Sussex County, DE Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Base floor rule
- Lowest floor at/above base flood elevation
- Mandatory freeboard
- None; optional, incentivized
- Height bonus for freeboard
- 1 ft height per 1 ft freeboard, max 2 ft
- Zone AO floor rule
- Depth number or 2 ft above grade, min
- Flood opening size
- 1 sq in per sq ft of enclosed area
- Max fine per violation
- $100 per day, Ch. 115
Summary
Sussex County requires the lowest floor of new and substantially improved residential structures in a special flood hazard area to sit at or above the base flood elevation, with no mandatory freeboard, but it rewards builders who add up to two feet of freeboard with a matching height bonus.
The lowest floor (including basement) shall be elevated to or above the base flood elevation. ... For all structures in special flood hazard areas, height regulations for the districts shown in Articles IV through XX shall apply, with the height measured from the base flood elevation. Provided, however, that in special flood hazard areas the permitted height may be increased by one foot for every one foot of freeboard, not to exceed two feet above the permitted height measured from base flood elevation.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4401089; v17 updated 2025-06-17; through 06-17-2025).
Full Breakdown
5B(1)(a), the lowest floor, including any basement, of a residential structure or the residential portion of a mixed-use structure in Zones A, AE or AO must be elevated to or above the base flood elevation shown on the county's Flood Insurance Rate Map. 5C(2). 5B(1)(b) requires the lowest floor to sit at least as high above the highest adjacent grade as the depth number printed on the flood map, or at least two feet if no depth number is shown. 10 gives builders an incentive: permitted building height in a special flood hazard area is measured from the base flood elevation, and that height may be increased by one foot for every foot of freeboard added, capped at a two-foot bonus. 5B(3)(a)[1]. 5B(2)(c)[2]. 3G(1).
Violations & Fines
A structure lacking the required elevation certificate or other proof of compliance is presumed in violation until documentation is produced, per the definition of violation at Section 115-141.2. Violations of Chapter 115 are misdemeanors under Section 115-229, carrying a fine of up to $100, with each day of continued noncompliance charged as a separate offense against the owner, builder or agent involved.
Frequently Asked Questions
Does Sussex County require freeboard above the base flood elevation?
How high must a new house be built in a Sussex County Zone AO area?
What proof of elevation does Sussex County require before occupancy?
Sources & Official References
Other rules in Sussex County
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