Winnebago County, IL Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Winnebago County, IL, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Max height
- 20 ft or house height, less
- Min setback
- 2.5 ft, rear/side lot lines
- Max rear-yard coverage
- 40% of required rear yard
- Footprint limit
- Can't exceed house footprint
Summary
Detached sheds and other accessory buildings in Winnebago County are capped at 20 feet tall, must sit 2.5 feet off rear and side lot lines, and can't cover more than 40% of the required rear yard.
No detached accessory structure shall exceed twenty (20) feet or the height of the principal building, whichever is less... All accessory structures must be located a minimum of two and one-half (2.5) feet from any rear or side lot line... The combined square footage of all detached accessory structures located in the rear yard shall not occupy more than forty percent (40%) of the required rear yard.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 64).
Full Breakdown
Under the county's Unified Development Ordinance, no detached accessory structure, sheds included, can exceed 20 feet in height or the height of the principal building, whichever is less, and it must be built at least 2.5 feet from any rear or side lot line. All detached accessory structures combined can't occupy more than 40% of the required rear yard, and a shed's footprint and gross floor area can't exceed the footprint of the house itself. A shed also can't go up before the principal building it's accessory to is built.
Violations & Fines
Structures built without meeting the height, setback, or coverage limits are subject to the county's Chapter 4 administrative code enforcement process, which can require removal or modification and impose fines until the structure is brought into compliance.
Frequently Asked Questions
How close to my property line can I build a shed in Winnebago County?
Is there a size limit on sheds in unincorporated Winnebago County?
Sources & Official References
Other rules in Winnebago County
How Winnebago County compares: Shed Permit Requirements by City·Compare Winnebago County to another location·View the Illinois accessory structures overview
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