County Rules
Virginia ADU rules, county by county.
A working snapshot of ADU rules across 18 Virginia counties and cities. Rules change constantly and localities differ. Always verify with the local zoning department before you design.
This table reflects rules as of publication. On July 1, 2027, SB 531 supersedes local restrictions where they conflict with the by-right ADU provisions. When in doubt, we'll confirm your county in a Readiness Assessment.
| County / City | Detached ADU today | Size cap | Occupancy | Notes |
|---|---|---|---|---|
| Loudoun County | Allowed by-right today | Lesser of ~70% of main home or district cap | No family / owner-occ. requirement | Best-positioned county. Verify sewer/septic on rural AR-1 lots. |
| Fairfax County | Interior today; detached needs SUP + 2 acres | Interior ~800 sf / 40%; detached ~1,200 sf | Owner-occupancy required today | SB 531 makes detached by-right in 2027 and drops owner-occupancy. |
| Arlington County | Allowed by administrative permit (since 2019) | ~750 sf / 35% of combined floor area | Owner-occupancy required today | Lot coverage, tree preservation and parking often the constraints. |
| Prince William County | General ADUs NOT allowed today | N/A on standard SF lots | N/A today | SB 531 forces by-right ADUs county-wide in 2027 — biggest change on this list. |
| Fauquier County | One accessory dwelling per home in most districts | ~800 sf (up to 1,000 sf on 5+ acres) | Varies by district | Health-department septic approval is the pacing item. |
| Albemarle County | Interior only today; detached prohibited | Interior capped at 35% of GFA | Owner-occupancy required today | SB 531 requires detached by-right and drops owner-occ. in 2027. |
| City of Alexandria | Allowed by-right since 2021 | Capped relative to the principal dwelling — confirm current §7-203 | Recently amended — confirm with Planning & Zoning | Administrative ADU permit; BAR review applies in historic districts. |
| City of Richmond | By-right in all residential districts (2023) | 1/3 of the main home's floor area, or 500 sf — whichever is greater | No owner-occupancy or family-relation requirement | One of the most permissive ADU frameworks in Virginia today. |
| Henrico County | By-right, accessory to a single-family detached home | Lesser of 800 sf or 35% of the main home's finished floor area | No family-relation requirement found; confirm owner-occupancy | One ADU per lot; 30-day minimum lease — no short-term rentals. |
| Chesterfield County | Conditional Use Permit required today | No ADU-specific cap; accessory buildings ≤ the main home's GFA | Set case-by-case as CUP conditions | Zoning rewrite (ZOMod) underway — status may change before 2027. |
| Stafford County | Administrative permit — family/guest use only, no rentals | 25% of the principal dwelling's gross floor area | Family-relation framework; rental use prohibited today | Rental ban and family-relation rules conflict with SB 531 — expect amendment. |
| City of Virginia Beach | Detached units limited to the R-40 district today | Accessory structures generally 500 sf or 20% of the main home (30% in R-30/R-40) | Confirm with Planning — not settled in current code review | APZ-1 / Clear Zone rules near NAS Oceana restrict many parcels. |
| City of Norfolk | By-right in certain single-family districts (2025 update) | Confirm current cap — rules were amended in September 2025 | Loosened in the 2025 amendment; confirm current terms | Flood and resilience overlays are often the real constraint. |
| City of Chesapeake | No full ADU today — guesthouse only, no kitchen | No ADU cap; accessory lot coverage ≤ 75% of the principal building's | Guests, relatives or domestic employees only — no rentals | Requires a single-family lot of at least 20,000 sf. |
| City of Newport News | Legalized city-wide in September 2024 | Standards set by ZT-2024-0003 — confirm with Planning | Confirm current terms with Planning | Recent reversal of a long-standing second-unit prohibition. |
| City of Hampton | Legalized city-wide in November 2025 | Standards set by the November 2025 ordinance — confirm with Planning | Confirm current terms with Planning | Newest ADU framework in Hampton Roads; Langley AFB AICUZ applies. |
| City of Charlottesville | By-right under the 2024 Development Code | Confirm current caps in Chapter 34 — the code was rewritten in 2024 | Confirm current terms — the 2024 rewrite changed prior rules | Don't confuse accessory dwellings with the city's Affordable Dwelling Unit program. |
| City of Roanoke | By-right after 2024 zoning amendments | Detached: lesser of 800 sf or 80% of the main home. Attached: 40% of the building. | Confirm §36.2-409.1 — 2024 amendments revised prior rules | Pre-approved ADU plans available from a city design competition. |