Fairfax's Accessory Structures: The Rules That Matter

Every city handles accessory structures a little differently. In Fairfax, Virginia, there are 3 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Shed Rules

In the City of Fairfax, sheds under 256 square feet on residential lots typically do not require a building permit under the Virginia Uniform Statewide Building Code, but zoning approval is required. Sheds must meet rear and side setbacks, typically 5 to 10 feet, and cannot be placed in front yards. Electrical and plumbing work requires separate permits. HOA approval may be required.

Key details: Fact: Building permit exempt under 256 sq ft but zoning review required. Fact: Rear yard placement with 5 ft minimum side setback typical. Fact: Maximum accessory height usually 12 to 15 feet. Fact: Electrical or plumbing to shed requires separate permit. Fact: HOA approval often required in addition to city review.

Contact your local code enforcement office for specific penalty information.

Garage Conversions

Detached garages in the City of Fairfax require a building permit regardless of size and must comply with residential zoning setbacks. Typical rear setbacks are 5 to 10 feet and side setbacks 5 feet for R-1 and R-2 districts. Maximum height usually 15 to 20 feet. Lot coverage and floor area limits apply. Converting a garage to living space requires separate permits and ADU review if adding kitchen.

Key details: Fact: Building permit required for any detached garage regardless of size. Fact: Typical setbacks: 5 ft side, 5-10 ft rear in R-1/R-2. Fact: Maximum height usually 15 to 20 feet. Fact: Conversion to living space requires ADU review and permits. Fact: Electrical work requires separate permit and licensed installer.

Contact your local code enforcement office for specific penalty information.

ADU Rules

The City of Fairfax (independent city) currently allows Accessory Dwelling Units only as attached units within a single-family home under Zoning Ordinance §3.5.5.D.1. ADUs may not exceed 35% of the principal dwelling's size and may have no more than two bedrooms. Either the main or accessory unit must be owner-occupied. Detached ADUs are not currently permitted, and short-term rentals (Airbnb, etc.) are not allowed in the City.

Key details: Governing Section: Zoning Ordinance §3.5.5.D.1. Allowed Form: Attached only (within single-family home). Max Size: 35% of principal dwelling. Max Bedrooms: Two. Owner Occupancy: Required (main or accessory unit).

Constructing or occupying an ADU without zoning approval, exceeding the 35% size cap or two-bedroom limit, building a detached ADU, or violating the owner-occupancy requirement subjects the owner to zoning enforcement under the City Code and Zoning Ordinance, including stop-work orders, civil penalties, and required removal or modification of unpermitted improvements. Using an ADU as a short-term rental is also prohibited.

Compared to other cities, Fairfax takes a harder line on adu rules. The enforcement and penalty structure reflects that.

The Bottom Line

Fairfax's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Fairfax is broadly strict or permissive.

Keep in mind that Fairfax can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.