Norman, OK Environmental Rules: Flood Elevation Requirements (2026)

NCC Section 36-533(e)(3)a spells out the fill and elevation standard for residential structures, site-built and manufactured alike: the lowest floor, including the basement, ductwork, and mechanical and electrical equipment such as furnaces, water heaters, and air conditioners, must sit at least two feet above the base flood elevation. The supporting fill itself cannot be lower than one foot above BFE and must extend at least fifteen feet beyond the structure and any attached utility or sanitary facilities. Manufactured homes placed in Zone A get the identical two-foot freeboard standard plus anchoring against flotation, collapse, or lateral movement, using methods like over-the-top or frame ties to ground anchors.

In the A-2, Rural Agricultural District, that comes with a minimum ten-acre lot size (or a legal lot of record before February 25, 1997), rising to 20 acres inside the Ten Mile Flat Conservation Area under NCC 36-512. Nonresidential construction faces the same fill-and-two-foot elevation rule, with an alternative floodproofing path if a registered professional engineer certifies to the Director of Public Works that the design meets the chapter's standards. The Code defines freeboard, in its section 36-533 definitions, as a safety factor above the calculated flood level that compensates for unknowns such as wave action, bridge openings, and watershed urbanization.

Agricultural buildings not meant for human occupancy can seek a variance from the two-foot fill requirement from the Floodplain Permit Committee if there is no adverse off-site impact and utilities are floodproofed.