Sussex County, DE Environmental Rules: Boat Dock Permits (2026)

Section 115-186(A) sets specific dimensional limits for accessory boathouses and boat slips in residential districts. A boathouse cannot be used as a dwelling, guest house or servants' quarters unless another chapter section specifically allows it. Its height is capped at 25 feet above mean high water, and it cannot exceed 25 feet in width or 50 feet in depth. A boathouse also cannot be built beyond the established bulkhead line, nor closer than 10 feet to a side lot line, and boathouses and boat slips together with other accessory buildings may occupy no more than 35% of a required rear yard.

Section 115-186(B) separately governs docks, piers and wharves, whether accessory to a residence or not, in any zoning district. Projection of these structures into waterways beyond the waterway line, lot lines or established bulkhead lines, and the placing of mooring piles or buoys, is limited by county ordinances, state law and U.S. Army Corps of Engineers regulations, and in no case may a dock, wharf, pier or pile project more than 10% of the width of the waterway. Groins, levees, bulkheads, piling, breakwaters and similar structures must be built and maintained to the location and construction standards of the county, the state and the Army Corps of Engineers, meaning a Sussex County zoning permit alone does not clear a dock project; state DNREC subaqueous lands and wetlands permitting, plus federal Corps review, still apply on top of the local 10% rule.

These standards sit within Article XXV's Supplementary Regulations, applying county-wide in addition to the district-specific yard and setback tables elsewhere in Chapter 115.