Kent County, DE Accessory Structures: ADU Rules (2026)

" Section 101-2 defines an ADU as "a self-contained dwelling unit that is secondary to the principal dwelling unit on a property and includes independent living facilities, such as a separate entrance, bathroom, and kitchen," permitted either attached (an "accessory apartment") or detached (a "cottage") on the same lot. Section 101-3 sets the general rules: ADUs are allowed in all residential zones subject to other regulations and building codes; each property is limited to one ADU; manufactured homes cannot be used as ADUs; one dwelling unit on the property must be owner-occupied with a recorded land use restriction; and any ADU with on-site wastewater must secure a Department of Natural Resources and Environmental Control (DNREC) permit before modification.

Section 101-4 adds the development standards: the ADU cannot exceed 50% of the principal dwelling's floor area (accessibility square footage excluded from that cap), a detached ADU must sit on a slab or crawl space with no basement, an attached ADU follows the principal structure's setbacks while a detached ADU must sit behind the principal structure at half its side and rear setbacks, and total lot coverage (impervious cover) across the property is capped at 50%. Applications must include full building plans, a separate floor layout for each finished level, a statement of each room's use, and all entrances and exits. The Board of Adjustment may grant variances from these standards under the procedures in Chapter 205, Zoning.