ADUs are allowed in Franklin CityTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Franklin City, WI
Is your property eligible for an ADU?
# of Properties
12,292
Owner-occupied
89%
Zoning districts
18
Avg Home Value
$397,502
Median Lot Size
0.35 acres
Avg Income
$112,160
Residential Types:
12,292 housing units
RESIDENTIAL
100%
Zoning Districts:
13,366 parcels · 18 districts
R-SR
39%(5,240)
R-SE
24%(3,182)
R-MF
17%(2,237)
PDL
14%(1,808)
Other
7%(899)
ADU Rules
What can you build in Franklin City, WI?
Franklin City, WI 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: Conditional Use Permit
Interior / Attached ADU Size Limits
- –Maximum size for an internal accessory dwelling unit is 1,200 sq ft or 25% of the principal dwelling’s gross floor area, whichever is more.
Detached ADU Size Limits
- –Maximum size is the larger of 25% of the main home's gross floor area or 1,200 sq ft.
Max Units
- –1 ADU per lot (detached, attached, or internal)
Owner Occupancy
- –Owner must occupy either the principal dwelling or the ADU
Parking
- –0 min; max 1 space per dwelling for detached/attached ADU; internal ADU max not specified; exceptions: no minimum; up to 30% above max with permeable paving/green infrastructure and additional landscaping.
Rental Restrictions
- –Short-term rentals are allowed only if the ADU is the owner's primary residence; stays must be 3–30 days; hotel tax applies and a City Tourist Rooming House License is required. Long-term rentals: none specified.
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 Wisconsin municipalities
Rules change at the town line. Check the municipality your property is actually in.
Milwaukee County