St. Tammany Parish, LA Environmental Rules: Flood Zones (2026)

Sec. S. 38:84 and readopted by Ordinance No. 25-5795 in August 2025. Subsection C establishes that a Floodplain Development Permit is required to ensure conformance with the ordinance, and no structure or land may be located, altered or have its use changed in an area of special flood hazard without full compliance. The Chief Building Official serves as the parish Floodplain Administrator, reviewing every permit application against the current FEMA Flood Insurance Study and Flood Insurance Rate Maps for the parish. Subsection E's specific standards require new construction and substantial improvement of residential structures to have the lowest floor, including any basement, at or above the base flood elevation plus 12 inches, certified by a registered engineer, architect or land surveyor; nonresidential structures must meet the same elevation or be floodproofed and certified watertight to that height.

Manufactured homes, recreational vehicles and accessory structures each carry their own elevation, anchoring or size limits (accessory structures are capped at 600 square feet in A zones and 100 square feet in V zones), and encroachments, including fill and new construction, are prohibited outright within the adopted regulatory floodway unless engineering analysis shows no increase in flood levels. Variances go to the parish Board of Adjustments, with any denial appealable to the 22nd Judicial District Court.