Apex, NC Accessory Structures: ADU Rules (2026)

Apex UDO Sec. 4.5.6 (effective February 27, 2024) defines an Accessory Apartment as a secondary dwelling unit either (1) in or added to an existing single-family dwelling, (2) in an accessory structure on the same lot as the principal single-family dwelling, or (3) on all but the ground floor of a commercial use in B1 Neighborhood Business, B2 Downtown Business, MEC-CZ Major Employment Center, TND-CZ Traditional Neighborhood, PUD-CZ Planned Unit Development, MORR Mixed Office-Residential-Retail, or SD-CZ Sustainable Development Districts. The unit must be a complete, independent living facility with kitchen, sanitation, and sleeping provisions. Standards: (A) Number — maximum 1 accessory apartment per principal single-family dwelling; (B) Attached size — no limit; (C) Detached size — outside the Small Town Character Overlay District (STCOD), no larger than 40 percent of the principal dwelling's heated square footage; inside the STCOD, no larger than 50 percent of the principal heated square footage OR 1,000 heated square feet, whichever is smaller; (D) Similar Materials — must be substantially equivalent to the principal dwelling; (E) Compatible Character — must be compatible and subordinate in size; (F) Yard Setbacks — attached units comply with the underlying district's minimum yard setbacks; detached units comply with UDO Sec. 5.2.7 dimensional standards for detached accessory structures (5 ft side/rear minimum); (G) Ownership — in residential districts the accessory apartment must remain under the same ownership as the principal single-family dwelling (no separate sale); in B1, B2, MEC-CZ, PUD-CZ, SD-CZ, MORR, and TND-CZ districts, accessory units may be under separate ownership (effectively allowing condo-style sale). UDO Sec. 5.2.7.E specifically lists Accessory Apartments in the encroachment table — minimum 5 ft from side or rear property line for detached units. UDO Sec. 5.2.2.B.4 lists Accessory Apartments as 'None' for encroachments into the front setback (they must meet the full district front setback). Front-yard placement is generally prohibited; under Sec. 5.2.7.B.2, an accessory structure may only be in the front yard if at least 60 ft from the front property line. 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.