Delaware County, PA Environmental Rules: Flood Elevation Requirements (2026)

Section 62-12, the chapter's definitions article, fixes "regulatory flood elevation" as the one-hundred-year flood elevation plus a freeboard safety factor of one and one-half feet; "freeboard" itself is defined as a safety factor expressed in feet above a flood level. The one-hundred-year flood is the flood with a one-percent chance of occurring in any given year, as delineated in the federal Flood Insurance Studies covering Delaware County municipalities. That elevation standard runs through the chapter's design rules: §62-10C requires any residential site outside a floodway to be elevated to the regulatory flood elevation before it can be used, with fill extending at least 15 feet beyond the structure.

Section 62-10D lets the County Planning Commission approve commercial or industrial sites below the regulatory elevation only if the developer floodproofs to that same height. Section 62-11D requires public sanitary sewer systems in a designated floodplain district to be floodproofed up to the regulatory flood elevation, and bars soil-absorption sewage systems where groundwater or flooding would defeat them. Section 62-11E applies the identical floodproofing floor to public and private water systems, and §62-11F extends it to every other public or private utility, including gas and electric service.

Like the rest of Chapter 62, this standard applies only in Delaware County municipalities of the First or Second Class that have no floodplain-compliant subdivision ordinance of their own on file with the County Planning Department, per §62-5; where a municipality has adopted and filed its own compliant ordinance, that local freeboard standard controls instead.