Local building department guide · Updated 2026-07-30
O'Fallon Building Department | Permits, Inspections & Contact
Use this guide to find the official O’Fallon, Missouri Building Division, start a permit application, search permit records, schedule an inspection, and locate the correct zoning or plan review contact.
Start here
Quick actions
Apply for a building permit
Review the typical application path and prepare your project details.
See permit stepsTrack or search permits
Find O'Fallon permit search resources and application status links.
Search permitsSchedule a building inspection
Learn what to have ready before requesting your next inspection.
Schedule inspectionOther portal login
Open the department's official online services and permit portal.
Open portalThe City of O’Fallon Building Division performs plan review and inspections for new residential and commercial properties, administers adopted building codes, and coordinates permit and occupancy requirements inside O’Fallon city limits. O’Fallon is in St. Charles County, but the city’s building permit process is municipal. The city also warns that several independent fire protection districts serve O’Fallon and may require separate approvals; contact the relevant district when the project requires it.
O’Fallon building permits and CitizenServe
O’Fallon requires permits for new buildings, additions, remodels, repairs, and regulated electrical, mechanical, and plumbing work. Residential rental occupancy permits are required before occupying a rental unit. The city’s CitizenServe portal allows users to register, apply for permits, submit documents, pay fees, view review status, manage projects, and schedule inspections. Use the city’s permit guides to confirm the submittal requirements for decks, sheds, pools, basements, reroofing, signs, and other common projects.
Inspections, code compliance, and occupancy
Schedule inspections through the CitizenServe portal. The city says standard inspection requests are typically completed the next day, while rental occupancy inspections may require two days’ notice depending on when the request is received. Building permits and rental occupancy approvals must be completed before the applicable space is occupied; separate fire-district inspection or permit requirements may also apply.
Zoning and plan review
The city’s Building Division and Engineering and Plan Review Group coordinate review of building, site-development, floodplain, stormwater, utility, and planning-related work. Check O’Fallon’s zoning and district map and confirm whether the project requires planning, engineering, land-disturbance, driveway, sign, or fire-district approvals in addition to the building permit.
Official contact information
The Building Division is located on the second floor of O’Fallon Municipal Centre at 100 North Main Street, O’Fallon, Missouri 63366. The main Building Division line is (636) 379-5660. The city’s general municipal phone is (636) 240-2000. Use the official CitizenServe portal for applications, permit status, payments, and inspection scheduling.
Permit process
How to Apply for a O'Fallon Building Permit
Confirm the project scope
Identify the work, property address, project valuation, and whether plans are required.
Prepare your documents
Gather plans, owner and contractor details, site information, and any zoning approvals.
Submit and monitor
Submit through the department’s stated process, pay fees, and watch for review comments.
Field work & closeout
Building Inspections & Code Compliance in O'Fallon
Most permitted work must remain accessible for inspection at defined stages. Before scheduling, check your permit record for the required inspection sequence and make sure the site is safe and ready. Final inspections can be especially important for code compliance and a certificate of occupancy.
Helpful preparation
Keep the permit card or approval number available, confirm the property address, and ask the official office about lead times or reinspection fees.
Planning & review
Zoning and Plan Review Requirements
A building permit is not always the only approval your project needs. Zoning guidelines may affect use, setbacks, height, parking, signage, or lot coverage. Residential and commercial building permits can also follow different plan review tracks, so confirm the correct path before investing in a full plan set.
For a project in O'Fallon, start with the official department below and ask which zoning, planning, conservation, or fire review approvals apply to your address.
Keep this handy
Official Contact Information
| Department | O’Fallon, Missouri Building Division |
|---|---|
| Phone | (636) 379-5660 |
| Address | 100 North Main Street, O’Fallon Municipal Centre, O’Fallon, MO 63366 |
| Official website | https://ofallon.mo.us/building-permits |
| Last verified | 2026-07-30 |
Official source pages used for this guide
These links were checked on 2026-07-30. Requirements, fees, office hours, and portal addresses can change; use the official source as the final authority.