ADU Pass
Dahlgren
ADU Pass helps homeowners in Dahlgren, King George 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
Dahlgren is an unincorporated CDP in King George County on the Potomac River that serves as the civilian community supporting the Naval Support Facility Dahlgren / Naval Surface Warfare Center Dahlgren Division (NSWCDD) — a major US Navy weapons-research installation occupying approximately 4,320 acres along the Potomac. The federal-fee NSWCDD parcels are federal exclusive jurisdiction (Title 10 / 50 U.S.C.) — civilian zoning does not reach them; on-installation housing is government-managed. Off-installation residential parcels in the Dahlgren CDP are governed by the King George County Zoning Subdivision Ordinance Article IV and Attachment B Use Performance Standards. King George has a codified ADU regime: attached/internal ADUs in qualifying districts proceed administratively, detached ADUs typically require a Special Use Permit, and STR of an ADU is prohibited (30-day-minimum-tenancy rule). Many residential parcels are governed by Active-Adult / family-housing HOAs serving the Navy commuter shed.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 200 | $2,400 | $58,800 | $61,200 |
| 600 | 600 | $2,400 | $176,400 | $178,800 |
| maximum | 1,000 | $2,400 | $294,000 | $296,400 |
Fee breakdown (as of 2026-04)
Permitting process
Viability (permitted uses)
- Long-term rental: yes Long-term rental of an ADU is generally permitted; Virginia landlord-tenant law (Va. Code Section 55.1-1200 et seq., the Virginia Residential Landlord and Tenant Act) governs.
- Short-term rental: no King George County prohibits short-term rental of an ADU under Article IV / Attachment B Use Performance Standards (an accessory dwelling shall not be offered, leased, or rented for tenancies of less than 30 days). STR is therefore not an available revenue model for an ADU in King George County.
- Office rental: with-restrictions Detached office rental requires a home-occupation permit or rezoning under home-occupation provisions.
- Home office: yes Home occupation is permitted in residential and rural districts with restrictions on signage, customer traffic, and outside storage.
- Studio / workshop: yes Personal studio (artist, music, woodworking) is a permitted accessory use in residential and agricultural districts.
- Agriculture: yes Agricultural / Rural districts expressly permit farm structures and the keeping of livestock subject to setback rules; Lee County and the Tidewater counties have substantial Agricultural and Rural Conservation district acreage.
- Relative support: yes Family / multi-generational accessory dwelling is the most common pattern and is expressly permitted.
Contacts
Staff: Planning Counter (Zoning Administrator / Permit Intake)
Utilities
- Water: Service Authority of King George County in service areas; private well elsewhere · 45d connect · $6,500
- Sewer: King George Service Authority in service areas; VDH-Three Rivers Health District for private septic elsewhere · 60d connect · $9,500
- Electric: Dominion Energy Virginia and Rappahannock Electric Cooperative · 30d connect · $2,400
- Gas: Limited natural-gas distribution outside the US 301 corridor; bottled propane is the norm · 14d connect · $1,900
Property values & taxes
Construction timeline
Realistic total: best 9mo · typical 13mo · worst 22mo
Modular pathway inspectors are occasional with modular
Financing
State ADU loans:
Insurance impact
HOA prevalence & preemption
Virginia has no HOA-ADU preemption. HOA covenants restricting ADUs are enforceable.
Regulatory overlays (3)
- wetland-overlay
Resource Protection Area 100-ft buffer from tidal waters, perennial streams, and wetlands restricts ADU siting near shorelines. Resource Management Area requires Water Quality Impact Assessment for non-trivial site disturbance. King George County is fully Tidewater under the CBPA framework. (map) - flood-zone
FEMA Special Flood Hazard Area mapping along major rivers and tributaries. Floodplain Development Permit required when any portion of the parcel is in the SFHA; finished floor must clear Base Flood Elevation plus Virginia freeboard. (map) - other
NSWCDD federal-fee parcels are federal exclusive jurisdiction outside county zoning. Off-base parcels in the Dahlgren CDP are governed by King George County zoning. Confirm parcel-specific federal-vs-county jurisdiction with the King George County Department of Community Development; some perimeter parcels may have explosive-quantity-distance arc constraints from the Navy testing range. (map)
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: King George County Zoning Subdivision Ordinance, Article IV and Attachment B (Use Performance Standards) (governs Dahlgren), adopted 2010-01-01, last amended 2024-01-01
- 1979-01-01 — Va. Code Section 15.2-2280 zoning authority codified (Dillon Rule baseline) (state-statute)
Virginia delegated zoning authority to counties, cities, and towns without an ADU-specific preemption.
Effect: Each Virginia locality regulates ADUs through its own zoning ordinance; ADUs are not automatically permitted statewide.
Known issues (1)
- other — STR pro forma is not viable for ADU construction in King George County; only long-term rental and owner-use scenarios are economically applicable.
King George County — county ADU rules and overlays
County ADU ordinance
King George County's Zoning Ordinance (Appendix A of the Code of Ordinances) addresses Accessory Dwelling Units explicitly through Article IV permitted-use schedules and the Use Performance Standards in Attachment B. ADUs are permitted in certain residential and rural districts, with attached or internal ADUs generally available by right or with administrative approval, and detached ADUs typically requiring a Special Use Permit (SUP) in some residential districts. The ordinance imposes performance standards including a prohibition on tenancies of less than 30 days (i.e., short-term-rental use of an ADU is not permitted), size caps tied to a percentage of the principal dwelling's footprint or a fixed maximum square footage, and parking, setback, and connection-to-utility requirements. King George is one of the more codified ADU regimes in rural / exurban Virginia — applicants get a clearer regulatory path here than in counties that handle ADUs purely through Conditional Use Permits without standalone provisions. Confirm current ordinance text and the per-district treatment (R-1, R-2, A-1, etc.) with the Department of Community Development at 540-775-7111.
County regulatory overlays
King George County administers a Floodplain Management Overlay District tied to FEMA Special Flood Hazard Areas along the Potomac and Rappahannock Rivers and their tributaries, plus the Chesapeake Bay Preservation Area Overlay covering the entire county under the Chesapeake Bay Preservation Act. The county also recognizes a substantial Naval Support Facility Dahlgren federal-land footprint (~4,320 acres) on the Potomac, which is outside county zoning jurisdiction but is reflected in airport / range-noise planning and in regional Coastal Resilience Master Plan coordination. Locally adopted Agricultural and Forestal Districts (state-enabled under Va. Code § 15.2-4300 et seq.) preserve farmland against incompatible adjacent development. King George has NO designated coastal-commission analog (none exists in Virginia), NO statewide WUI regulatory overlay, and NO seismic-retrofit overlay. The Dahlgren installation generates an FAA / Navy-coordinated airspace and weapons-test-range buffer; ADU siting near the installation should consult the regional planning materials.
County permitting (unincorporated parcels)
King George County's Department of Community Development is a one-stop department combining planning, zoning, building, and code-enforcement functions. A typical ADU-like permit bundle includes: (1) pre-application zoning inquiry to determine whether the project qualifies for administrative approval (attached / internal ADU in a qualifying district) or requires a Special Use Permit (detached ADU in many residential districts), (2) zoning permit confirming use compliance and Article IV / Attachment B performance standards, (3) Chesapeake Bay Preservation Act review — King George IS a Tidewater locality fully subject to the CBPA — including Resource Protection Area (RPA) and Resource Management Area (RMA) buffer review, (4) building permit with stamped residential plans, (5) electrical, plumbing, and mechanical trade permits, (6) Virginia Department of Health (VDH) Three Rivers Health District construction permit for well and onsite septic for any parcel not served by King George County Service Authority public water and sewer (the KGCSA serves the Dahlgren and Route 3 corridors but not the entire county), (7) floodplain development permit if any portion of the parcel is within the FEMA Special Flood Hazard Area along the Potomac, Rappahannock, or their tributaries, and (8) erosion-and-sediment-control / land-disturbance permit. The Naval Support Facility Dahlgren is federal land and is NOT subject to county permitting; ADU projects on the federal installation are not in scope.
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
- 22448
Post Office
- 17285 Dahlgren Rd, 22448