Do you need a permit for a detached garage in Fairfax County, VA?
It depends on size and placement.
Detached garages over 256 sq ft need a building permit.
A garage over 12 ft tall must sit at least its own height from the rear lot line.
Garages can't go in the front yard on lots of 36,000 sq ft or less.
Rules last checked by a person on October 20, 2026. Guidance only; confirm with Fairfax 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 Fairfax County
| Permit | When it applies |
|---|---|
| Building permit | Garages are almost always bigger than the 256 sq ft exemption, and attached garages always need a permit. |
| 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 |
Limits that apply citywide
| Location | Not in the front yard or the minimum front setback |
|---|---|
| 8 1/2 to 12 ft tall | 5 ft from the side and rear lot lines |
| Over 12 ft tall | Rear setback equal to its height; the district's minimum side setback |
| Height cap | 20 ft (lots of 36,000 sq ft or less) |
R-3 Residential, 3 dwellings per acre
| House setbacks | 30 ft front, 12 ft side, 25 ft rear, 35 ft height (cluster lots: 20 ft front, 8 ft side, 20 ft total) |
|---|
R-4 Residential, 4 dwellings per acre
| House setbacks | 30 ft front, 10 ft side, 25 ft rear, 35 ft height (cluster lots: 20 ft front, 8 ft side) |
|---|
R-5 Residential, 5 dwellings per acre
| House setbacks | 20 ft front, 8 ft side, 25 ft rear, 35 ft height |
|---|
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.
- Lots along streams may fall in a Chesapeake Bay Resource Protection Area. Any shed, deck or addition in an RPA needs Bay Act review before a permit can issue.
How to apply
Questions people ask
- When does a detached garage need a building permit in Fairfax County?
- Garages are almost always bigger than the 256 sq ft exemption, and attached garages always need a permit. Only one-story detached structures up to 256 sq ft are exempt.
- How far from the property line can a detached garage go in Fairfax County?
- House setbacks: 30 ft front, 12 ft side, 25 ft rear, 35 ft height (cluster lots: 20 ft front, 8 ft side, 20 ft total). Setbacks vary by zoning district; check your exact lot for the district that applies.
- Where do I apply for a detached garage permit in Fairfax County?
- Apply through PLUS permitting portal, or call 703-222-0801.
Sources
- Virginia USBC, 13VAC5-63-80 Section 108.2, Exemptions from application for permit. Checked 2026-10-20.
2. One story detached structures used as tool and storage sheds, playhouses, or similar uses, provided the building area does not exceed 256 square feet... 5. Fences of any height unless required for pedestrian safety as provided for by Section 3306 or used…
- Fairfax County Code Compliance, Building trade and unpermitted construction (September 2024). Checked 2026-10-20.
[Permits are often required for] decks, porches, sheds, and adding other detached structures exceeding 256 square feet.
- 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…
- Fairfax County Zoning Ordinance § 4102.7.A(6)-(7), freestanding accessory structures and fences. Checked 2026-10-20.
On a lot that is 36,000 square feet or less, accessory structures may not be located in the front yard... If the structure does not exceed eight and one-half feet in height, it may be located in any part of a side yard or rear yard... between eight and one-…