Boston, MA Zoning Overlays & Bonuses: Density Bonus Law (2026)
Key Facts
- Bonus amount
- +1.0 floor area ratio
- Eligible areas
- PDA I, VI, VII, and X only
- Baseline FAR range
- 2.0 (PDA VII) to 5.0 (PDA VI)
- Mixed-use treatment
- Bonus pro-rated above ground floor
- Approval path
- Article 80 PDA Development Plan review
- Governing article
- Zoning Code Article 62, Charlestown District
Summary
Boston's Zoning Code grants a residential density bonus in the Charlestown Neighborhood District: Section 62-21 adds 1.0 to the maximum floor area ratio for residential projects in Planned Development Areas I, VI, VII, and X. Mixed-use buildings with non-residential floors above ground level get the bonus pro-rated. The baseline FAR these bonuses build on, set in Table 2, ranges from 2.0 to 5.0 depending on the PDA.
Section 62-21 - Residential Density Bonus for Planned Development Areas. Projects containing a residential use in PDA I, PDA VI, PDA VII, and PDA X are eligible for a 1.0 increase to the maximum FAR for the area.
For projects containing a mix of residential and non-residential uses above the ground floor, the residential FAR bonus is pro-rated according to the equation shown in this Section 62-21.
Full Breakdown
Boston zones Charlestown under Zoning Code Article 62, and Section 62-21 layers a residential density bonus onto the Planned Development Area (PDA) framework created by Section 62-20. Table 2 in Section 62-20 sets a baseline maximum floor area ratio for each of the ten Charlestown PDAs, ranging from 2.0 in PDA VII to 5.0 in PDA VI, along with maximum building heights and minimum permeable lot area. Section 62-21 then adds a 1.0 FAR increase, but only for projects with a residential use sited in PDA I, PDA VI, PDA VII, or PDA X.
That lifts the ceiling to 4.0 in PDA I and PDA X, 6.0 in PDA VI, and 3.0 in PDA VII. The remaining six PDAs in the district (II, III, IV, V, VIII, and IX) are not listed in Section 62-21 and receive no residential FAR bonus under this provision. Where a building combines residential space with non-residential uses above the ground floor, the bonus is not applied at the full 1.0 rate; instead it is pro-rated according to the equation set out in Section 62-21, scaling the extra floor area to the residential share of the upper floors.
Ground-floor retail or commercial space does not by itself reduce the bonus, since the pro-ration only reaches uses placed above the ground floor. The bonus is not self-executing: Section 62-22 requires that PDA Development Plans, PDA Master Plans, and Proposed Projects in these areas go through Article 80 Planned Development Area Review before a project can claim the extra FAR, which in practice means Boston Planning & Development Agency approval of a Development Plan that specifies the bonus square footage.
Violations & Fines
The density bonus is not a right that comes with a penalty structure; it is granted or withheld through project review. Section 62-22 channels every PDA Development Plan, Master Plan, and Proposed Project through Article 80 Large Project Review, so a developer who builds beyond the baseline FAR in Table 2 without an approved Development Plan reflecting the Section 62-21 bonus is building outside the as-of-right envelope and risks an Inspectional Services Department stop-work order or permit denial.
Frequently Asked Questions
Which Planned Development Areas get Boston's Charlestown density bonus?
Does a mixed-use building with ground-floor retail still qualify for the full 1.0 FAR bonus?
Who approves a project claiming the density bonus?
What is the baseline FAR before the bonus applies in these PDAs?
Sources & Official References
Other rules in Boston
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