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§ IL St. Clair County
City building permits

City of O'Fallon

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

Code adoption
2021 IBC, 2021 IRC, 2020 NEC, Illinois Plumbing Code
Min. permit fee
$50
Last verified
April 2026
On this page 6
§ 01

Permit authority

Community Development Department (Building & Inspections Division)

Street address
255 S. Lincoln Ave., O'Fallon, IL 62269
Phone
(618) 624-4500, ext. 4
Coverage
Incorporated City of O'Fallon.
Online portal
Building Permit Forms
Downloadable PDF forms
Website
Department website
§ 02

When a permit is required

Permit triggers and exempt work for O'Fallon

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

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

Source: Community Development Department (Building & Inspections Division) ↗

§ 03

Application process

Application → plan check → issuance → inspection → final

  1. 01
    Download and complete the Building Permit Application.
  2. 02
    Submit application with project costs and contractor information.
  3. 03
    Plan review conducted by Building, Fire, and Engineering divisions.
  4. 04
    Notification of approval and fee payment.
  5. 05
    Permit issuance.

Source: Community Development Department (Building & Inspections Division) ↗

§ 04

Fee schedule

O'Fallon building permit fees

Fee type
Amount
01
Minimum permit fee
$50
02
Plan check fee
Fire plan review $75+
03
Permit fee formula
Valuation-based and project-type flat fees

Fees change periodically. Confirm at the official fee schedule ↗ before budgeting.

§ 05

Required inspections

Scheduling and sequence

How to schedule
  • (618) 624-4500, ext. 4 (phone)

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

Source: Community Development Department (Building & Inspections Division) ↗

§ 06

Frequently asked

Common questions about O'Fallon permits

01 Do I need a building permit in O'Fallon, IL? ▸
New construction, additions, structural alterations, electrical/plumbing/mechanical updates.
02 How much does a building permit cost in O'Fallon, IL? ▸
Building permit fees in O'Fallon, IL are set by the local building department and vary by project type and valuation. The minimum permit fee is $50. Fees are calculated as: Valuation-based and project-type flat fees. Plan check fee: Fire plan review $75+.
03 How do I apply for a building permit in O'Fallon, IL? ▸
To apply for a building permit in O'Fallon, IL, follow these steps: 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.
04 What work is exempt from building permits in O'Fallon, IL? ▸
Not all construction work requires a permit 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). When in doubt, confirm with the local building department before starting work.
05 How do I schedule a building inspection in O'Fallon, IL? ▸
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in O'Fallon, IL via: (618) 624-4500, ext. 4.
last verified April 2026 source Community Development Department (Building & Inspections Division) ↗ entry id permits/illinois/st-clair/o-fallon
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Educational reference. Permit rules and fees change — confirm current requirements directly with Community Development Department (Building & Inspections Division) before applying. Jaspector is not legal advice.

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