exterior work visible from public way |
| views | Boston Common, Public Garden, Storrow Drive, Esplanade |
BBAC
Back Bay Historic District
HPBack Bay neighborhood; established 1966 (expanded 1974, 1979, 1981)
| review | Back Bay Architectural Commission (BBAC) / Boston Landmarks Commission review |
|---|---|
| scope | Height, setback, materials, fenestration |
| setbacks | 20 ft front yard (east-west streets); 22 ft (Marlborough, Newbury — deed covenants); 25 ft south Boylston |
CFROD
Coastal Flood Resilience Overlay District
FPAreas subject to 1% chance storm event + 40 in sea level rise (2070 baseline); extends beyond FEMA flood maps
| standard | Buildings must be adapted to withstand flooding, limit damage, prevent displacement |
|---|---|
| historic_exemption | Properties on National Register or designated by BLC may receive variance |
| adoption | 2021 |
SKY
Skyline District — Primary
DTDowntown Boston from Harbor to Boston Common, Washington St to Government Center
| max_height_ft | 700 |
|---|---|
| height_note | FAA flight path limited; Boston Common shadow law applies |
| far | unresolved |
SKY-LOW
Skyline District — Low
DTDowntown Boston — historic-sensitive areas
| max_height_ft | 155 |
|---|---|
| far | unresolved |
SKY-LOW-DT
Skyline District — Low Downtown Historic
DTWashington Street corridor
| max_height_ft | 155 |
|---|---|
| height_cap_non_residential | 200 ft cap for projects with <60% residential GFA |
WF
Waterfront / Harborpark Districts
SPDBoston waterfront areas; Harborpark established by state legislation
| note | Fragmented across multiple articles; detailed KPIs unresolved |
|---|
ND
Neighborhood Districts
SPDMajor neighborhoods: Roxbury (Art 50), East Boston (Art 53), North End (Art 54), South End (Art 64), South Boston (Art 68)
| roxbury_eda_height_ft | 65 |
|---|---|
| roxbury_eda_far | 2.0 |
| dudley_square_height_ft | 55 |
| dudley_square_far | 2.0 |
| community_facilities_height_ft | 45 |
| community_facilities_far | 2.0 |
| walnut_ave_height_ft | 35 |
| walnut_ave_far | 1.0 |
BT
Bulfinch Triangle District
SPDBulfinch Triangle area, downtown
| height_ft_range | 80-100 |
|---|---|
| far_range | 6-7 |
| note | Special conditions apply for 100 ft / FAR 7 |
IZ
Inclusionary Zoning Policy
AHMarket-rate projects of 7+ units needing zoning relief
| threshold | 7+ units (lowered from 10, Oct 2024) |
|---|---|
| affordability_pct | 17-20% (increased from 13%) |
| ami_target | 50-60% AMI average (deepened from 70%) |
| voucher_set_aside | 3% of large rental projects for mobile housing vouchers |
| alternative | Developers may pay into Inclusionary Development Policy Fund |
Adopted building codes
Statewide w/ amendments
Click a code label to open its state-by-state adoption atlas.
Quirks & notes
- Historic district deed covenants override zoning: Back Bay 1870s deed restrictions on setback (20-22-25 ft by street) codified into zoning but differ from Article 13 uniform 20 ft standard — ambiguity in variance/appeal cases.
- Boston Common Shadow Law: downtown heights capped by statute preventing shadows on Boston Common beyond specified times — regulatory ceiling independent of zoning FAR/height.
- Boston exempt from MBTA Communities Act (Section 3A) despite being MBTA hub — retains full local control over density near transit. Inclusionary Zoning (17-20%) is purely local policy.
- Waterfront zoning fragmented across Articles 40-42, 42A-42F (Harborpark), Article 25A (Coastal Flood), plus neighborhood district waterfront subdistricts — no single unified waterfront code.
- Historic structures on National Register may receive variance from Coastal Flood Resilience Overlay — potential conflict between flood resilience and preservation goals.
- Downtown Skyline Districts (2024) represent major departure from traditional C-zoning — transition period (2024-2025) creates uncertainty re: which provisions apply.
- Individual neighborhood districts (Articles 50-75) contain multiple subdistricts with varying dimensional requirements — zoning compliance requires precise subdistrict mapping.
Formulas
Definitions
- height
- Maximum building height in feet. Article 16. FAA flight path limits apply downtown (Skyline Districts). Boston Common shadow law also caps downtown heights by statute.
- lot_coverage
- Building footprint / lot area. Article 13.
- far
- Gross floor area / lot area. Primary density control. Article 13.
- du_ac
- impervious_cover
- setback_front
- Front property line to nearest building face. Article 13. Back Bay/Beacon Hill have deed-based setbacks (20-25 ft by street).
- setback_side
- Side property line to nearest building face. Article 13.
- setback_rear
- Rear property line to nearest building face. Article 13.
- parking
- Varies by district and use.
Capacity calculations
- max_footprint_sf
lot_area_sf * lot_coverage- max_gfa_sf
lot_area_sf * far- parking_required
units * parking
Massing explorer
Interactive 3D comparison across every district. Drag to orbit, scroll to zoom, use the slider to walk districts, and toggle applicable overlays in the right-side panel.
Sort by
Max height
— ft
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Floor area ratio
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Lot coverage
—%
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Setbacks (F / S / R)
— ft
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Parking
— /unit
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Max density
— du/ac
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Min lot size
— sf
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Copy zoning profile
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| District | Category | Height | FAR | Coverage | Setbacks | Parking | Density | Min lot | Overlays |
|---|
Sources & references
Citations
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Research status
Data quality
35%completeness18 confirmed15 partial28 inferred
Documented gaps
- Residential district (R1-R8) base KPIs largely inferred — Article 13 dimensional tables not fully extracted
- Commercial district (C1-C5) base KPIs inferred — require Article 13 full table
- Industrial FAR/height inferred — I-1/I-2 specific KPIs not confirmed
- Waterfront district dimensional controls (Articles 40-42) unresolved
- Skyline District FAR limits (SKY/SKY-LOW) unresolved
- Article 16 full height table not extracted
Known issues
schema:v1-legacypriority:lowdata:gaps-present
Other cities in this state
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