How much does a building permit cost in O'Fallon, IL?

The minimum permit fee is $50. Fees are calculated as: Valuation-based and project-type flat fees. Plan check fee: Fire plan review $75+.

How do I apply for a building permit in O'Fallon, IL?

1. Download and complete the Building Permit Application. 2. Submit application with project costs and contractor information. 3. Plan review conducted by Building, Fire, and Engineering divisions. 4. Notification of approval and fee payment. 5. Permit issuance.

What work is exempt from building permits in O'Fallon, IL?

The following work is generally exempt: Painting, papering, tiling, carpeting, cabinets, and countertops; Retaining walls under 4 feet (no surcharge); Private sidewalks/driveways under 30 inches above grade; Reroofing (asphalt shingles) and window/door replacement (same opening size).

How do I schedule a building inspection in O'Fallon, IL?

Inspections can be scheduled via: (618) 624-4500, ext. 4.

City Building Permits

O'Fallon, IL - 2026 Building Permit Guide

How to apply for a building permit in O'Fallon, Illinois. Permit authority, application steps, fees, and inspection requirements.

Illinois St. Clair County Updated March 2026

Permit Authority

Incorporated City of O'Fallon.

Department: Community Development Department (Building & Inspections Division)
Address: 255 S. Lincoln Ave., O'Fallon, IL 62269
Phone: (618) 624-4500, ext. 4
Website: https://www.ofallon.org/169/Building-Inspections-Division

Online Permit Portal

Open Building Permit Forms

Platform: Downloadable PDF forms • Account required: No • Submission: In-person only

Application Process

Download and complete the Building Permit Application.
Submit application with project costs and contractor information.
Plan review conducted by Building, Fire, and Engineering divisions.
Notification of approval and fee payment.
Permit issuance.

Source: Community Development Department (Building & Inspections Division)

General Requirements

New construction, additions, structural alterations, electrical/plumbing/mechanical updates.

Required Documents

Application
Plans
Contractor information

Building code: 2021 IBC, 2021 IRC, 2020 NEC, Illinois Plumbing Code
Contractor requirements: Standard state requirements; local registration may apply.

Fees

Minimum permit fee: $50
Plan check fee: Fire plan review $75+
Permit fee formula: Valuation-based and project-type flat fees

Fees change. Verify current amounts at the official fee schedule.

Work That Does NOT Require a Permit

Painting, papering, tiling, carpeting, cabinets, and countertops
Retaining walls under 4 feet (no surcharge)
Private sidewalks/driveways under 30 inches above grade
Reroofing (asphalt shingles) and window/door replacement (same opening size)

Inspections

How to Schedule

(618) 624-4500, ext. 4 (phone)

Typical inspection sequence: Typical sequence: Footing, Rough-in, Final.

Additional Resources

Building code: 2021 IBC, 2021 IRC, 2020 NEC, Illinois Plumbing Code
Zoning information: View zoning info
O'Fallon Fire Rescue
License lookup guide: Illinois Contractor License Requirements
Contract template: Illinois Homeowner-Contractor Agreement
Illinois hub: Illinois Contractor License & Permit Hub

Information on this page was last verified: March 2026. Permit rules and fees change — confirm current requirements directly with the Community Development Department (Building & Inspections Division) before applying.

Frequently Asked Questions

O'Fallon Building Permit FAQ

Do I need a building permit in O'Fallon, IL?: New construction, additions, structural alterations, electrical/plumbing/mechanical updates.
How much does a building permit cost in O'Fallon, IL?: The minimum permit fee is $50. Fees are calculated as: Valuation-based and project-type flat fees. Plan check fee: Fire plan review $75+.
How do I apply for a building permit in O'Fallon, IL?: 1. Download and complete the Building Permit Application. 2. Submit application with project costs and contractor information. 3. Plan review conducted by Building, Fire, and Engineering divisions. 4. Notification of approval and fee payment. 5. Permit issuance.
What work is exempt from building permits in O'Fallon, IL?: The following work is generally exempt: Painting, papering, tiling, carpeting, cabinets, and countertops; Retaining walls under 4 feet (no surcharge); Private sidewalks/driveways under 30 inches above grade; Reroofing (asphalt shingles) and window/door replacement (same opening size).
How do I schedule a building inspection in O'Fallon, IL?: Inspections can be scheduled via: (618) 624-4500, ext. 4.

Need help with your project?

Navigating permits in O'Fallon can be complicated.

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Important: This page is an educational resource provided by jaspector.com. It is not legal advice, and it does not substitute for official guidance from the permit authority listed above. Permit requirements, fees, and processes change frequently. Always verify current requirements directly with the issuing department before beginning any construction project. Use of this page does not create an attorney-client relationship. Jaspector assumes no liability for any outcomes arising from reliance on this information.

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