Building Permits in O'Fallon

Building permits in O'Fallon are administered by the City Building Division, which performs plan review and inspections for residential and commercial construction.

Current codes

O'Fallon adopted the 2021 International Building Code, with local amendments, by Ordinance 7133 effective September 12, 2024. The city also publishes its adopted code set and amendments for other construction disciplines. Professional-design and seal requirements depend on the project and applicable code; this guide does not treat a seal as universal for every permit.

Applications and permits

The city requires residential permits for new homes, decks, sheds, pools, basement finishes, additions and major alterations. Commercial permits are required for new commercial projects, alterations and additions. Applications and inspection scheduling are available through CitizenServe.

Fees

Permit fees depend on the project and the city's current fee schedule. Because no single fee represents all building permits, applicants should use the current city schedule/portal rather than a generic estimate.

Inspections and occupancy

The Building Division performs required inspections. The city says inspections scheduled through CitizenServe are typically completed the next day; rental-occupancy inspections may require two days' notice depending on when the request is received. These are city-published operating expectations, not a guarantee for every construction inspection.

Official sources

• City of O'Fallon Building and Permits: https://www.ofallon.mo.us/building-permits
• O'Fallon Code, Building Code adoption: https://ecode360.com/27597304

Disclaimer: Verify current code amendments, permit category, fees, professional-design requirements, inspections, and occupancy requirements with the O'Fallon Building Division before filing or beginning work.