Jefferson County, MO Home Business: Signage Rules (2026)

Jefferson County exempts a limited category of signs from its Article XIII sign-permit requirement, and a home occupation's identification sign is one of them. Section 400.4250(A)(7) lets a home-based business post a sign without applying for a sign permit or a building permit, so long as the sign is not illuminated and does not exceed 12 square feet in area, larger than a private residence's plain nameplate (capped at 2 square feet under Subsection (A)(2)) but well below the size allowed for commercial signage. Exceeding either limit, lighting the sign, or exceeding the permit-free category entirely moves the installation out of the exemption, and the operator must then obtain a sign permit under Section 400.4230, approved by the Planning Division with a building permit issued by Code Enforcement; the sign must still satisfy the height limit of its zoning district under Section 400.4240, measured from natural grade unaffected by fill or grading.

Article XIII states its purpose is to balance free expression with avoiding visual clutter that threatens traffic and pedestrian safety, so the County treats an oversized or illuminated home-business sign as inconsistent with residential character even where the underlying home occupation itself is otherwise permitted under Section 400.2890.