Montgomery County, MD Zoning Overlays & Bonuses: Density Bonus Law (2026)
Key Facts
- Zone code
- PD (Planned Development)
- MPDU threshold, under 28 du/ac
- Bonus units or 12.5%, whichever greater
- MPDU threshold, over 28 du/ac
- At least 12.5% of total units
- TDR density bonus cap
- Up to 10% above master plan density
- Governing section
- Montgomery County Code, Ch. 59 § 8.3.2
Summary
In the county's Planned Development (PD) zone, Chapter 59 lets projects exceed the maximum base density to build Moderately Priced Dwelling Units, with the required MPDU share set by how dense the project already is.
the maximum density allowed under Section 8.3.2.C.1 may be increased to accommodate the construction of MPDUs if: (a) the number of MPDUs for a project with a residential density of less than 28 dwelling units per acre is at least the number of bonus density units or 12.5% of the total number of dwelling units, whichever is greater; or (b) the number of MPDUs for a project with a residential density of more than 28 dwelling units per acre must be at least 12.5% of the total number of dwelling units under Chapter 25A;
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-90: Montgomery County Code contains legislation effective through May 7, 2026 | Zoning Updated Effective: April 13, 2026 | COMCOR Regulations effective as of July 1, 2026).
Full Breakdown
Montgomery County Code Chapter 59, Section 8.3.2 governs the Planned Development (PD) zone, one of the county's density-bonus tools for building Moderately Priced Dwelling Units (MPDUs) required under Chapter 25A. A project may exceed the PD zone's base density cap to add MPDUs: below 28 dwelling units per acre, MPDUs must equal the bonus units or 12.5% of total units, whichever is greater; above 28 units per acre, MPDUs must be at least 12.5% of the total. Separate PD provisions allow up to a 10% density bonus for approved transferable development rights (TDRs) and larger increases for senior housing.
Violations & Fines
Building above the base density cap without qualifying MPDU, TDR, or senior-housing findings is unauthorized construction, enforced by the Department of Permitting Services through permit denial or stop-work orders.
Frequently Asked Questions
Does this MPDU density bonus apply county-wide?
How much extra density can a PD project get for MPDUs?
Is this the same as the county's MPDU requirement itself?
Sources & Official References
Other rules in Montgomery County
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