Madison County, IL Building Safety: Building Permits (2026)

Madison County's zoning code sets the building-permit trigger for accessory structures at 200 square feet: anything smaller is exempt from the permit itself, per § 93.007(B)'s definition of ACCESSORY BUILDING or STRUCTURE, but it must still satisfy the accessory-structure setback standards in § 93.051. Above that threshold, a permit application must go to the county before work starts. Separately, Chapter 90's Building Permits provisions govern how issued permits are handled: § 90.01 requires the County Board to forward a copy of any building or occupancy permit to both the Township Assessor and the County Assessor within 15 days of issuance, including the property's complete legal description and, where one exists, its real estate index number under 35 ILCS 200/1 et seq. § 90.02 gives the County Board authority to discontinue issuing building permits within a prescribed area if it determines that further permits would endanger public health or welfare; before doing so the Board must publish notice once in a newspaper of general circulation describing the decision, the affected area and the hazard driving it.

Permits for construction in unincorporated territory are issued under the codes the county has adopted by reference in § 90.16, including the 2012 International Building Code and 2012 International Residential Code, and are handled through the county's Planning and Development / Building and Zoning Department rather than any city hall, since incorporated cities and villages like Edwardsville and Alton issue their own permits inside their limits.