ADU Permit Requirements in Wilsonville, IL
Macoupin County does not issue building permits inside incorporated villages (county permits cover only unincorporated areas, and only new construction with septic at $100 flat). Illinois has no statewide residential building code; counties and municipalities adopt their own. Wilsonville has no village website and no published building permit ordinance. The phone number (217) 999-6123 was last verified in 2011. State-mandated layers still apply regardless of local code: Illinois State Plumbing Code (IDPH-licensed plumbers), 2021 Illinois Energy Conservation Code, and electricians regulated by local ordinance. All rules for Wilsonville should be treated as IRC 2021 baseline guidance only; residents must call the village office or visit the municipal building to confirm before starting any work. Macoupin County contact for reference: https://macoupincountyil.gov/whats-happening-now/licenses-permits-zoning-information/, (217) 854-3214 ext. 918.
Wilsonville does not publish a building permit process online and we could not verify a current building authority. The guidance below is based on baseline IRC code (the most commonly adopted residential code) plus state-mandated layers. Before starting any work, call the village office at (217) 999-6123 to confirm what permits and inspections actually apply.
By Joey, Founder · Last verified April 18, 2026 · How we research →
When you need a ADU permit in Wilsonville
Under 2021 IRC, a detached accessory dwelling unit (ADU) typically requires building, plumbing, electrical, and mechanical permits. Most importantly, ADUs are often restricted by local zoning, which Wilsonville may or may not allow. Illinois requires state-licensed plumbers (IDPH) and electricians for trade work even in unincorporated/uncoded areas. Verify with village before starting.
Under 2021 IRC, an attached ADU (in-law suite, garage conversion with kitchen) typically requires building, plumbing, and electrical permits. ADUs are often restricted by local zoning. Illinois requires state-licensed plumbers (IDPH) and electricians for trade work even in unincorporated/uncoded areas. Verify with village before starting.
ADU Permit Costs: Wilsonville vs. Nearby
| City | Estimated Fee |
|---|---|
| Wilsonville | N/A |
| Chicago | $500 – $5,000 |
| Aurora | $500 – $5,000 |
| Joliet | $500 – $5,000 |
Fees shown are estimates based on local building code data. Actual fees may vary based on project scope and valuation. See all Wilsonville permit costs →
Zoning Considerations
ADU regulations vary dramatically by state and city. Many states (CA, OR, WA) have preemption laws that override local zoning restrictions. Check both state law and local zoning before designing.
Estimated Project Timeline in Wilsonville
Here's a typical timeline for a adu project in Wilsonville, IL:
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Frequently Asked Questions
Contact Wilsonville's building department for current ADU permit fee information. Fees typically vary based on project scope and valuation.
It depends on the specifics of your project. Some smaller ADU projects may be exempt from permit requirements, while larger ones typically require a permit. Use our free lookup tool to check your specific situation.
Working without a required permit in Wilsonville can result in fines, stop-work orders, being required to remove completed work, and complications when selling your home. It's always best to check first.
Contact Wilsonville's building department for current processing times. Timelines vary based on project complexity and whether plan review is required.
Learn More About ADU Permits
Read our complete guide covering permit requirements, costs, common exemptions, and the application process.
Read ADU Guide →