Jefferson County, AL Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- Max impervious, Lower Slope Zone
- 15% (15-24.9% grade)
- Max impervious, Upper Slope Zone
- 10% (25-34.9% grade)
- Max disturbed area
- 30% LSZ / 20% USZ
- Triggers when
- Natural slope ≥15%
- Adopted
- October 9, 2025
- Variance authority
- County Board of Adjustment
Summary
In Jefferson County's Slope Zone Overlay District, land with a natural slope of 15% or more, impervious surface is capped at 15% of the lot in the Lower Slope Zone and just 10% in the Upper Slope Zone. Development in the steepest Hazard Zone is barred outright without certified geotechnical clearance.
Applicability. The SZOD shall apply to any land within unincorporated Jefferson County where the natural slope equals or exceeds 15%, as delineated by certified topographic surveys using a 25-foot vertical span. ... Development Standards Table: Standard / LSZ / USZ - Min. lot size 25,000 sq ft / 40,000 sq ft; Max. impervious surface 15% / 10%; Max. disturbed area 30% / 20%; Max. building height 35 ft (single-family) / 30 ft (single-family); Min. setbacks 15 ft (side), 25 ft (rear), 25 ft (front) / 15 ft (side), 25 ft (rear), 25 ft (front).
Full Breakdown
Adopted October 9, 2025 as part of the Zoning Regulations, Section 1504 creates the Slope Zone Overlay District (SZOD) to control erosion, stormwater runoff and slope instability on hillside land anywhere in unincorporated Jefferson County where the natural slope equals or exceeds 15%, as measured by certified topographic surveys over a 25-foot vertical span. 9% grade and tightens impervious surface to 10% and disturbed area to 20%, with a 40,000-square-foot minimum lot; the Hazard Zone covers 35% grade or greater, or land with known geotechnical instability, landslide risk or subsurface hazards, and bars any development there without certified geotechnical clearance.
Building height in both regular zones is capped at 35 feet (Lower) or 30 feet (Upper) for single-family homes, with 15-foot side, 25-foot rear and 25-foot front setbacks in both. 5 factor of safety. Variances from these limits are granted only on a showing of hardship unique to the parcel, approved by the County Board of Adjustment; the Jefferson County Planning Department enforces the district through site plan review and the standard permit process, and all subdivisions within SZOD must submit slope maps and geotechnical assessments before plat approval.
Violations & Fines
SZOD compliance is enforced by the Jefferson County Planning Department through site plan review and the ordinary building-permit process; a subdivision or building permit will not be certified within the overlay without the required geotechnical certification. Beyond that permit gate, violating any Zoning Regulations provision, including the SZOD's impervious-surface and disturbed-area limits, is a class B misdemeanor under the Administration and Enforcement article, with each day of continued violation counted as a separate offense and a written cease-and-desist notice required before prosecution.
Frequently Asked Questions
What impervious surface limit applies on hillside lots in Jefferson County?
Can I build on a lot with a 40% slope?
Is there a general lot-coverage cap outside slope zones?
How do I get a variance from the SZOD limits?
Sources & Official References
Other rules in Jefferson County
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