ADUs are allowed in BillingsTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Billings, MT
Is your property eligible for an ADU?
# of Properties
7,111
Owner-occupied
51%
Zoning districts
25
Avg Home Value
$418,718
Median Lot Size
0.03 acres
Avg Income
$77,641
Residential Types:
7,111 housing units
Single Family
35%
Apts (4+ units)
4%
Condos
58%
Other
2%
Zoning Districts:
49,925 parcels · 25 districts
N3
30%(14,797)
N2
24%(12,098)
PUD
11%(5,706)
N1
10%(4,752)
Other
25%(12,572)
ADU Rules
What can you build in Billings, MT?
Billings, MT 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 size no larger than the primary dwelling's gross floor area
Detached ADU Size Limits
- –Maximum detached ADU floor area is the lesser of 80% of the principal dwelling’s gross floor area or 750 sq ft.
Max Units
- –1 ADU per single-family lot
Owner Occupancy
- –Owner must live in either dwelling at least six months per year.
Parking
- –1 space/ADU; max 2 spaces; CBD/EBURD has no minimum; planning staff can grant exceptions; on-street spaces adjacent may count toward required parking.
Rental Restrictions
- –Owner-occupied unit may not be rented (no third-party rentals).
- –If both a principal dwelling and an ADU exist, only one unit may be used as a short-term rental and an STR permit and business license are required.
- –An ADU permanently deed-restricted as affordable housing may not receive a short-term rental permit.
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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ADU rules in other Montana municipalities
Rules change at the town line. Check the municipality your property is actually in.
Yellowstone County