Jefferson Parish, LA Environmental Rules: Flood Elevation Requirements (2026)

The freeboard standard lives in Sec. 2, Slab/floor elevation regulations, inside the parish's Lot Grade and Building Elevation Regulations division, and it applies on top of whatever chapter 14 of the Code separately requires for floodplain management. For residential construction, the top of slab or floor must be at or above the base flood elevation shown on FEMA's Flood Insurance Rate Map for the lot, but the parish adds its own floor: regardless of what the FIRM shows, the slab can never sit less than eighteen inches above the crown of the adjacent street.

for elevation to the base flood elevation, provided all utility and sanitary equipment is included in that floodproofing. The parish carves out small accessory buildings entirely: structures of two hundred square feet or less used only for parking or storage, with no utilities run to them, do not have to meet either elevation standard. Anything built in a V zone, FEMA's highest-hazard coastal flood designation, must go further than a slab elevation: a Louisiana State Registered Architect or Civil Engineer has to certify that the structure is securely attached to adequately anchored pilings or columns, and the companion section, Sec. 1, extends the same base-flood-elevation floor to the lowest horizontal structural member of pier and chain-wall foundations used under manufactured homes.