Montgomery County, MD · Montgomery County Zoning Ordinance (Chapter 59)
Retained residential floating zone under Article 59-8 (Div 8.2). Townhouse zone at a maximum density of 12.5 dwelling units per acre of usable area. These zones remain on the map from the pre-2014 ordinance and cannot be newly applied; development proceeds under Article 59-8 standards. Site plan approval is required (Sec 7.3.4).
Development standards in RT-12.5
Front setback
25 ft
Section 8.2.4
Rear setback
20 ft
Section 8.2.4
Side setback
At least 10 ft from an abutting lot for an end unit; where the side lot line of an end unit abuts a public street, the side setback must equal the required front setback — see Section 8.2.4
Side setback is banded in the ordinance — it depends on what you build or on the lot itself, so no single figure is true for the whole zone. The cited table is the authority; read the tier that matches your intended structure.
Read from Montgomery County Zoning Ordinance (Chapter 59), effective through 2026-02-03. Amendments adopted after that date (most recent 2026-04-13) are not yet reflected.
How complete is this market? Across 304,119 parcels we answer 60.0% of the 6 questions this site is built to answer, each with a source you can check. The rest are shown as “not recorded” rather than filled in — we would rather be short than wrong.
Permitted uses in RT-12.5
AllowedTownhouse Permitted uses for this zone are established by the Use Table for the RT and R-H Zones (Sec 8.2.3), within Chapter 59 Div 8.2.
AllowedSingle-Family Detached House Sec 3.3.1.B
AllowedTwo-Unit Living / Duplex Sec 3.3.1.C
AllowedMulti-Unit Living One-household attached units; max 40% of total units (Sec 8.2.3.B fn3)
"Conditional" means the use generally requires a public hearing or special-exception approval — a very different timeline and risk profile from a by-right permit.
This is the zone. What about the parcel?
Zone rules are the starting point — the answer for a specific property also depends on lot
size, overlays, existing improvements and site conditions. Run a free address lookup to see
what applies to one property.
Standards as recorded by Zonescore: Chapter 59 Art 59-8, Sec 8.2.4 (Table 8.2.4B), PDF (Feb 3 2026)
Coverage note: our ordinance review for this jurisdiction is still in progress. Treat the values above as a starting point and confirm against the ordinance before relying on them.