ADUs are allowed in Unincorporated BoiseTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated Boise, ID
Is your property eligible for an ADU?
# of Properties
4,478
Owner-occupied
75%
Zoning districts
8
Avg Home Value
$271,569
Median Lot Size
4.40 acres
Avg Income
$86,210
Residential Types:
4,478 housing units
Single Family
11%
2-3 Family
22%
Apts (4+ units)
9%
Other
57%
Zoning Districts:
66 parcels · 8 districts
APD
42%(28)
AG
30%(20)
R
12%(8)
P
6%(4)
Other
9%(6)
ADU Rules
What can you build in Unincorporated Boise, ID?
Unincorporated Boise, ID 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
- –Size cap by lot size: 0 sq ft (not allowed) on lots up to 2 acres; maximum 1,000 sq ft on lots over 2 and up to 4 acres; no size cap on lots 4.01 acres or larger.
Detached ADU Size Limits
- –Maximum ADU size by lot area: 0 sq ft on lots 2 acres or smaller; up to 1,000 sq ft on lots over 2 and up to 4 acres; no size cap on 4.01 acres and above.
Max Units
- –0 ADUs per lot for parcels 2.00 acres or smaller.
- –1 ADU per lot for parcels 2.01–4.00 acres with a single-family dwelling; max 1,000 sq ft and max 2 bedrooms.
- –1 ADU per lot for parcels 4.01 acres and larger with a single-family dwelling; no size limit stated.
Parking
- –No numeric min/max for ADUs; minimum not set; if residential use is conditional, parking varies per Table 4.1.D.9; general standards apply when 5+ spaces are provided.
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 Idaho municipalities
Rules change at the town line. Check the municipality your property is actually in.
Boise County