ADU Pass
Philomont
ADU Pass helps homeowners in Philomont, 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
ADUs allowed under Loudoun County's 2023 ZOR accessory-apartment framework with size cap and owner-occupancy. Philomont's location in the Rural Policy Area means most parcels are in AR-1 with 25-acre minimums and conservation-oriented density. ADU placement on smaller historic village-core parcels (~1-5 acres) is more practical than on outlying AR-1 acreage.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 220 | $925 | $99,000 | $99,925 |
| 600 | 600 | $1,490 | $270,000 | $271,490 |
| midpoint | 600 | $1,490 | $270,000 | $271,490 |
| 1000 | 1,000 | $5,650 | $450,000 | $455,650 |
Fee breakdown (as of 2026-05)
Permitting process
Viability (permitted uses)
- Long-term rental: with-restrictions Long-term rental permitted subject to owner-occupancy. Limited year-round tenant pool due to rural distance to employment (~25 miles to Leesburg, ~50 miles to DC).
- Short-term rental: with-restrictions Loudoun County 2023 ZOR regulates STRs with zoning permit; Philomont's wine-country / horse-country location creates strong STR demand for DC weekend visitors, wedding venues, and Virginia Wine Country Trail traffic.
- Office rental: no Commercial office rental not permitted in AR/TR districts without rezoning.
- Home office: yes Home occupation permitted under standard county conditions.
- Studio / workshop: yes Personal artist/workshop studio is a normal accessory use; Philomont has art and antique-craft community presence.
- Agriculture: yes AR-1 / AR-2 districts explicitly support agricultural accessory uses including vineyards, equestrian, livestock; ADU on a working farm or vineyard is canonical.
- Relative support: yes Multigenerational accessory apartment for family members supported under owner-occupancy framework; common pattern for inherited Loudoun family farms.
Incentives
Contacts
Utilities
- Water: Private well (Philomont is outside Loudoun Water service area; western Loudoun rural) · 75d connect · $11,000
- Sewer: Private septic system (Virginia Department of Health, Loudoun County Health Department regulated) · 90d connect · $17,000
- Electric: NOVEC (Northern Virginia Electric Cooperative) for most of western Loudoun; Dominion Energy on some corridor parcels · 45d connect · $2,500
- Gas: No piped natural gas in western Loudoun; propane only via local suppliers · 21d connect · $2,300
Property values & taxes
Construction timeline
Realistic total: best 10mo · typical 13mo · worst 20mo
Modular pathway inspectors are occasional with modular
Philomont access via Snickersville Turnpike (Route 734) and Route 50 is rural two-lane; oversize modular delivery requires route survey.
Financing
Insurance impact
HOA prevalence & preemption
Philomont has very low HOA prevalence — mostly family-held rural acreage and a few large equestrian estates. New cluster-development subdivisions are rare in the Rural Policy Area.
Regulatory overlays (1)
- other
Loudoun County Rural Policy Area framework (2025 Comprehensive Plan) intentionally limits density in western Loudoun. ADUs permitted but broader policy framework constrains supporting infrastructure (no public water/sewer extension to Philomont).
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
- Amendment
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: Loudoun County 2023 Zoning Ordinance Rewrite (ZOR) — Accessory Apartment provisions, adopted 2023-01-01, last amended 2023-01-01
- 1757-01-01 — Loudoun County established by the Virginia General Assembly (local-ordinance)
Loudoun County formed in 1757 from Fairfax County. Named for John Campbell, 4th Earl of Loudoun. Philomont village settled around the early-19th-century Loudoun Mill at Snickersville Turnpike crossing.
Effect: Establishes Loudoun County as the unit of land-use authority over Philomont. - 2023-01-01 — Loudoun County 2023 Zoning Ordinance Rewrite (ZOR) — Chapter 4 Use-Specific Standards and Chapter 9 Attainable Housing (county-ordinance)
Loudoun County comprehensively rewrote its zoning ordinance with explicit accessory-apartment standards permitted by-right in most residential districts. Applies to all UNINCORPORATED Loudoun including Philomont.
Effect: Provides current operative ADU framework for Philomont; pre-dates SB531 January 1, 2026 exemption deadline. - 2026-04-14 — Virginia SB531 — statewide by-right ADU mandate signed by Governor Spanberger (state-law)
SB531 signed by Governor Spanberger, effective July 1, 2027. By-right ADUs in single-family zones, $500 permit fee cap. Localities with ADU ordinances by January 1, 2026 are exempt.
Effect: Loudoun County's 2023 ZOR satisfies the exemption; Philomont remains under county rules.
Known issues (2)
- policy-review — Older parcels with aged septic systems face high VDH-driven cost to add an ADU; private well/septic adds $25K-$35K to project cost vs. public utility.
- policy-review — SE process adds 5-8 months and ~$3500 in application fees plus public hearing risk.
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
- 20131
Post Office
- 36550 Jeb Stuart Rd, 20131