ADUs are allowed in MarionTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Marion, IA
Is your property eligible for an ADU?
# of Properties
16,455
Owner-occupied
87%
Zoning districts
36
Avg Home Value
$331,929
Median Lot Size
0.24 acres
Avg Income
$92,880
Residential Types:
16,455 housing units
Residential
100%
Zoning Districts:
16,719 parcels · 36 districts
SR-2
37%(6,247)
SR-3
22%(3,670)
SR-5
9%(1,426)
PUD
5%(911)
Other
27%(4,465)
ADU Rules
What can you build in Marion, IA?
Marion, IA 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 ADU size is the larger of 1,000 sq ft or 50% of the principal dwelling’s size.
Detached ADU Size Limits
- –Maximum size is 1,000 sq ft or 50% of the principal dwelling’s floor area, whichever is larger.
Max Units
- –1 ADU per lot for single-unit principal dwellings.
- –No max specified for multi-unit principal structures (duplex, triplex, fourplex, multifamily).
Owner Occupancy
- –Owner-occupancy not required; non-owner-occupied ADUs allowed with annual registration and inspection.
Parking
- –No minimum or maximum parking required for ADUs; all parking must be on the same lot as the principal dwelling; generally only one driveway access; any new ADU garage door must be set back 25 ft from the facing property line; in Uptown U-1 and U-2 districts, accessory off-street parking is not required citywide.
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 Iowa municipalities
Rules change at the town line. Check the municipality your property is actually in.
Linn County