Chapel Hill, NC Accessory Structures: ADU Rules (2026)

Chapel Hill's LUMO defines an accessory apartment as 'a unit with space for cooking, sleeping, and bathroom facilities that may be attached to, within, or detached from the primary house' (Appendix A). The use is described in the LUMO Use Matrix as 'Dwelling units, single-family with accessory apartment' and is permitted by-right in most residential zoning districts. For each single-family dwelling, only ONE accessory apartment OR cottage is permitted on the lot. The January 21, 2026 LUMO amendments package ('Housing Choices for a Complete Community') made three major changes: (1) increased the maximum size of an accessory dwelling unit from 75 percent of the primary residence's unit size to a flat 1,000 sq ft (substantially expanding small-lot ADU potential); (2) increased the maximum cottage unit size from 1,200 sq ft to 1,500 sq ft; (3) eliminated minimum parking requirements (which previously required dedicated off-street parking for accessory apartments); (4) added flexibility allowing an accessory dwelling unit on its own lot, sellable separately from the principal dwelling, in eligible districts; (5) increased maximum duplex floor area from 3,000 sq ft to 5,000 sq ft. Detached ADUs must be located in the established rear yard and meet the primary residence's side and rear setback requirements for the underlying zoning district (e.g., 14 ft from any property line in R-1; lower in R-3/R-4/R-5/R-6). Construction requires a building permit through Chapel Hill Building and Development Services under the 2018 NC Residential Code with Orange County 115 mph basic wind speed. North Carolina has no statewide ADU enabling statute or preemption — HB 409 (Regulation of Accessory Dwelling Units) passed the House in April 2023 but died in the Senate Rules Committee without becoming law, leaving local control intact. Chapel Hill is among the most permissive NC towns post-2026 amendments.