Accessory Structures in Lake County, IN (2026)
4 rules for unincorporated Lake County, Indiana.
Verified from official government sources
ADU Rules
Unincorporated Lake County allows two ADU forms: a detached backyard cottage (special exception in A-1 and R) and an interior secondary suite (permitted in A-1 and R). Both cap floor area at 49% of the home or 580 sq ft and require owner occupancy.
Accessory Dwelling Units in Unincorporated Lake County
Some RestrictionsLake County UDO No. 2560, 154-9-030.G, H
The floor area of a backyard cottage may not exceed 49% of the floor area of the principal dwelling unit or 580 square feet, whichever is less. The height of the building occupied by a backyard cottage may not exceed 24 feet or the height of the detached house, whichever is less.
Shed & Carport Rules
On agricultural and residential lots in unincorporated Lake County, detached sheds, garages, and pole buildings must sit in the rear yard, set back at least 5 ft from side and rear lot lines. Size and height scale with lot area; lots up to one acre allow two such buildings.
Shed and Detached Storage Building Rules
Some RestrictionsLake County UDO No. 2560, 154-9-020.C
Detached accessory garages, detached accessory storage buildings, and similar accessory structures must be set back at least 5 feet from side and rear lot lines, provided that when located on corner lots such buildings may not be placed closer the street than the principal building.
Garage Conversions
Unincorporated Lake County has no rule banning garage conversions outright, but converting interior floor area into a secondary suite (an ADU inside a detached house) triggers the UDO's secondary-suite standards: one per lot, capped at 49% of the home or 580 sq ft, owner occupancy, and a recorded deed restriction.
Converting a Garage to Living Space
Some RestrictionsLake County UDO No. 2560, 154-9-040.F
Secondary suites may be created by: 1. Converting existing floor area within the interior of a detached house (e.g., attic or basement) to a secondary suite; 2. Adding floor area to an existing detached house to accommodate a secondary suite.
Tiny Homes
Unincorporated Lake County has no separate 'tiny home' ordinance. A tiny house used as a second dwelling fits the UDO's backyard cottage category: a small detached accessory dwelling, special exception in A-1 and R districts, capped at 580 sq ft, one per lot, with owner occupancy.
Tiny Homes and Backyard Cottages
Some RestrictionsLake County UDO No. 2560, 154-9-030.A
A backyard cottage is a small accessory building occupied by a single, self-contained accessory dwelling unit. Backyard cottages are located on the same lot as but not attached to a detached house.
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