ADUs are allowed in Unincorporated MontgomeryTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated Montgomery, VA
Is your property eligible for an ADU?
# of Properties
16,538
Owner-occupied
61%
Zoning districts
25
Avg Home Value
$217,420
Median Lot Size
1.29 acres
Avg Income
$89,613
Residential Types:
16,538 housing units
Single Family
99%
Apts (4+ units)
1%
Zoning Districts:
20,860 parcels · 25 districts
A1
78%(16,171)
R2
7%(1,453)
PUDRES
5%(1,057)
R1
3%(586)
Other
8%(1,593)
ADU Rules
What can you build in Unincorporated Montgomery, VA?
Unincorporated Montgomery, VA follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum internal/attached ADU size: 2,000 sq ft in A-1 and C-1; 1,200 sq ft in R, R-1, R-2, and R-3.
Detached ADU Size Limits
- –Maximum size: 2,000 sq ft in A-1 and C-1; 1,200 sq ft in R‑Rural Residential, R‑1, R‑2, and R‑3.
- –Accessory structure size cannot exceed the principal building’s square footage unless a Special Use Permit is approved.
Max Units
- –A-1 Detached: 1 ADU on parcels ≥5 acres; +1 ADU per each additional 20 acres (no absolute cap).
- –A-1 Attached/Internal: Not more than 1 ADU within any single-family principal dwelling.
- –R-Rural/R-1/R-2/R-3: Detached 1 ADU per parcel; Attached 1 ADU per parcel; total dwellings per parcel ≤ 2.
Owner Occupancy
- –No owner-occupancy required.
Parking
- –1 space/ADU; max not stated. Exceptions: in R-Rural, R-1, R-2, R-3 districts at least one additional off-street space is required and it may not be in the front yard except on an existing driveway; countywide, the minimum may be reduced by up to 20% with an approved mass/alternative transportation plan.
ADU State Law
What can you build in Virginia?
- –Virginia does not have a statewide ADU mandate; ADU rules are set by individual municipalities.
- –Building/fire codes are set statewide, but whether an ADU is allowed is local zoning.
- –SB 304 would have mandated ADUs. It passed the Virginia Senate in 2024 but was continued/left in House committee (i.e., not enacted statewide)
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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Learn the key rules and size limits for ADUs
Is your property eligible for an ADU?
ADU rules in other Virginia municipalities
Rules change at the town line. Check the municipality your property is actually in.
Montgomery County