Statewide reference · Updated July 2026
Virginia ADU Rules by County
A plain-English snapshot of where accessory dwelling units stand in Virginia's major localities today — and how SB 531 changes each one on July 1, 2027. Search your county below.
Read this first: Many Virginia counties are actively rewriting their zoning ordinances to comply with SB 531, so specifics change often. This table is a starting point, not legal advice. Always verify current rules for your exact parcel — our Quick-Fit Check and Readiness Assessment do exactly that.
| County / City | ADUs allowed today? | Detached allowed? | Approx. max size | Owner-occupancy today | Notes / 2027 change |
|---|---|---|---|---|---|
| Loudoun | Yes — by-right | Yes | Lesser of ~70% of main home or district cap (~2,500 sf rural / 1,200 sf urban) | Not required (none stated) | Largely SB 531-aligned already; 2027 confirms $500 fee & setback parity. |
| Fairfax | Interior: yes (permit); Detached: special permit | Yes — but special permit + 2 ac today | Interior ~800 sf / 40%; Detached ~1,200 sf | Yes, required | 2027: detached becomes by-right, owner-occupancy dropped, fee capped. |
| Arlington | Yes — admin permit | Yes (since 2019) | ~750 sf / 35% of combined floor area | Yes, required | Owner-occupancy conflicts with SB 531 and will need revisiting. |
| Prince William | No (general residential) | No today | N/A residential | N/A | Big change: 2027 forces by-right ADUs; current prohibition overridden. |
| Fauquier | Yes — most rural/residential districts | Yes | ~800 sf (1,000 sf on 5+ ac; up to 1,400 sf conversions) | Verify locally | Must become by-right; family/fee/setback to conform. Verify current ordinance. |
| Clarke | Limited — AOC/FOC districts, 6+ ac | Yes (<600 sf) | Under 600 sf heated | Verify locally | 6-ac minimum & district limits likely overridden by SB 531; update underway. |
| Albemarle | Yes — by-right (interior only) | No — detached prohibited today | 35% of structure GFA | Yes, required | 2027: must allow detached & drop owner-occupancy. Check AC44 updates. |
| Henrico | Yes — by-right or conditional by district | Yes (≥10 ft separation) | Verify (§24-4406) | Verify locally | Actively revising (2026); permit-required districts move to by-right. |
| Chesterfield | Full ADU by conditional use permit | Per ZOMod standards | ~800 sf or 30% of main GFA | Family-only (verify) | ZOMod adopted 2025; SB 531 drops the CUP gate & family limit. |
| Stafford | Yes — administrative | Guest-house form (verify by district) | ≤25% of principal dwelling GFA | In effect (no rentals today) | 2027: by-right on SF lots, family limit removed, fee capped. |
| City of Alexandria | Yes — admin permit (since 2021) | Yes (new detached) | ~1/3 of main-house floor area (or set floor) | Required at permit | Already administrative; SB 531 sets by-right/$500/no-family floor. |
Don't see your county, or need the exact current rule?
We serve all of Virginia and track ordinance changes as counties update for 2027. The fastest way to get a definitive answer for your specific parcel is the free Quick-Fit Check, followed by a site-specific Readiness Assessment.
Get your county's rules confirmed for your lot.
Free, two minutes, no obligation.