Quick Answer — Illinois
In most Illinois jurisdictions, sheds under 150 sq ft with no electrical, plumbing, or mechanical systems do not require a building permit. Setback requirements and zoning rules still apply to all sheds, and utility connections require trade permits. Verify with your specific city or county before building.
Statewide Permit Threshold
Illinois building permits are governed at the local level. Most Chicago suburbs and downstate cities use thresholds of 120–200 sq ft. The City of Chicago has strict permit requirements for all structures. Always verify with your specific municipality.
| Shed Type | Permit Required? | Notes |
|---|---|---|
| Under 150 sq ft, no utilities, detached | NO | Typical statewide baseline. Your city or county may have a lower threshold. |
| 150 sq ft or over | YES | Building permit required. Contact your local building department to apply. |
| Any shed with electricity | YES | Electrical permit required in all Illinois jurisdictions. |
| Attached to house | YES | Treated as a home addition — full building permit required. |
| In FEMA flood hazard area | YES | Additional flood zone requirements apply regardless of shed size. |
⚠️ Your City or County May Have Different Rules
The threshold above is the typical statewide default. Many cities and counties set their own lower thresholds. Always call your local building department with your address to confirm the current rules for your specific location.Setback Requirements
Even permit-exempt sheds in Illinois must comply with local setback requirements — minimum distances from property lines, easements, and other structures. Typical setbacks in Illinois residential zones:
- Rear property line: 5 feet minimum (verify locally — may be different in your zone)
- Side property lines: 5 feet minimum (verify locally)
- Front yard: Sheds are not permitted in the front yard in most Illinois residential zones
- Easements: Sheds cannot be placed over utility, drainage, or access easements
How to Apply for a Shed Permit in Illinois
- Determine your jurisdiction — Confirm whether your property is inside an incorporated city or in an unincorporated county area. Permit authority differs between the two.
- Contact your building department — Call or visit your city's or county's building department to confirm current requirements and get the application form or portal link.
- Prepare your documents — Site plan showing your lot, house, proposed shed location, and setback distances; shed dimensions; foundation type; utility information.
- Submit your application — Online, by mail, or in person depending on your jurisdiction.
- Pay the permit fee — Typical range in Illinois: $75–$300 for a residential shed.
- Schedule inspections — Follow your permit's required inspection schedule.
Key Building Department Contacts
📞 Contact Information
Chicago: (312) 744-5000Cook County: (312) 603-0500
Disclaimer: This page is for informational purposes only. Permit rules change. Always verify current requirements with your local building department before beginning any construction. Information accurate as of May 2025.
Frequently Asked Questions — Illinois Shed Permits
The typical baseline threshold in Illinois is 150 square feet for a one-story detached accessory structure with no utilities. However, your specific city or county may have a different (often lower) threshold. Always verify with your local building department before assuming you're exempt.
Yes — setback requirements come from your local zoning code and apply to all sheds regardless of whether a building permit is required. In Illinois, the typical residential setback is 5 feet from rear and side property lines, but your specific zoning district may require more. Always measure and verify before placing your shed.
No — an electrical permit is required for any electrical work in Illinois, just as in every other U.S. state. Running power to a shed, even for a single outlet, requires an electrical permit and inspection. In most Illinois jurisdictions, electrical work on a shed also triggers a building permit for the shed structure itself.
Most Illinois building departments require: a site plan showing property lines and the proposed shed location with setback distances, shed dimensions (width, depth, height), foundation type, and a description of any utility connections. Larger sheds or those in flood zones may require additional engineering documentation. See our free permit application checklist for a full list.
Simple residential shed permits in Illinois typically take 1–3 weeks from application to issued permit in most jurisdictions. Large metro areas may take longer during busy construction seasons. Ask your building department about current processing times when you apply.