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Building an ADU in Wilmington, North Carolina

City code and North Carolina law · Last reviewed October 10, 2026

Wilmington allows one accessory dwelling unit (ADU) on a lot with a single-family home in its R-15 through R-3, MD-10, MD-17, RO and historic (HD, HDR, HDMU) zoning districts. Under Land Development Code Section 18-200, an ADU can be no larger than 50% of the main house or 1,200 square feet, whichever is less. A detached ADU needs 5-foot side and rear setbacks and can't be taller than the house or sit in front of it. North Carolina's 2026 ADU law does not apply here, because New Hanover County is in the state's coastal area. [1][2][3]

Wilmington at a glance

Zoning districts
R-15, R-10, R-7, R-5, R-3, MD-10, MD-17, RO, HDR, HDMU and HD Permitted with conditions [1]
How many
One ADU per lot, only with a single-family home No more than two accessory buildings in total [1]
Max size
50% of the main house's gross floor area or 1,200 sq ft, whichever is less [1]
Types
Detached (garage apartment, backyard cottage), attached, or internal with its own outside entrance [1]
Detached ADU setbacks
5 ft side and rear Not in front of the house or closer to a side street than the house [1]
Attached ADU setbacks
Same as the main house in that zoning district [1]
Height
No taller than the main house [1]
Utility meters
The code defines an ADU as having no utility meter of its own [5]
Selling
Can't be on its own lot [5]
2026 state ADU law (G.S. 160D-917)
Does not apply: Wilmington (126,247 people in 2025) is over 50,000 but in coastal New Hanover County [2][3][7][8]
Building permits
Issued by New Hanover County through its COAST portal [6]
On this page
  1. At a glance
  2. What you can build here
  3. Size, height and setbacks
  4. Parking
  5. Does the 2026 state ADU law apply in Wilmington?
  6. Permits and inspections
  7. Garage conversions and internal units
  8. Renting and selling
  9. Permit steps
  10. Who to call
  11. Questions people ask

What you can build here

Wilmington's ADU rules are in Land Development Code (LDC) Section 18-200. The code defines an ADU as "a residential unit located on the same lot as a single dwelling unit, either internal or attached to the principal dwelling unit or in a detached structure," with its own kitchen, sleeping area, closet space and bathroom.

ADUs are "permitted with conditions" in these zoning districts: R-15, R-10, R-7, R-5, R-3, MD-10, MD-17, RO, HDR, HDMU and HD. The LDC's accessory use table leaves them out of MH, UMX, CBD and the commercial, office and industrial districts. Check your zoning on the city's zoning maps.

One ADU, with a single-family home only. Section 18-200 says "ADUs shall only be allowed when constructed as an accessory to a principal single dwelling" and "only one ADU shall be permitted on any lot." A lot can have at most two accessory buildings (pools don't count), and only one of them can be an ADU. In cluster developments, the code says ADUs aren't counted toward density.

You can create an ADU by new construction, by converting an existing building, or as an addition. Types include:

[1][4][5]

Size, height and setbacks

Historic districts. In separate-use historic districts, setbacks and distances from other buildings are reviewed through the certificate of appropriateness process. Ask the Zoning team about historic district review before you design. [1][6]

Parking

The LDC's parking table (Table 18-341.1) has no separate line for ADUs. Section 18-341 applies minimum parking to homes outside the city's 1945 Corporate Limits, and the table sets "No minimum" for detached dwelling units there. Beyond that, the section says "there shall be no minimum parking requirements" except for some nonresidential uses.

How this applies to an ADU on your lot is a question for the Zoning team at 910.254.0900 or zoning@wilmingtonnc.gov. [4][6]

Does the 2026 state ADU law apply in Wilmington?

No. Session Law 2026-59 (Senate Bill 445), signed August 11, 2026, added G.S. 160D-917. Starting with ADU permit applications filed on or after January 15, 2027, it requires covered cities to allow at least one ADU with each single-family detached home, with no minimum parking and a maximum size set between 800 and 1,000 sq ft. But subsection (h) says it "applies only to cities with a population of 50,000 or greater, that are not in the coastal area, as that term is defined in G.S. 113A-103."

Wilmington passes the population test: the state demographer estimated 126,247 residents on July 1, 2025. It fails the location test. Wilmington is a municipality of New Hanover County, and G.S. 113A-103 names New Hanover among the counties designated as coastal-area counties as of July 1, 2012. So G.S. 160D-917 does not apply, and the city's own LDC decides ADU rules here. The law also says nothing in it stops a local government from allowing ADUs where it isn't required.

See our North Carolina page for the statewide rules, and compare Raleigh, Charlotte and Asheville, which the law does cover. [2][3][7][8]

Permits and inspections

A building permit is required for accessory structures and new construction within the city limits. The city says to confirm your project meets the Land Development Code first, with the Zoning team at the Skyline Center, 929 N. Front St.

New Hanover County's Permits & Inspections department issues the building permits. You apply, pay fees and schedule inspections through the county's COAST permitting portal. Contact COAST at 910.798.7308 or coast@nhcgov.com. The county's Building Safety page covers whether you need a permit and what it costs.

In a historic district, you may also need a certificate of appropriateness (minor or major works) from the city. See our ADU permit process guide. [1][6][8]

Garage conversions and internal units

The LDC lets you create an ADU by converting an existing building, such as a detached garage, or by adding on to one; detached garage apartments are one of the listed types. The converted building must still meet the ADU size cap and the accessory building setbacks and height limit. An internal ADU, carved out of the house, needs its own outside entrance. See our garage conversion guide. [1]

Renting and selling

The LDC's ADU section doesn't address long-term rental of an ADU. Short-term lodging is regulated separately: for example, bed and breakfast guest rooms "shall not be in any accessory building." Ask the Zoning team before you list an ADU for short stays.

The code's definition says an ADU "cannot be situated on its own lot," so it can't be split off and sold separately. It also says an ADU is "without its own utility meter(s)," so ask the Zoning team how that applies to your utility service. [1][5]

Permit steps in Wilmington

  1. Check your zoning district

    Find your district on the city's zoning maps and confirm ADUs are allowed there (Table 18-198). [1][6]

  2. Confirm the LDC rules with Zoning

    Check size, setbacks, height and the two-accessory-building limit with the city's Zoning team at 910.254.0900 or zoning@wilmingtonnc.gov. [1][6]

  3. Historic district review (if it applies)

    In a historic district, get a certificate of appropriateness; setbacks and building spacing are reviewed through that process. [1][6]

  4. Apply for the building permit

    Apply and pay through New Hanover County's COAST portal. Questions: 910.798.7308 or coast@nhcgov.com. [6][8]

  5. Build and pass inspections

    Schedule inspections through COAST as work progresses. [8]

Who to call

Questions people ask

Are ADUs allowed in Wilmington, NC?

Yes, one per lot with a single-family home in the R-15, R-10, R-7, R-5, R-3, MD-10, MD-17, RO, HDR, HDMU and HD districts, under Land Development Code Section 18-200. [1]

How big can an ADU be in Wilmington?

No more than 50% of the main house's gross floor area or 1,200 square feet, whichever is less. [1]

Does North Carolina's 2026 ADU law apply to Wilmington?

No. G.S. 160D-917 covers only cities of 50,000 or more that are not in the coastal area. Wilmington has about 126,000 people, but it is in New Hanover County, one of the coastal-area counties listed in G.S. 113A-103, so the city's own code still controls. [2][3][7][8]

What are the setbacks for a detached ADU in Wilmington?

5 feet from side and rear lot lines. It can't be in front of the main house or closer to a side street than the house, and it can't be taller than the house. [1]

Who issues ADU building permits in Wilmington?

New Hanover County Permits & Inspections, through its COAST portal. Check zoning with the city first at 910.254.0900 or zoning@wilmingtonnc.gov. [6]

Sources (8)
  1. Wilmington Land Development Code, Article 3, Use Standards: Sections 18-198 to 18-200 (Supp. No. 9), City of Wilmington (Municode). Accessed October 10, 2026.
  2. Session Law 2026-59 (Senate Bill 445), Regulatory Reform Act of 2026, North Carolina General Assembly. Accessed October 10, 2026.
  3. G.S. 113A-103, Definitions (Coastal Area Management Act), North Carolina General Assembly. Accessed October 10, 2026.
  4. Wilmington Land Development Code, Article 5, Site Development Requirements: Sections 18-341 and 18-421 (Supp. No. 9), City of Wilmington (Municode). Accessed October 10, 2026.
  5. Wilmington Land Development Code, Article 8, Measurements and Definitions: Dwelling unit, accessory, City of Wilmington (Municode). Accessed October 10, 2026.
  6. Build structure or addition, City of Wilmington. Accessed October 10, 2026.
  7. Aspects of Municipal Population Change (Vintage 2025 estimates), North Carolina Office of State Budget and Management. Accessed October 10, 2026.
  8. Permits & Inspections, New Hanover County. Accessed October 10, 2026.

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