ADUs are allowed in Unincorporated McHenryTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated McHenry, IL
Is your property eligible for an ADU?
# of Properties
10,041
Owner-occupied
37%
Zoning districts
193
Avg Home Value
$39,097
Median Lot Size
0.41 acres
Avg Income
$110,462
Residential Types:
10,041 housing units
Single Family
30%
Apts (4+ units)
65%
Other
5%
Zoning Districts:
40,978 parcels · 193 districts
R1
44%(18,009)
A1
29%(11,760)
E1
10%(4,251)
E3
2%(950)
Other
15%(6,008)
ADU Rules
What can you build in Unincorporated McHenry, IL?
Unincorporated McHenry, IL 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 of an internal ancillary dwelling unit may not exceed the size of the principal residence (using available floor area measure).
Detached ADU Size Limits
- –Maximum footprint of a detached accessory dwelling unit is 900 sq ft.
- –Detached ADU cannot be larger than the principal residence.
Max Units
- –1 ADU per lot or parcel
Owner Occupancy
- –Owner-occupied; owner may reside in the principal or ADU
Parking
- –1 space/ADU; max not specified; on-street parking substitution allowed only in the Legacy Neighborhood Overlay District on streets ≤35 mph and not prohibited by the road authority; parking must be on the same lot or on a contiguous commonly owned lot with a deed restriction in agricultural/residential districts
Rental Restrictions
- –Owner-occupancy required; no one may occupy the owner's unit when the owner is not residing on the property.
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 Illinois municipalities
Rules change at the town line. Check the municipality your property is actually in.
McHenry County
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