O'Fallon, MO Sign Regulations: Window Signs (2026)
Key Facts
- Coverage cap
- 20% of window or window series
- Permit needed
- None, if under the cap
- Exempt items
- Unaffixed merchandise/product displays behind glass
- Reclassification
- Non-painted exterior signage becomes a wall sign
- Cure period
- Immediate for temporary window signs
Summary
O'Fallon lets businesses put signs in their windows without a permit, but Section 410.120(A)(14) caps them at twenty percent of the window, or of a series of contiguous windows. Go over that, and City staff can order the display down or treat it as an unpermitted wall sign.
Window Signs And Displays. Window signs shall not cover more than twenty percent (20%) of the window or a series of contiguous windows. Merchandise, pictures or models of products that are not affixed or touching the window but are visible through the window, that are not intended to be part of the signage, are not considered signs. Any sign placed on the outside of a window, except for individual letters painted directly onto the window, shall be considered a wall sign.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4860992; v58 updated 2026-05-14; through 05-14-2026).
Full Breakdown
120, the chapter listing signs allowed in every zoning district without needing a sign permit at all, provided they don't exceed the twenty percent coverage limit for the window or for a run of contiguous windows treated as one unit. The code draws a careful line around what even counts as a sign: merchandise, pictures or product models that sit behind the glass but are not affixed or touching it, and are not meant as signage, do not count toward the twenty percent at all.
5% for larger ones. 120(A)(13), and sandwich board signs near an entrance are regulated under a different subsection entirely, so a business layering several of these together needs to check each type's own limit rather than assuming the 20% window rule covers all of them.
Violations & Fines
A window display over twenty percent coverage, or an unpainted sign on the glass exterior mistreated as exempt when it is really a wall sign, is enforced the same as any other sign violation under Section 410.190: written notice to the owner or premises manager, immediate compliance required for a temporary display, and on conviction a fine of up to $500.00, up to ninety days' imprisonment, or both, with each day of continued violation a separate offense.
Frequently Asked Questions
How much of my storefront window can I cover with signage in O'Fallon?
Do product displays in my window count toward the 20% limit?
What if I put a decal on the outside of my window instead of inside?
Sources & Official References
Other rules in O'Fallon
Compare O'Fallon to another location·View the Missouri sign regulations overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.