ADU Pass
Fairfax
No County portion
Also in: Fairfax County
ADU Pass helps homeowners in Fairfax, No County, Virginia navigate the permit paperwork for building an accessory dwelling unit. This area covers 1 ZIP code.
Map
ADU details
ADU legality: allowed-with-restrictions
City of Fairfax allows only interior ADUs as of 2026. Detached ADUs prohibited pending Spring 2026 ordinance update. SHORT-TERM RENTALS (Airbnb, VRBO, etc.) are EXPLICITLY PROHIBITED city-wide; this materially affects ADU economics here versus surrounding Fairfax County.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 250 | $2,200 | $87,500 | $89,700 |
| 600 | 600 | $2,400 | $264,000 | $266,400 |
| midpoint | 525 | $2,400 | $231,000 | $233,400 |
| maximum | 800 | $2,600 | $352,000 | $354,600 |
Fee breakdown (as of 2026-05)
Permitting process
Viability (permitted uses)
- Long-term rental: with-restrictions Long-term rental (30+ days) of permitted interior ADU is allowed subject to owner-occupancy requirement (owner must occupy primary residence or the ADU). City requires rental registration.
- Short-term rental: no City of Fairfax EXPLICITLY PROHIBITS short-term rentals (Airbnb, VRBO, etc.) city-wide. This is a material distinction from surrounding Fairfax County and from most other VA jurisdictions.
- Office rental: no Office rental to third parties not permitted in residential zones in Fairfax City.
- Home office: with-restrictions Home occupation permitted under City of Fairfax Sec. 3.5.6 with restrictions on signage, customer traffic, and employees.
- Studio / workshop: yes Personal artist or workshop studio is a permitted accessory use within an existing residence.
- Agriculture: no City of Fairfax is fully urbanized; no agricultural zones. Limited urban agriculture (garden) permitted but no livestock or commercial agriculture.
- Relative support: yes Family-member occupancy is explicitly permitted; in fact, the owner-occupancy requirement is satisfied if a parent or adult-child of the owner occupies.
Contacts
Utilities
- Water: Fairfax Water (City of Fairfax is on Fairfax Water system) · 35d connect · $6,500
- Sewer: City of Fairfax Wastewater (treatment via Noman M. Cole Pollution Control Plant) · 35d connect · $7,500
- Electric: Dominion Energy Virginia · 30d connect · $2,200
- Gas: Washington Gas · 45d connect · $2,800
Property values & taxes
Construction timeline
Realistic total: best 6mo · typical 9mo · worst 14mo
Modular pathway inspectors are occasional with modular
Interior ADUs (the only currently permitted type in Fairfax City) typically use site-built construction rather than modular. Detached-modular pathway not yet established.
Financing
Insurance impact
HOA prevalence & preemption
City of Fairfax has mixed single-family and condo/townhouse stock; HOA prevalence is lower than surrounding county PD communities. Virginia POAA does not preempt HOA ADU bans.
Regulatory overlays (1)
- historic-district
Fairfax City's Old Town Historic District covers downtown core (Old Town Hall vicinity); ADUs in this district require Board of Architectural Review (BAR) approval and add 60-90 days plus design-compliance costs.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
- Amendment
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: City of Fairfax Zoning Ordinance Section 3.5.5.D (Accessory Dwelling Units), adopted 2020-06-23, last amended 2023-09-01
- 2025-10-14 — City of Fairfax Council work session: detached ADU expansion directed (city-ordinance)
At October 2025 work session City Council directed staff to draft an ordinance permitting detached ADUs in Fairfax City, with safeguards against neighborhood-impact concerns.
Effect: Initiates path to expand from interior-only to detached ADUs; final ordinance pending Spring 2026 hearings. - 2026-02-01 — Engage Fairfax public comment portal: ADU zoning standards (city-ordinance)
City opened community input portal for detached-ADU zoning options ahead of Planning Commission and Council Spring 2026 work sessions.
Effect: Public comment window for detached-ADU framework; no ordinance adopted yet.
Known issues (2)
- policy-review — Limits ADU options to basement/interior conversion; detached projects must wait for Spring 2026 ordinance.
- other — Eliminates STR income as ADU economic justification; long-term rental only.
County: no attribution (synthetic bucket)
No county
This city sits in the state's "no county" bucket — its ADU rules derive directly from state law and city ordinance without a county intermediary. No county-level sections apply.
Virginia state — ADU law and programs
State ADU law
Virginia has NOT enacted a statewide ADU preemption law. Virginia is a Dillon Rule state — localities possess only those powers expressly granted by the General Assembly — and the statutes granting zoning authority (Va. Code § 15.2-2280 et seq.) leave ADU regulation to local ordinances. ADU permission, setbacks, parking, size, and owner-occupancy rules therefore vary by county, independent city, and town. Virginia is unique in that it has 38 independent cities that function as counties (neither in nor subordinate to the surrounding county), meaning 'the county' for any given Virginia property may be an independent city rather than a true county. Several ADU preemption bills have been introduced in recent General Assembly sessions (2022 through 2025) without enactment; none have advanced past committee as of the Assembly's 2026 regular session adjournment.
State financing programs
Virginia does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. Virginia Housing (formerly the Virginia Housing Development Authority, VHDA — rebranded 2020) administers general first-time-homebuyer, down-payment-assistance (DPA), mortgage-credit-certificate, and rehabilitation products that can be applied to ADU-adjacent purchases or improvements when eligibility criteria are met, but none target ADU construction as a distinct product. The Virginia Department of Housing and Community Development (DHCD) administers federal HOME and CDBG pass-through funds that local jurisdictions can direct toward ADU-adjacent rehab, but there is no state-level ADU-dedicated line item. Federally available products (FHA 203(k), Fannie Mae HomeReady and HomeStyle Renovation, Freddie Mac CHOICERenovation) remain the primary ADU financing path for Virginia homeowners.
State housing programs
Virginia does not run a state-level pre-approved-ADU-plan catalog, statewide impact-fee-waiver statute for ADUs, or streamlined-review mandate. State-level programs that touch ADU-adjacent policy are coordinated primarily through the Department of Housing and Community Development (DHCD) and Virginia Housing, and act by funding or assisting local jurisdictions rather than by preemption. Local ADU activity — Arlington County's Accessory Dwellings program (detached ADUs permitted since 2008, liberalized 2020), Alexandria's accessory-dwelling ordinance, Fairfax County's accessory-living-unit program, and Charlottesville's 2021 zoning-code changes — is authorized under the localities' Va. Code § 15.2-2280 zoning authority, not by state mandate.
- DHCD Community Development Block Grant (CDBG) Program — Federal CDBG funds administered by DHCD to eligible non-entitlement Virginia localities for community-revitalization, housing-rehab, and infrastructure projects. Not ADU-specific. Participating localities can direct CDBG funds toward housing-rehab projects where local policy supports ADUs.
- DHCD HOME Investment Partnerships Program — Federal HOME funds administered by DHCD to Virginia participating jurisdictions and non-profits for affordable-housing acquisition, rehab, and new construction. Not ADU-specific; can be directed to ADU-adjacent rehab at local discretion.
- Virginia Housing Commission — Permanent advisory commission of the General Assembly that studies housing-policy questions and recommends legislation. Has periodically studied ADU preemption and missing-middle housing without recommending statewide enactment as of 2026-04-21.
- Local ADU ordinances under Va. Code § 15.2-2280 authority — Not a state program — listed here because Virginia ADU policy is executed entirely at the locality level under the § 15.2-2280 zoning grant. A homeowner seeking to build an ADU consults the zoning ordinance of the specific county, city, or town where the parcel is located.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Code
- 22038
Post Office
- 10660 Page Ave, 22030