Lower Paxton, PA Environmental Rules: Flood Elevation Requirements (2026)

Section 108-23 of the Lower Paxton Township Code sets the elevation rules for every identified floodplain area. For a residential structure in an AE, A1-30 or AH Zone, the lowest floor, including a basement, must sit up to or above the regulatory flood elevation. In an A Zone where the Flood Insurance Rate Map shows no base flood elevation, the same floor rule applies, and the elevation is found under § 108-19C(2)(b): when no other information is available, the BFE is taken from a point on the boundary of the identified floodplain area nearest the construction site.

In an AO Zone the lowest floor must be at or above the highest adjacent grade at least as high as the depth number printed on the FIRM. The definitions in § 108-35 set the regulatory flood elevation equal to the base flood elevation (BFE), the water surface elevation of a flood with a 1% or greater chance of occurring in any given year. Nonresidential buildings have a second route: elevate the lowest floor, or design the enclosed space below the regulatory flood elevation to be watertight with walls substantially impermeable to water and structural components that resist hydrostatic and hydrodynamic loads and buoyancy.

Fully enclosed space below the lowest floor, crawl spaces included, needs automatic floodwater openings: at least two openings with a net total area of not less than one square inch for every square foot of enclosed space, with the bottom of every opening no higher than one foot above grade. Accessory structures need not be elevated but cannot exceed 1,000 square feet of floor area, cannot be used for habitation, and cannot contain sanitary facilities. A permit is required before any construction or development under § 108-8. Improvements costing 50% or more of a structure's market value count as a substantial improvement under § 108-31C and must meet the full chapter.