Understanding Illinois Building Permits
Local Authority
Illinois permits are issued by your city, village, or county building department — requirements vary by location.
AHJ Review
Your Authority Having Jurisdiction (AHJ) reviews plans for code compliance, setbacks, and zoning rules.
Inspections
After approval, inspections verify your construction meets safety codes before final sign-off.
Structures That Typically Require Permits in Illinois
What's Involved in an Illinois Permit?
Depending on your project and location, you may need multiple reviews or permits before you can start construction. Here's what to expect in Illinois:
Typical Approvals Needed
- 1Zoning Review – Verifies setbacks, lot coverage, height limits, and land use compliance
- 2Building Review – Ensures structural, electrical, plumbing, and mechanical code compliance
- 3Stormwater Permit – May be required if you're in a floodzone or near waterways
Documents You May Need
- Plat of Survey – Often required, especially in Chicagoland suburbs
- Site Plan – Showing structure location, setbacks, and property lines
- Zoning Calculation Sheets – Required in some jurisdictions
- Building Plans/Drawings – Floor plans, elevations, and construction details
Well/Septic Systems
Properties with well or septic systems may need additional review from the County Health Department. Common in rural IL and unincorporated areas.
Concrete Foundations
Always wait until after you have your permit before pouring concrete. Building on an unpermitted foundation can cause major headaches.
Floodplain Areas
If you're in a FEMA floodzone, expect additional stormwater permits and possibly elevation certificates. Check your flood status before planning.
Good News for Illinois Builders
Unlike some neighboring states, Illinois typically doesn't have "double permit" situations where you need both county and municipal approvals. Most IL jurisdictions handle everything in one place — either your city/village or the county for unincorporated areas.
Don't Guess — Know Your Requirements
Enter your Illinois address and get exact setbacks, size limits, and permit requirements in minutes.
Popular Illinois Cities
Browse permit guides for these major Illinois municipalities, or check your specific address above.
How Permitech Works in Illinois
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Review Requirements
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Illinois Permit FAQ
Do I need a permit for a shed in Illinois?
Most Illinois municipalities require permits for sheds over 100-200 square feet. However, exemption thresholds vary by city — some exempt structures up to 120 sq ft, while others require permits for any structure. Check your specific address to be sure.
What are typical setback requirements in Illinois?
Setbacks vary widely by municipality and zoning district. Common requirements include 3-5 feet from side and rear property lines for accessory structures, but some areas require more. Chicago, for example, has specific setback rules that differ from suburbs.
How long does permit approval take in Illinois?
Simple shed permits in smaller towns may be approved in 1-5 days. Larger cities like Chicago can take 2-12 weeks depending on the project. Complete applications with all required documents are approved faster.
What if I build without a permit in Illinois?
Building without a required permit can result in fines, stop-work orders, required removal of the structure, and problems when selling your property. Many title companies and insurance providers check for permit compliance.
Ready to Build in Illinois?
Stop guessing about permit requirements. Get instant, accurate information for your specific Illinois address.