City Building Permits
O'Fallon, MO - 2026 Building Permit Guide
How to apply for a building permit in O'Fallon, Missouri. Permit authority, application steps, fees, and inspection requirements.
Permit Authority
Applies within the City of O'Fallon municipal limits in St. Charles County
- Department
- City of O'Fallon Planning and Development Department
- Address
- 100 North Main St., O'Fallon, MO 63366
- Phone
- 636-379-5594
- Website
- https://www.ofallon.mo.us/
Online Permit Portal
Platform: City website permit services; exact public portal brand not clearly identified on the landing pages reviewed • Account required: No • Submission: In-person only
Additional resources:
Application Process
- Verify permit type with Planning and Development and check for zoning, engineering, or right of way reviews
- Prepare permit application, plans, and contractor information
- Submit through the City permit process
- City completes review and returns comments if revisions are required
- Fees are paid after approval
- Permit is issued and inspections are scheduled with the City
Typical processing time: Not clearly posted on the public pages reviewed
Source: City of O'Fallon Planning and Development Department
General Requirements
New construction, additions, remodels, accessory structures, many trade permits, and other regulated work under city code
Required Documents
- When a permit is required: New construction, additions, remodels, accessory structures, many trade permits, and other regulated work under city code
- Required documents: Permit form, plans/specifications, site plan or plat information as applicable, contractor data, and project valuation
- Permit validity/expiration: Not clearly posted on the public pages reviewed
- Owner-builder rules if available: Not clearly posted on the public pages reviewed
- Contractor license requirements: City administers contractor licensing/registration tied to permit issuance
- Building code adopted: City enforces locally adopted construction codes; exact edition should be confirmed from city ordinance before application
- Permit validity
- Not clearly posted on the public pages reviewed
- Building code
- City enforces locally adopted construction codes; exact edition should be confirmed from city ordinance before application
- Owner-builder
- Not clearly posted on the public pages reviewed
- Contractor requirements
- City administers contractor licensing/registration tied to permit issuance
Fees
- Minimum permit fee
- Not clearly posted on the public pages reviewed
- Plan check fee
- Not clearly posted on the public pages reviewed
- Permit fee formula
- Mix of valuation-based and permit-type specific fees
- Reinspection fee
- Not clearly posted on the public pages reviewed
- Payment note
- Paid through the City permit process
Fees change. Verify current amounts at the official fee schedule.
Work That Does NOT Require a Permit
Contact the City of O'Fallon Planning and Development Department to confirm whether your project requires a permit before starting work.
Inspections
How to Schedule
- Through the City after permit issuance ()
- Inspection hours
- Not clearly posted
Typical inspection sequence: Footing/foundation, rough framing and trades, then final inspections
Additional Resources
- Building code: City enforces locally adopted construction codes; exact edition should be confirmed from city ordinance before application
- Zoning information: View zoning info
- ofallon.mo.us
- gis5.ofallon.mo.us
- License lookup guide: Missouri Contractor License Requirements
- Contract template: Missouri Homeowner-Contractor Agreement
- Missouri hub: Missouri Contractor License & Permit Hub
Information on this page was last verified: March 2026. Permit rules and fees change — confirm current requirements directly with the City of O'Fallon Planning and Development Department before applying.
Frequently Asked Questions
O'Fallon Building Permit FAQ
- Do I need a building permit in O'Fallon, MO?
- New construction, additions, remodels, accessory structures, many trade permits, and other regulated work under city code
- How much does a building permit cost in O'Fallon, MO?
- The minimum permit fee is Not clearly posted on the public pages reviewed. Fees are calculated as: Mix of valuation-based and permit-type specific fees. Plan check fee: Not clearly posted on the public pages reviewed.
- How do I apply for a building permit in O'Fallon, MO?
- 1. Verify permit type with Planning and Development and check for zoning, engineering, or right of way reviews 2. Prepare permit application, plans, and contractor information 3. Submit through the City permit process 4. City completes review and returns comments if revisions are required 5. Fees are paid after approval 6. Permit is issued and inspections are scheduled with the City
- How long does it take to get a building permit in O'Fallon, MO?
- Typical processing time is Not clearly posted on the public pages reviewed.
- What work is exempt from building permits in O'Fallon, MO?
- The following work is generally exempt: No consolidated public exemption list was located on the public pages reviewed.
- How do I schedule a building inspection in O'Fallon, MO?
- Inspections can be scheduled via: Through the City after permit issuance.
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