Carteret County, NC Accessory Structures: ADU Rules (2026)

Section 1102 of the Carteret County Zoning Ordinance defines an accessory building or structure as a detached subordinate building whose use is incidental and secondary to the principal building or use on the same lot, and then flatly bars residential use of it: 'Under no circumstances shall an accessory building or structure be used for residential occupancy.' That means a detached garage, workshop, or storage building on a residential lot in unincorporated Carteret County cannot legally serve as a rental unit, guest cottage, or anyone's dwelling, regardless of the zoning district.

The ordinance does allow a different, narrower form of secondary living space: the 'efficiency unit,' defined in the same section as an additional dwelling unit inside a single-family dwelling, not a separate structure, which is permitted in all residential zones if it contains no more than 25 percent of the home's gross heated and cooled floor area and the lot meets the minimum lot size requirement for its zoning district under Section 3101. Because the efficiency unit must be built into the principal house rather than a standalone accessory building, it does not create an exception to the accessory-structure occupancy ban; a homeowner who wants a legal second living space has to add it inside the primary dwelling and meet the 25 percent floor-area and lot-size tests, not convert a detached garage or shed.