Building Permits in Madison County, Illinois
Adopted Construction Codes
These are the state-level code editions for Illinois. They apply in Madison Countyunless a verified local adoption or amendment is noted — in local-adoption states, confirm the city or county's own code editions with the building department.
Permit Requirements
Statewide baseline under the codes as adopted by Illinois. Local amendments and fee schedules for Madison County are being verified — use the building department contacts to confirm before you build.
Exemptions: Illinois has no statewide building-permit system: the Capital Development Board confirms the state issues no permits and performs no inspections for privately funded projects, and municipalities/counties are not required to adopt building codes — permitting is entirely a local (often home-rule) function. Since January 1, 2025, Public Act 103-0510 (20 ILCS 3105/10.09-5) requires that residential construction meet minimum standards at least as stringent as the International Residential Code, but this sets construction standards, not permit rules. Whether a permit is required, and what is exempt, is set by each municipality or county.
Exemptions: No statewide rule — deck permits are a municipal/county matter in Illinois. The IRC R105.2 default many jurisdictions adopt exempts decks not exceeding 200 sq ft that are not more than 30 inches above grade and not attached to a dwelling; attached or elevated decks require a permit under that model rule. Local amendments vary, so confirm with the local building department.
Exemptions: No statewide permit rule — electrical permit requirements are set by each Illinois municipality or county, and the state issues no permits for private projects (Illinois Capital Development Board). Under the IRC R105.2 defaults many jurisdictions adopt, only minor work such as listed portable equipment and minor repairs is exempt; new wiring, circuits, and service changes require a permit. Local amendments vary, so verify with the local authority having jurisdiction.
Exemptions: No statewide rule — fence permit requirements are set by each Illinois municipality or county (Illinois Capital Development Board confirms the state issues no building permits). The IRC R105.2 default many jurisdictions start from exempts fences not over 7 feet high, but local codes and zoning ordinances frequently impose lower limits (often 6 feet) or require permits at any height. Check the local building/zoning office.
Exemptions: No statewide permit rule — reroofing permits are set by each Illinois municipality or county, and the state issues no permits (Illinois Capital Development Board). Reroofing is not on the IRC R105.2 exempt-work list, so jurisdictions that adopt the IRC typically require a permit for roof replacement; roofing contractors must, however, be state-licensed under the Illinois Roofing Industry Licensing Act. Check local requirements before work begins.
Exemptions: No statewide rule — retaining-wall permitting is set by each Illinois municipality or county. The IRC R105.2 default many local codes adopt exempts retaining walls not over 4 feet in height unless the wall supports a surcharge (added load such as a slope, driveway, or structure above), in which case a permit and often engineering are required at any height. Verify the local amendment before building.
Exemptions: No statewide rule — shed permit thresholds are set by each Illinois municipality or county, and the state issues no permits (Illinois Capital Development Board). Many local codes follow IRC R105.2, which exempts one-story detached accessory structures with a floor area not exceeding 200 sq ft, but local amendments (commonly 100-200 sq ft) vary widely. Always confirm the threshold with the local building department.
Exemptions: No statewide permit rule — water-heater replacement permits are determined by each Illinois municipality or county. Statewide, the work itself must comply with the Illinois Plumbing Code and be performed by an Illinois-licensed plumber, but the Capital Development Board confirms the state issues no permits; jurisdictions adopting the IRC typically require a plumbing/mechanical permit for water-heater replacement since it is not exempt under IRC R105.2. Confirm with the local building department.
Building Department
Phone: 618-296-6200
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