Alachua County, FL Environmental Rules: Flood Elevation Requirements (2026)

Section 406.57(d)'s one-foot freeboard applies on top of whatever FEMA base flood elevation (BFE) governs the site, and the county allows it to be met with an open foundation, pilings or a stem wall with flood openings built to § 406.57(k). The same one-foot-above-BFE standard extends to utility systems: septic tanks and drain fields must sit outside the ten-year floodplain, and sewage, water, electrical and communications utilities must be designed to resist floodwater infiltration up to one foot above BFE (§ 406.57(e)). Manufactured and mobile homes get their own elevation rule, the bottom of the frame must clear the Florida Building Code's Residential Section R322.2 or R322.3 elevation, and pad-mounted mobile homes on compacted fill or pilings must have their lowest floor at least one foot above BFE (§ 406.57(n)).

For fill placed within a stream basin or depression basin, utility equipment and ductwork must sit at or above one foot over BFE, or three feet above natural grade where no BFE has been established (§ 406.57(c)). Roads serving as the sole ingress and egress to a subdivision or single-family home must be elevated one foot above the 100-year floodplain (§ 406.57(j)). Flood openings for enclosed areas below the lowest floor need at least one square inch of net opening per square foot of enclosed area, with the bottom of each opening no higher than one foot above grade (§ 406.57(k)).