If you have ever toured a home in Carolina Place or Forest Hills and spotted a carriage house out back, you have already seen one of Wilmington’s oldest housing ideas making a comeback. Accessory dwelling units, or ADUs, are small second homes on the same lot as a single-family house. In the city of Wilmington, the rules around them loosened when the Land Development Code was updated, and that has real consequences for buyers who want space for aging parents, sellers marketing a lot with potential, and investors weighing rental income.
Here is what the current rules say, where they come from, and what to check before you buy, build, or list.
What counts as an ADU in Wilmington
The city’s Land Development Code, Section 18-200, as amended in the city’s spring 2024 maintenance amendments, recognizes two basic types:
- Detached ADUs stand on their own. Think detached garage apartments, backyard cottages, and converted outbuildings.
- Attached ADUs share a roof and at least one wall with the main house, or are internal units carved out of the main house with their own separate exterior entrance.
An ADU can be new construction, a conversion of an existing building, or an addition. As WilmingtonBiz noted in its June 2024 look at local ADUs, a true ADU has its own full kitchen and bathroom, which is what separates it from a bonus room or guest suite.
The key rules, in plain English
One per lot, and only with a single-family home
The code allows ADUs only as an accessory to a principal single dwelling, and only one ADU per lot. If the main structure is a duplex or a multifamily building, the ADU rules don’t apply the same way.
Size caps
An ADU can be no larger than 50 percent of the main home’s gross floor area or 1,200 square feet, whichever is less. So a 1,600-square-foot house could support an ADU of up to about 800 square feet. WilmingtonBiz reported that the earlier limit was 900 square feet, and the city’s zoning administrator noted that an ADU also can’t be taller than the main house.
Setbacks and lot size
Detached ADUs follow the city’s accessory structure setback table, which puts them at least 5 feet from side and rear lot lines. Attached ADUs are treated like part of the main building and have to meet that zoning district’s principal-building setbacks. A detached ADU also needs a lot that meets the district’s minimum lot area. A city cleanup amendment (case LDC-3-522) restored the option for internal ADUs on legal nonconforming lots, which matters in older neighborhoods where many lots are smaller than today’s minimums.
Permits go through New Hanover County
Zoning is the city’s call, but building permits and plan review run through New Hanover County, even inside city limits, as WHQR explained in its 2024 how-to guide. Water and sewer connections through CFPUA are their own step. Outside city limits, in unincorporated New Hanover County or the beach towns, different ordinances apply, so always confirm which jurisdiction a property is in.
What this means for buyers
A home with an existing ADU, or a lot that can legally support one, gives you options: a place for a parent, a college student, a home office, or a long-term tenant. Before you write an offer, use your due diligence period to check a few things:
- Was it permitted? Ask for permit records for any garage apartment or cottage. An unpermitted unit can be a problem for insurance, appraisal, and future resale.
- Does it fit current rules? Older units may be legal nonconforming. That is usually fine, but expansions or rebuilds may have to meet today’s code.
- Utilities and flood zone. Confirm water and sewer service and check the flood zone for both structures. Insurance for a second dwelling on the lot is worth quoting early.
- HOA covenants. City zoning may allow an ADU while neighborhood restrictive covenants prohibit it. Read the recorded covenants before you count on building one.
What this means for sellers
If your home already has a permitted ADU, lead with it. Floor plans, permit history, and utility details for the second unit help buyers and appraisers understand what they are looking at. If you don’t have one but your lot clearly meets the size and setback standards, it is fair to mention the potential, but avoid promising a buyer that something can be built. Let them confirm with the city.
What this means for investors
ADUs can add long-term rental income, and WilmingtonBiz’s reporting found local owners renting carriage houses to travel nurses on multi-month stays. If you are thinking about short-term rentals instead, Wilmington has separate whole-house lodging rules and registration requirements, so treat the ADU rules and short-term rental rules as two different questions. Run the numbers on construction costs, which can be substantial, and check how a lender will treat projected rent before you buy a property for its ADU potential.
FAQ
Can I build an ADU on any lot in Wilmington?
Not any lot, but many. You need a principal single-family home, only one ADU is allowed, and a detached unit needs a lot that meets the district’s minimum area. The city’s zoning administrator told WilmingtonBiz that almost all of the city’s roughly 30,000 residential lots could potentially host one.
How big can a Wilmington ADU be?
Up to 50 percent of the main home’s gross floor area or 1,200 square feet, whichever is smaller, and no taller than the main house.
Does an ADU add value to a home?
It often adds appeal and flexibility, but value depends on the unit’s quality, permits, and comparable sales. A local appraiser and recent comparable sales are the best guide.
Do the same rules apply in Wrightsville Beach or Carolina Beach?
No. Beach towns and unincorporated New Hanover County have their own zoning, so check the specific town’s ordinance.
Thinking about a home with room for family or income?
Whether you want a Wilmington home with a carriage house, a lot with room to grow, or help marketing an ADU property you already own, we know these neighborhoods street by street. Talk with Aspyre Collective about your plans and we’ll help you sort out what is possible before you commit.
