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

Light Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Max size without permit
12 square feet
Illumination
Not allowed, must be non-illuminated
Permit needed above limit
Sign permit under §400.4230
Comparable nameplate limit
2 square feet (§400.4250(A)(2))
Governing section
UDO §400.4250(A)(7)

Summary

Jefferson County exempts a home occupation sign from its usual sign-permit process under UDO Section 400.4250(A)(7), as long as it is non-illuminated and no larger than 12 square feet. Exceed that size or light it up, and the sign needs a permit under Section 400.4230 like any other commercial sign.

These county ordinances apply to unincorporated areas of Jefferson County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

The following signs do not require the issuance of a permit from the County... Signs for home occupations provided that they are non-illuminated and do not exceed twelve (12) square feet in area.

View official code

Full Breakdown

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. 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. 4240, measured from natural grade unaffected by fill or grading. 2890.

Violations & Fines

Posting a home business sign larger than 12 square feet, illuminating it, or erecting it without the required sign permit is a UDO violation under Section 400.140, enforced by County Code Enforcement. The Director can order the sign removed or brought into compliance; failing to comply is a misdemeanor punishable by up to a $1,000 fine, up to one year in jail, or both.

Frequently Asked Questions

How big can my home business sign be in Jefferson County?
Up to 12 square feet without needing a sign permit, as long as the sign is not illuminated. Section 400.4250(A)(7) exempts a home occupation sign of that size from the County's usual sign-permit process, which otherwise requires Planning Division approval and a building permit under Section 400.4230.
Can I put up a lighted sign for my home business?
Not under the permit-free exemption. Section 400.4250(A)(7) only exempts a home occupation sign from permitting if it is non-illuminated; lighting it, or exceeding the 12-square-foot cap, pulls the sign out of the exemption and requires a sign permit reviewed under Section 400.4230 before it can go up.

Sources & Official References

Other rules in Jefferson County

Fence Regulations: Height LimitsSome RestrictionsParking Rules: RV & Boat ParkingSignificant RestrictionsZoning & Home Occupation PermitsSome RestrictionsCustomer Traffic RestrictionsSome RestrictionsHome DaycareSome RestrictionsNoise Ordinances: Decibel LimitsSignificant RestrictionsParking Rules: Loading ZonesSome RestrictionsParking Rules: Driveway RulesSome RestrictionsFence Regulations: Retaining WallsSome Restrictions

All Jefferson County rules

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