Jefferson County, MO Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- Impervious coverage cap
- 80% of the development site
- Applies to
- industrially-zoned unincorporated development
- FAR limit
- per Table 5-2, Article V
- Residential buffer setback
- 50 feet from residential property
- Encouraged surfaces
- porous concrete or asphaltic paving
Summary
For industrially-zoned development in unincorporated Jefferson County, impervious surface (buildings, pavement) may cover up to 80% of the development site under the Industrial Design Standards, with porous paving encouraged for the remainder.
D. Site Coverage. 1. Maximum FAR (see Table 5-2 of Article V). The FAR shall be applied only to the area proposed for initial development, not to area left undeveloped and reserved for future expansion. 2. Impervious area coverage may extend up to eighty percent (80%) of the development site. Porous surfaces that allow storm water to infiltrate below the surface, such as porous concrete or asphaltic materials, are encouraged.
Full Breakdown
2400(D) of the Unified Development Order, part of Division 6 (Industrial Design Standards) within Article VII, governs site coverage for industrially zoned parcels in the unincorporated county. Two limits apply together: a maximum Floor Area Ratio (FAR) taken from Table 5-2 of Article V, applied only to the area actually proposed for initial development rather than land reserved for future expansion, and a separate impervious-area ceiling of 80% of the development site. The County encourages porous concrete or asphaltic surfaces that let stormwater infiltrate rather than run off, though the code does not mandate them.
2400(E)(1)-(2)). These industrial design standards apply only to developments in industrial zoning districts; they do not set a general residential or commercial lot-coverage cap for the rest of the county, which is governed by the setback and yard tables tied to each individual zoning district instead.
Violations & Fines
The UDO does not attach a standalone penalty to Section 400.2400. Because no specific penalty is provided, a coverage violation falls under the Code's General Penalty, Section 100.030: a fine of up to $1,000, imprisonment in the County Jail up to one year, or both, with each day the violation continues charged as a separate offense, prosecuted in Jefferson County Municipal Court.
Frequently Asked Questions
How much of an industrial lot in Jefferson County can be paved or built over?
Does the 80% impervious cap apply to residential lots too?
Is porous pavement required to meet the coverage limit?
Sources & Official References
Other rules in Jefferson County
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