Do you need a permit for a retaining wall in Fairfax County, VA?
It depends on the details of your project.
Fairfax treats walls like fences for height: 4 ft in a front yard, 7 ft in side and rear yards.
On marine clay, any new wall or grading needs a geotechnical engineer's soil report.
Regrading more than 2,500 sq ft needs a grading plan.
A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Fairfax County before you build.
Check your exact lot
Your zoning district sets the setbacks, and a flood zone can change the permit answer. Enter your address to see both.
Permits a retaining wall can need in Fairfax County
| Permit | When it applies |
|---|---|
| Grading plan (LDS) | Regrading more than 2,500 sq ft, or cutting or filling more than 18 in, needs an approved grading plan. |
| Architectural Review Board approval | This wall needs a building permit, and in a Historic Overlay District the Architectural Review Board (or Heritage Resources staff, for an accessory structure not visible from a historic property or major road) must approve it before the permit issues (Zoning Ordinance § 3101.6.C). |
| Building permit | Virginia exempts only retaining walls holding back less than 3 ft of unbalanced fill with no surcharge (USBC 108.2 item 7). |
| Floodplain development permit | Grading and walls in a FEMA special flood hazard area need a permit. |
| Chesapeake Bay (RPA) review | Any development or land disturbance in a Resource Protection Area generally needs county approval first. Sheds, garages, pools, gazebos and patios there need an exception with a public hearing. Some new decks can get an administrative waiver. |
| Geotechnical (soils) report | On mapped marine clay the Problem Soils Ordinance requires a soil report by a geotechnical engineer, with a slope stability analysis, for new construction and grading. |
Limits that apply citywide
| Wall height in a front yard | 4 ft |
|---|---|
| Wall height in side and rear yards | 7 ft |
| Corner lots | Nothing between 3.5 ft and 10 ft above street grade inside the 30 ft sight triangle |
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
Common questions
- When does a retaining wall need a building permit in Fairfax County?
- Virginia exempts only retaining walls holding back less than 3 ft of unbalanced fill with no surcharge (USBC 108.2 item 7). A retaining wall holding back less than 3 ft of soil, with nothing heavy above it, is exempt anywhere in Virginia.
- Where do I apply for a retaining wall permit in Fairfax County?
- Apply through PLUS permitting portal, or call 703-222-0801.
Sources
- Fairfax County Zoning Ordinance § 5104 (grading) and § 5105 (floodplain). Checked 2026-10-21
Sod and soil may be removed from or added to any lot to a depth of not more 18 inches without approval of a grading plan if the total disturbed area is 2,500 square feet or less... [Floodplain] major fill includes any fill, regardless of amount, in an area …
- Fairfax County Zoning Ordinance § 3101.6.C, Historic Overlay Districts: building permits (enCodePlus). Checked 2026-10-23
(1) ARB review and approval is required before the issuance of a building permit by the Director and approval of a sign permit by the Zoning Administrator, as listed below... ARB review and approval is not required for building permits that are only for the…
- Virginia USBC, 13VAC5-63-80 Section 108.2, Exemptions from application for permit. Checked 2026-10-23
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…
- 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...
- Virginia Chesapeake Bay Preservation Area Designation and Management Regulations (9VAC25-830-80, -140). Checked 2026-10-21
Land development may be allowed in the Resource Protection Area, subject to approval by the local government, only if it [is water dependent, is redevelopment, or fits the other listed cases]... The 100-foot wide buffer area shall be the landward component …
- Fairfax County LDS, FAQs on Resource Protection Areas (Chesapeake Bay Preservation Ordinance, Chapter 118). Checked 2026-10-21
Any development, land disturbing activity or other use within an RPA generally requires prior approval from the county... [Fences are allowed without an exception if they don't block surface flow or remove trees; sheds, detached garages, pools, gazebos and …
- Fairfax County LDS, Homeowner's Guide to Marine Clay. Checked 2026-10-21
Under the Problem Soils Ordinance (Chapter 107), a soil report prepared by a qualified geotechnical engineer is required for new construction and grading work in marine clay areas... Footings in marine clay must be at least 4 feet deep... A building permit …
- 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-…
- Fairfax County Zoning Ordinance § 5100.2.D, setback regulations (corner lots, sight distance, permitted extensions). Checked 2026-10-21
[Sight distance] Points must be 30 feet from the property lines extended... Sight distance must be maintained between two horizontal planes, one of which is three and one-half feet, and the other ten feet above the established grade... [Extensions] heating,…