Building Safety in O'Fallon, MO (2026)
4 verified building safety rules for O'Fallon, Missouri, sourced directly from the municipal code and official government pages.
Verified from official government sources
Fire Sprinkler Requirements
O'Fallon's adopted Residential Code requires automatic fire sprinklers in townhouses under state law, but for one- and two-family dwellings a builder only has to offer the buyer the option to add sprinklers at the buyer's cost. No city rule can force a single-family buyer to accept or decline that option.
O'Fallon Residential Fire Sprinkler Rule
Some RestrictionsO'Fallon Code § 500.340 (IRC §§ R313.1, R313.2)
R313.1 Townhouse automatic fire sprinkler systems. An automatic sprinkler system shall be installed in townhouses, in accordance with Section 67.281 of the Missouri Revised Statutes. Exception: An automatic sprinkler system shall not be required where additions or alterations are made to existing townhouses that do not have an automatic sprinkler system installed. R313.2 One- and two-family dwe...
Building Permits
Any alteration to real property in O'Fallon, including driveways, fences, additions and other regulated building activity, requires a permit before construction begins. The Building Official enforces this rule, and the adopted 2021 International Building Code exempts only specific minor work, like low retaining walls and finish work, from that requirement.
O'Fallon Building Permit Requirement
Some RestrictionsO'Fallon Code § 500.390
Any person, firm or corporation making an alteration to real property within the City limits of O'Fallon, Missouri, including, but not limited to, driveways, fences, additions to homes and businesses, and any building activity regulated by City ordinance or Code, who fails to obtain the proper permits prior to commencing construction shall be in violation of this Chapter.
Electrical Permits
O'Fallon has adopted the 2020 National Electrical Code as its Electrical Code, covering the design, installation and repair of electrical systems citywide, and requires a permit for that work. Every contractor who wants to do electrical work in the city must first pass an exam and hold an active license from St. Charles County or the State of Missouri.
O'Fallon Adopted Electrical Code (NEC 2020)
Some RestrictionsO'Fallon Code §§ 500.190, 500.200 (NEC § 90.1(E))
That certain document, ... being marked and designated as the National Electric Code, 2020 Edition, as published by the National Fire Protection Agency, be and is hereby adopted as the Electrical Code of the City of O'Fallon, in the State of Missouri, for regulating and governing the design, construction, quality of materials, erection, installation, alteration, repair, location, replacement, a...
Plumbing Permits
O'Fallon has adopted the 2021 International Plumbing Code, including Appendix E, as its Plumbing Code, governing plumbing system design, installation, alteration and repair citywide and requiring a permit and fee for that work. Every plumbing or drainlaying contractor must first pass an exam and hold an active license from St. Charles County before working in the city.
O'Fallon Adopted Plumbing Code (IPC 2021)
Some RestrictionsO'Fallon Code §§ 500.230, 500.240 (IPC § 103.90)
That certain document, ... being marked and designated as the International Plumbing Code, 2021 Edition, including Appendix E, as published by the International Code Council, be and is hereby adopted as the Plumbing Code of the City of O'Fallon, in the State of Missouri, for regulating and governing the design, construction, quality of materials, erection, installation, alteration, repair, loca...
Looking for St. Charles County county-wide rules?
County ordinances apply to unincorporated areas and may supplement O'Fallon city rules.
Building Safety in St. Charles County →