Sussex County, DE Environmental Rules: Flood Zones (2026)

Sussex County faces some of the highest flood exposure in Delaware. Sea levels along the Delaware coast have risen at roughly twice the global average, with up to 15 inches of increase over the past century according to DNREC, and DNREC's Climate Action Plan projects an additional one to one and a half feet of sea-level rise by midcentury and as much as four to six feet by 2100. Approximately 15% of Sussex County residents live in a floodplain and more than one-fifth of all properties are within identified flood plains. FEMA Flood Insurance Rate Maps (FIRMs) for Sussex County were updated and adopted by the County in January 2015 (Ordinance No. 2384) and affirmed by FEMA in March 2015. The maps identify Zones VE (coastal high-hazard with wave action) along the Atlantic oceanfront, AE (1% annual chance flood with established Base Flood Elevation) along bays and tidal tributaries, AO/AH (shallow flooding), and Zone X (areas of reduced or minimal flood hazard). Floodplain regulation in unincorporated Sussex County is consolidated in Article XVIII ("Flood-Prone Districts") of the County Zoning Code; before Ordinance 2384 these provisions were scattered across Sections 115-4, 115-189 and the prior Article XVIII. Article XVIII implements the federal minimum NFIP standards under 44 CFR 60.3 and is administered by Sussex County's Environmental and Flood Plain Manager (Jeff Shockley, 302-855-7884). Notably, Sussex County does not require mandatory freeboard above the FEMA Base Flood Elevation in unincorporated areas; instead, the ordinance provides an incentive allowing up to 2 feet of additional building height for every foot of voluntary freeboard added above the BFE. Most incorporated municipalities (including Fenwick Island, Bethany Beach, South Bethany, Dewey Beach, Rehoboth Beach, Lewes, and Milford) administer their own flood damage prevention ordinances and have independently joined FEMA's Community Rating System (CRS); Fenwick Island, for example, holds a Class 9 CRS rating that provides a 5% flood insurance premium discount to qualifying policyholders. Coastal development is also subject to DNREC oversight under Delaware's Beach Preservation Act and the Beaches/Dunes regulations administered by DNREC's Division of Climate, Coastal & Energy. The 50% substantial improvement / substantial damage rule of the NFIP (44 CFR 60.3) applies countywide: when the cost of repairs or improvements to a structure within an SFHA reaches half of its market value, the entire structure must be brought into full compliance with current floodplain construction standards. DNREC's Delaware Flood Planning Tool (floodplanning.dnrec.delaware.gov) and FEMA's Map Service Center (msc.fema.gov) are the official sources for parcel-level flood zone determinations.