Do you need a permit for a detached garage in Montgomery County, MD?
Yes. Every accessory structure needs a building permit in Montgomery County.
Rules last checked by a person on October 20, 2026. Guidance only; confirm with Montgomery County before you build.
Check your exact lot
Setbacks depend on your zoning district, and a flood zone can change the permit answer. Enter your address to see both.
Permits a detached garage can need in Montgomery County
| Permit | When it applies |
|---|---|
| Building permit | Every accessory structure needs a building permit in Montgomery County. |
| Floodplain development permit | If the lot is in a FEMA special flood hazard area, all development there needs a permit. |
| Electrical permit | Wiring needs its own permit.Confidence: medium |
R-60 Residential, one-family detached
| Location | Rear yard only, at least 60 ft from the front line |
|---|---|
| Side setback | 5 ft |
| Rear setback | 5 ft (10 ft on some corner lots) |
| Height | 20 ft to the highest point |
| Footprint | 50% of the house footprint or 600 sq ft, whichever is greater |
| Long or tall structures | +2 ft of setback per 2 ft of length over 24 ft, and per 1 ft of height over 15 ft |
R-90 Residential, one-family detached
| Location | Rear yard only, at least 60 ft from the front line |
|---|---|
| Side setback | 5 ft |
| Rear setback | 5 ft |
| Height | 20 ft to the highest point |
| Footprint | 50% of the house footprint or 600 sq ft, whichever is greater |
Local details
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
How to apply
- DPS eServices
- Department of Permitting Services
- MCAtlas zoning map
- Phone: 311 (240-777-0311)
Questions people ask
- When does a detached garage need a building permit in Montgomery County?
- Every accessory structure needs a building permit in Montgomery County.
- How far from the property line can a detached garage go in Montgomery County?
- Side setback: 5 ft. Setbacks vary by zoning district; check your exact lot for the district that applies.
- Where do I apply for a detached garage permit in Montgomery County?
- Apply through DPS eServices, or call 311 (240-777-0311).
Sources
- Montgomery County DPS, Building Permit Guidelines for Sheds in Residential Zones (rev. 7/14/2026). Checked 2026-10-19.
A building permit is required to install or construct any shed in Montgomery County... Regardless of its size, a shed must comply with the zoning ordinance for accessory structure setbacks and location.
- Montgomery County DPS, Permits Required / No Permits Required (2024). Checked 2026-10-19.
Retaining walls not over 48 inches in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge.
- 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19.
Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
- 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19.
Require permits for all proposed construction or other development in the community...
- 2024 IRC R105.2, Work exempt from permit (text published by the City of Benson, AZ). Checked 2026-10-19.
One-story detached accessory structures, provided that the floor area does not exceed 200 square feet. Fences not over 7 feet high. Decks not exceeding 200 square feet in area, that are not more than 30 inches above grade at any point, are not attached to a…