Understanding Illinois Building Permits
Local Authority
Illinois permits are issued by your city, village, or county building department, and 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.
Your permit check is free. The fine for skipping it isn't.
Building without a permit in Illinois can mean fines, stop-work orders, or problems when you sell. Get your requirements verified in minutes, not days of phone calls.
How Permitech Works in Illinois
First, find out if you even need a permit
Enter your Illinois address. We tell you whether your specific project needs a permit at all, based on the real rules for your jurisdiction, not a generic “it depends.” No more guessing, no more calling the building department, no more getting passed around on hold.
New kind of productYour Permit Workspace loads. And yes, this is a thing now
Here's how permits normally work: you hunt through your city's website, call the building department, translate code-speak into plain English, download a PDF that looks like it was made in 1997, and guess at the half-dozen things you might be missing. Then you drive downtown and hope you got it right.
The Permit Workspace replaces all of that.
It's a dashboard built for your exact permit, in any jurisdiction we cover, with every Illinois rule, fee, deadline, document, and code citation already researched, organized, and waiting for you. Most homeowners and contractors don't know a product like this exists because nothing like it existed until recently. That's the whole point.
24/7 guided support, from AI and from us
You're never stuck. Your Workspace comes with round-the-clock support from the world's leading AI models, grounded in your live Illinois jurisdiction rules, not a generic chatbot. And when you need a real human, our permit team is reachable day, night, and weekends.
We're open when the building department sleeps. Evenings, Saturdays, Sundays. While your local permit desk is closed, we're still answering questions and moving your project forward.
Work the permit inside the Workspace, then export a single PDF
Upload your files, mark off tasks as you complete them, leave notes, and keep everything for your Illinois permit in one place: Plat of Survey, photos, HOA letter, site plan, whatever your project needs. When you're ready, export a single PDF that has everything you've gathered, plus a Permit Application Reference Sheet with your project data pre-organized into the fields your building department will ask for, so you can copy it straight onto their form.
Need a site plan? Add one for $99
Most building departments (especially in Illinois) require a drawn-to-scale site plan showing your structure, setbacks, and property lines. Upload your Plat of Survey (or we'll pull GIS data if your jurisdiction accepts it) and our site plan tool generates a site plan for your building department. Note: this is not a Plat of Survey. If you have one on file, send it over and we'll mark your project to scale. If not, you may need a licensed surveyor first.
Or let us do it for you. Done-For-You from $199
Prefer to hand it off? Upgrade inside your Workspace and our permit techs prepare and submit the full application for your Illinois project. You approve, we handle the rest.
DIY Permit Package: $39 $60
Spring Ahead pricing through June 21, 2026. Done-For-You from $199/project.
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?
Traditional permit services charge $500–$1,500. Skipping the permit risks $500–$10,000+ in fines.
Permitech gives you verified, address-specific requirements in minutes, built by a former permit tech who processed 500+ Illinois permits per year. DIY for $39, or Done-For-You from $199.