Building an ADU in Raleigh

What you can build here

Raleigh's Unified Development Ordinance (UDO) defines an ADU as "a self-contained dwelling unit that is located on the same lot as a principal dwelling." It may be detached, attached or inside the main home, including above a garage. It must have a lockable outside entrance, and its entrances must be reachable on foot from the driveway, street or alley.

In residential districts, an ADU can go on a lot with an existing detached house or tiny house, or with an attached house, townhouse or tiny house used as two-unit living, or with a townhouse. The city's FAQ lists the districts as R-1, R-2, R-4, R-6, R-10, RX, OX, NX, DX and CX.

You can have one ADU per lot. In a Frequent Transit Area shown in the Comprehensive Plan you can have two, but only one can be attached to the main home, and a townhouse lot is limited to one.

The ADU must sit on a permanent foundation. It can be a manufactured home only if it is 600 square feet or less and meets roof pitch, eave, wall height, siding and skirting rules. ADUs are not allowed on flag lots. Check with your HOA too, since the city says to ask whether ADUs are allowed in your neighborhood. [1][2]

Size, height and setbacks

These are the limits in residential districts under UDO Section 2.6.3. Mixed-use districts follow Section 3.6.2.

Size. The ADU's gross floor area must be less than the main home's. The maximum is 800 square feet on lots under 10,000 square feet and on lots of 10,000 to 40,000 square feet, and 1,000 square feet on lots over 40,000 square feet. Gross floor area includes all conditioned space plus any attached unconditioned space. The city's FAQ says ADUs are "typically between 450-800 square feet."

Detached ADU setbacks:

• Front: at or behind the front wall of the house.
• Side street: 10 feet on lots under 10,000 square feet; 15 feet on larger lots.
• Side and rear lot lines: 5 feet on lots up to 40,000 square feet; 10 feet on larger lots.
• Alley: 4 feet without parking, 20 feet with parking.

Height. Up to 26 feet.

Separation. Unless it is built into another building, an ADU must be at least 6 feet from any other building on the lot. [1][2]

Parking

The city's FAQ says: "No. Additional parking does not have to be provided with an ADU." North Carolina's new ADU law also bars covered cities from setting minimum parking requirements for ADUs from January 15, 2027. [2][4]

What changes with the 2027 state law

Session Law 2026-59 adds G.S. 160D-917, which covers cities of 50,000 or more outside the coastal area. The state demographer estimated Raleigh's population at 504,445 on July 1, 2025. For ADU permit applications filed on or after January 15, 2027, the city must allow at least one ADU with each single-family detached home in residential areas that allow those homes, and must adopt rules by July 1, 2027.

Raleigh's size limits of 800 and 1,000 square feet already fall within the state's range, and the state law lets cities require that an ADU be smaller than the main house. The state law also bars fees higher than for a similar single-family home and says a permitted ADU's parcel can't be subdivided to separate the ADU.

The state law caps the setback a city can require for an ADU at 10 feet, or the zone's general setback if that is less. Raleigh's UDO requires a detached ADU to be 15 feet from a side street on lots of 10,000 square feet or more, and 20 feet from an alley when there is parking.

The UDO currently bars ADUs on flag lots. The state law doesn't list flag lots as an exception. Ask the city how these rules will apply to applications from January 15, 2027. See our North Carolina ADU law page. [1][4][5]

Fees and timeline

Raleigh doesn't list ADU fees on its ADU page. A plan review fee is due before your project is reviewed, and all other permit fees are due when the permits are ready to issue. Use the city's development fee guide and calculator to estimate them.

The city posts standard review turnaround times online. State law requires the first review of residential building plans within 15 business days, with partial fee refunds if it takes more than 20 business days. If your project adds 800 square feet or more of impervious surface, it must also meet the city's lot grading plan requirements.

See our ADU cost guide for budgeting. [3][6][7]

Garage conversions and internal ADUs

Finishing an existing detached garage as an ADU uses the city's ADU Change-of-Use process, as does converting space inside your house. An ADU above a garage is allowed. If your main home is a duplex, only one of the two units may add an internal ADU, and that review is under the North Carolina Commercial Code.

The city's FAQ says all ADUs must meet the fire-resistant separation rules in the North Carolina Residential Building Code. See our garage conversion guide. [1][2][3]

Renting it out and building it yourself

You can't sell an ADU apart from its main home. You can rent it, unless you built it yourself under the owner-builder exemption. In that case, the city says "a statement from the owner that the ADU will be built solely as Not For Rent is required prior to permit issuance."

The city's FAQ gives two different thresholds for needing a licensed general contractor: projects valued over $40,000 in one answer and over $30,000 in another. State law sets the threshold at $40,000 or more. Confirm with the Permit Helpline at 919-996-2500.

Short-term rentals of 30 days or less need a city zoning permit first, and part or all of an accessory structure can be used. Renters can't hold special events in residential districts, and the permit number must appear on all ads. See our guide to hiring ADU help. [1][2][8][9][10]

Permit steps in Raleigh

1. Check your zoning and design rules

   Confirm your zoning district and read UDO Section 2.6.3 (residential districts) or Section 3.6.2 (mixed-use districts). In a historic overlay district, get a Certificate of Appropriateness before construction. [1][2]

2. Pick the right permit path

   A new detached ADU follows the New Single-Family Dwelling process. Finishing an existing detached garage or converting interior space follows the ADU Change-of-Use process, and an attached ADU that adds square footage follows the Accessory Structure and Addition process. See Building an ADU. [3]

3. Choose plans

   You can hire a designer or buy a plan from the city's ADU Fast Track gallery. Fast Track ADUs follow the new single-family dwelling process. [3]

4. Register and gather documents

   Register in the Permit and Development Portal and enter all contractor information. Prepare the Residential Permit Application, a site plan or survey, the Residential Permit Data Form, lien agent details and construction drawings with elevations. Owner-builders also file the Owner Exemption Affidavit. [6]

5. Submit and pay the plan review fee

   Upload all forms and documents as PDFs in the portal. A plan review fee is due before review; check the city's development fee guide. [6]

6. Respond to comments and get your permit

   You'll get email updates and can read review comments in the portal. All other permit fees are due when the permits are ready to issue. [6]

7. Build and pass inspections

   Schedule inspections through the portal as work progresses. [6]

Pre-approved and sample plans

• ADU Fast Track program

  An online gallery of ADU plans pre-reviewed by the city for building code compliance, which you buy from the designer. [3]

Who to call

• Raleigh Permit Helpline

  Questions about ADU permits and the permit portal

  919-996-2500

  [3][10]

Questions people ask