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

Wake County's ADU rules come from the Wake County Unified Development Ordinance (UDO) — codified in the County Code of Ordinances and administered by Wake County Planning, Development & Inspections (Inspections & Permits) — and from the published ADU program on the wake.gov website. The County's published ADU page defines an ADU as "a secondary dwelling unit that is subordinate to the primary dwelling," and explicitly recognizes two categories: (1) Detached ADUs — a living unit physically separated from the main house and its attached garage, not sharing a common wall or other conditioned space; this includes a new detached structure built to create an independent living unit, conversion of an existing detached accessory structure (garage, workshop, office, art studio) into a dwelling, and a separate living space built above or adjacent to an existing detached garage; and (2) Attached/Internal ADUs — a separate living unit that is within or attached to the existing or proposed primary dwelling or its attached garage, sharing a wall or other conditioned space; this includes converting an existing non-living space such as a storage area, attached garage, attic, or crawl space into a living unit. An ADU must be "a complete, independent living facility" with its own kitchen, sanitation, and sleeping provisions.

The Wake County ADU FAQs (wake.gov) confirm three important points that distinguish Wake County from many other North Carolina jurisdictions: (a) ADUs are allowed on lots zoned to permit single-family or multifamily residential uses, subject to compliance with the applicable development standards in the UDO; (b) there is NO owner-occupancy requirement — "homeowners are not required to live on the property" where the ADU is built; and (c) the County's ADU program runs through the standard Wake County Permit Portal — applicants apply for building, electrical, plumbing, and mechanical permits, and address assignment for the ADU is initiated after a building permit application has been filed.

Because Wake County does not operate a public sewer utility in most unincorporated areas, the septic interaction is significant. The wake.gov FAQ explicitly notes: "If a property is served by a septic system (an onsite wastewater system), an Accessory Dwelling Unit may alter the wastewater design flow of the septic system, resulting in the need for additional wastewater permits." That review is done by Wake County Environmental Services — Onsite Water Protection. An ADU added to a 3-bedroom septic system, for example, may push the design flow above the system's capacity and require either a system upgrade or a smaller ADU.

ADUs must comply with all other applicable UDO development standards (zoning-district setbacks, height limits, maximum lot coverage, accessory-structure rules) and with the NC State Building Code (NC Residential Code for ADUs accessory to one- or two-family dwellings, with full kitchen, bathroom, and required egress). Standard NC fire and life-safety provisions apply (smoke and CO alarms, egress windows in sleeping rooms, minimum ceiling height, plumbing and electrical code).

An important jurisdictional note: every incorporated city and town within Wake County — Raleigh, Cary, Apex, Wake Forest, Garner, Holly Springs, Fuquay-Varina, Knightdale, Morrisville, Rolesville, Wendell, and Zebulon — operates under its own zoning ordinance and has its own ADU rules. The City of Raleigh's ADU rules (Raleigh Unified Development Ordinance) differ from the County's and from each other municipality's. Property owners should first confirm jurisdiction using the Wake County iMAPS GIS tool, then apply under the correct authority. Contact the Wake County "ADU Ally" team at (919) 856-6335 before starting an ADU project in unincorporated Wake County.