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Do I need a permit? in Fairfax County, VA

Virginia's statewide code sets Fairfax's building-permit exemptions: sheds up to 256 sq ft, fences of any height (except pool barriers), masonry walls up to 6 ft, retaining walls holding back less than 3 ft, small shallow pools and like-for-like electric HVAC swaps. Every deck needs a permit. Zoning and grading rules still apply.

A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Fairfax County before you build.

The details

  • No building permit: one-story detached sheds and playhouses up to 256 sq ft. Fences of any height unless they are a pool barrier. Concrete or masonry walls up to 6 ft.High confidence
  • No building permit: retaining walls supporting less than 3 ft of soil with no surcharge. Pools of 150 sq ft or less under 24 in deep. Replacing an electric HVAC appliance in a house.High confidence
  • Always a permit: decks, additions, pool barriers, solar, Level 2 EV chargers and anything gas-fired.High confidence
  • Disturbing more than 2,500 sq ft, or cutting or filling more than 18 in, needs a grading or conservation plan from Land Development Services even when no building permit is needed.High confidence
  • In a flood hazard area the building official may require a permit for any of the exempt items.High confidence

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Common questions

Which small projects need no permit in Fairfax County?
Virginia's statewide code sets Fairfax's building-permit exemptions: sheds up to 256 sq ft, fences of any height (except pool barriers), masonry walls up to 6 ft, retaining walls holding back less than 3 ft, small shallow pools and like-for-like electric HVAC swaps. Every deck needs a permit. Zoning and grading rules still apply.

Sources

  1. Virginia USBC, 13VAC5-63-80 Section 108.2 (pools, mechanical, electrical and flood-area items). Checked 2026-10-21
    8. Swimming pools that have a surface area not greater than 150 square feet and are less than 24 inches deep... 14.4 Replacement of mechanical appliances provided the equipment is not fueled by gas or oil in Group R-2 where serving a single-family dwelling …
  2. 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 …

Disclaimer: This is general information, not legal or professional advice for any one property. Codes change. SetbackIQ is not a zoning determination, a permit, or a survey, and it does not replace an architect, engineer, or lawyer. Confirm with your building and zoning offices before you build, buy, or sign a contract.