DWELL BEYOND THE ORDINARY
ADU Regulations in Delaware: The Complete Guide
Delaware has always been a state that offers something for everyone. From the quiet farmland of Kent County to the bustling riverfront in Wilmington and the beach towns along the Sussex coast, people are drawn here for its balance of charm, opportunity, and affordability. But like much of the country, Delaware is facing growing pressure on its housing market with climbing home prices and limited rental options. That’s where Accessory Dwelling Units, or ADUs, come into the picture. These modular ADUs may just be the solution to your questions of finding a source of extra income or where to house your elderly family members. ADUs are flexible and perfect
In the guide that follows, we’ll walk through each of Delaware’s counties and key cities to outline exactly what’s allowed, what’s restricted, and where the gaps remain. Whether you’re a homeowner exploring the idea of building a backyard cottage or simply curious about how Delaware is responding to housing challenges, this overview will give you a clear picture of where ADUs fit into the First State’s housing landscape. Psy Homes has been in the non-traditional housing world for decades and we are here to provide you with the answers you need.
Are ADUs Allowed in Delaware?
Yes, but the rules depend entirely on where you live. Delaware does not have a statewide ADU law, which means each city, town, and county creates its own regulations. This ultimately means that information regarding ADUs in individual counties is difficult to access online and the best step is to go straight to your municipality to find out what your building and zoning departments allow.
The type of ADU can also impact what is and is not allowed. Typically, it is slightly easier to get approval for attached ADUs while detached ADUs require more permits and regulations.
What Is Considered An ADU in Delaware?
In Delaware, an Accessory Dwelling Unit is defined as a secondary, smaller residential unit on the same property as a primary home, offering independent living facilities with a kitchen, bathroom, and sleeping area. ADUs are intended to provide independent living space, often for family members or as a source of rental income, and are typically not sold or separated from the main house.
Can Park Model Tiny Homes Be Used As ADUs?
Yes, although it definitely depends on where you live. Park model homes are built to all the standards of an RV home, but with a more permanent foundation. The RVIA standards may make Delaware counties more prone to allowing them as an ADU, but to confirm this, it is important to check with your local zoning authorities. Curious as to what other states have to say about tiny home ADUs? Take a look at the table below.
| AL | IL | MN | NC | TX |
| AZ | IN | MS | ND | UT |
| AR | IA | MO | OH | VT |
| CA | KS | MT | OK | VA |
| CO | KY | NE | OR | WA |
| CT | LA | NV | PA | WV |
| DE | ME | NH | RI | WI |
| FL | MD | NJ | SC | WY |
| GA | MA | NM | SD | |
| ID | MI | NY | TN |
Can Log Cabins Be Used As An ADU?
Yes! If a smaller prefab log cabin fits within the size requirements that your Delaware municipality has for ADUs, it can definitely be a possibility. Especially if you live within a more rural area, you may have a better setup for a log cabin ADU. Local regulations will still control details like setbacks, height restrictions, and whether the ADU must match the exterior style of the primary dwelling, so it’s always best to get your building department’s approval before committing to a purchase.
Can Modern Cabins Be Used As An ADU?
Yes, modern cabins can make a great option for an ADU in Delaware, provided they meet the specific local requirements for things like size, height, and setbacks. In some areas, ADUs can be as large as 1,000 square feet, while other jurisdictions impose stricter limits. Psy Homes has several contemporary cabin models that fall comfortably within these restrictions. As with any ADU, the deciding factor is always local zoning compliance, meaning a cabin design might be fully approved in one town but require adjustments in another.
What is the Difference Between a Prefab ADU & a Modular ADU?
The distinction lies mainly in how they are constructed and delivered. A prefab ADU is built entirely in a factory and shipped as one complete structure, ready to be set on a permanent foundation.
A modular ADU is also factory-built but comes in multiple sections, which are assembled on-site and finalized by a construction crew.
In Delaware, local codes generally treat prefab and modular ADUs the same way as long as they meet building standards and are installed on a permanent foundation. Psy Homes specializes in modular ADUs built to single-wide modular home standards, ensuring they meet both state and local requirements.
What is the Minimum Size for an Accessory Dwelling Unit?
Luckily for you, Delaware doesn’t have a statewide minimum for ADUs, instead leaving it up to the local governments. Most of the time, most counties say a minimum of 200-400 square feet, but to be totally sure, check with your town’s planning and zoning department.
Can My ADU be Bigger Than My House?
No, because ADUs are designed to be an accompanying structure, there are no areas which allow them to be larger than your primary dwelling. Most states cap ADUs at a certain square footage or a percentage of the main house. In Delaware, this is around 800-1,000 square feet.
How Close To My House Can I Build An ADU?
Here again there are no statewide requirements, but the general rule of thumb is a minimum setback of 5 ft and a 3 ft side setback. ADUs are also generally required to be at least 10 ft away from the primary dwelling. While this can offer guidance on your ADU project, double check the numbers with your local zoning department for the best clarity.
Do You Need A Permit For An ADU in Delaware?
You sure do. Every ADU in Delaware requires a building permit, which confirms compliance with zoning, safety, and construction standards. In addition to the building permit, you may also need electrical, plumbing, and HVAC permits, plus environmental health permits if you’re connecting to a septic system. This process might seem like an additional headache
Are There Any Incentives or Grants for ADUs in Delaware?
No, as of right now, Delaware doesn’t have any state-wide programs for ADU grants or financial assistance. With more statewide legislation potentially coming through, it is possible that there may be more federal or state funding available. If affordability is a concern, it’s worth asking your municipality if any temporary initiatives or pilot programs are in place.
Are Psy Homes’s ADUs Built to Code?
Definitely. No ADU leaves Psy Homes without being thoroughly inspected and designed to meet and exceed all local building codes for your area. No matter how you utilize your ADU, you can rest assured knowing all the codes and permits are taken care of.
Can an ADU Have Multiple Bedrooms and Bathrooms?
Don’t limit yourself to one bedroom and bathroom. The counties in Delaware allow enough square footage to choose a multi-bedroom ADU or even two bathrooms if you so wished. You sure can. Psy Homes offers several 1 bedroom ADU models that are perfect for a cozier, minimalist lifestyle. We also design and sell several two bedroom models that may fit the needs of a small family better. Our Grove ADU has the option for two bedrooms and two bathrooms while still fitting under 1,000 square feet!
Are ADUs A Good Investment?
Yes! An accessory dwelling unit offers flexibility in how you use it. You can use it as an additional source of income through short or long-term rentals, house aging parents, or have it as an extra guest house for visiting friends and family. Plus, it can increase your property value when you go to re-sell your house. There are multiple possibilities but the bottom line is ADUs are definitely worth the investment!
What Counties in Delaware Allow ADUs?
Does Kent County Allow ADUs?
It depends. Kent County is the most restrictive of Delaware’s three counties when it comes to accessory dwelling units. As of now, Kent County has no adopted countywide ADU ordinance that expressly permits them on standard single-family lots. Instead, homeowners looking to add a second unit must go through more complex zoning approvals, often requiring special exceptions or variances depending on the property’s zoning designation. This means there’s no by-right path to creating an ADU in Kent County at this time, unlike in Sussex or New Castle.
Interested homeowners need to be prepared for a case-by-case process that may involve public hearings before the Board of Adjustment. Before committing to an ADU project in Kent, you should confirm how your lot is zoned which could give way for an ADU on your property. You can also reach out to the Permits, Building, and Sewer Department for more clarity on the next best step forward.
Does New Castle County Allow ADUs?
Yes! New Castle County has a well-defined ADU program, and in 2024 it became even more flexible. Homeowners in most single-family residential districts can add one ADU per lot, either attached to the main dwelling, within it (like a basement or attic conversion), or detached. Detached ADUs were once limited to very large parcels, but Ordinance 24-087, adopted September 2024, reduced the minimum lot size for detached ADUs from 2 acres down to just 0.5 acres, making them more accessible.
The county also lifted the annual cap on how many ADU permits could be issued. There are, however, conditions: the property owner must live in either the main dwelling or the ADU and only one of the two units can be rented at a time.
Additionally, short-term rentals like Airbnb are restricted. Off-street parking is required for the ADU, and standard setbacks apply to detached units. To keep the process going, reach out to the New Castle Permits and Inspections to find out the next best step.
Does Sussex County Allow ADUs?
It sure does! Sussex County significantly expanded ADU allowances in June 2024 with a new ordinance aimed at addressing housing needs. Under these rules, homeowners can build ADUs as attached or detached units, and the maximum floor area was increased to 1,000 square feet. Importantly, ADUs in Sussex are now allowed to include full kitchens, making them fully independent living spaces, something that was not always permitted before. Like in other counties, only one ADU per lot is allowed, and the homeowner typically must reside in one of the two dwellings.
Sussex still enforces basic land-use rules such as setbacks, height limits, and connection to adequate water/sewer capacity, but the expanded ordinance removed many of the older barriers that limited ADU growth. This means homeowners in Sussex now have one of the clearest and most straightforward paths to legally building a small second home on their property in Delaware. Call the Sussex County Planning and Zoning to start the next steps today!
Accessory Dwelling Unit Requirements by Municipalities
| Delaware City | Zoning Ordinance |
| Wilmington | Zoning |
| Newark | Code of Ordinances |
| Dover | Code of Ordinances |
| Clayton | Zoning Ordinance |
| Milford | Code of Ordinances |
| Smyrna | Code of Ordinances |
Does Delaware City,Delaware, Allow ADUs?
It is not definite one way or the other. Delaware City does not have a clear ordinance that explicitly addresses accessory dwelling units. Its zoning code covers standard residential uses and accessory structures, but ADUs as separate living spaces are not specifically outlined. This likely means they are not permitted by right and may require a variance or special review if proposed. Homeowners interested in building an ADU here should contact the Delaware City Planning and Zoning Department directly to confirm what may be possible under current zoning classifications and to see whether any updates are being considered.
Does Wilmington,Delaware, Allow ADUs?
It appears that way! Wilmington has been actively updating its approach to ADUs. The city is moving toward allowing them broadly on single-family lots, with recent amendments expanding the maximum allowed size to roughly 1,200 square feet and reducing barriers like lot coverage ratios. Detached and attached ADUs are both being considered within these reforms, though design and setback rules still apply. Because Wilmington’s zoning is undergoing changes, homeowners should review the most current zoning amendments through the city’s Planning and Development Department or City Council updates to confirm whether their property is eligible for a by-right ADU or if conditional approvals are still required.
Does Newark,Delaware, Allow ADUs?
Newark’s zoning code references accessory uses in residential districts, but it does not clearly define ADUs as a by-right option across the city. While there has been discussion in planning documents about using ADUs to expand affordable housing, no specific ordinance has been formally adopted citywide to establish uniform ADU standards. Homeowners considering an ADU in Newark should check their property’s zoning district and confirm with the Planning and Development Department whether an accessory apartment or dwelling is permitted as a special exception or conditional use. Staying tuned to upcoming housing reform proposals is important here, as Newark is actively reviewing zoning changes.
Does Dover,Delaware, Allow ADUs?
Yes! Dover does allow ADUs but regulates them closely. The city has a set of rules capping the size of an ADU at 900 square feet and requiring that the ADU use the same driveway opening and curb cut as the primary residence. ADUs must also comply with building code and utility requirements, particularly septic and water capacity if not connected to city services. Only one ADU is permitted per lot, and additional parking spaces may be restricted. Homeowners should start with Dover’s Planning Department to obtain the accessory dwelling guidelines and confirm the application process, as permits and inspections are required before occupancy is granted.
Does Clayton,Delaware, Allow ADUs?
Possibly, but it is not definite. Clayton does not have a published ordinance that explicitly allows or regulates ADUs. Its zoning code includes provisions for accessory uses, but no formal ADU standards appear in the city’s regulations. This suggests that ADUs are not permitted by right and may only be considered on a case-by-case basis, if at all. Anyone in Clayton interested in building an ADU should contact the Town of Clayton Planning and Zoning Department to review their specific lot and zoning designation. City officials can clarify whether an ADU could be permitted under current rules, or whether a variance or rezoning would be necessary.
Does Milford,Delaware, Allow ADUs?
Yes! Milford has one of the clearer ADU frameworks in Delaware, though it requires a more involved approval process. ADUs are allowed in residential zones (R-1, R-2, R-3, and R-8) but only through a conditional use permit, which involves public hearings before both the Planning Commission and City Council. The application fee is $700, and homeowners must designate the primary residence or the ADU as their owner-occupied dwelling, with the requirement recorded officially. Milford defines two types of ADUs: accessory cottages (detached units like garage conversions) and accessory apartments (units within the main home). Anyone pursuing an ADU in Milford should carefully review the city’s published ADU guidelines and be prepared for the conditional use review process.
Does Smyrna,Delaware, Allow ADUs?
Like some of the other Delaware municipalities, it is unclear since Smyrna does not appear to have a specific ADU ordinance in place at this time. The zoning code outlines accessory structures and uses but does not explicitly define accessory dwelling units as a separate category. This likely means ADUs are not permitted by right, and approval would require additional review, possibly through a variance or conditional use depending on the zoning district. Interested homeowners in Smyrna should contact the town’s Planning and Zoning Department to confirm whether their property is eligible for an ADU and to see if any policy changes are under consideration.
Searching for an ADU Builder Serving Delaware?
If you found out ADUs are allowed in your Delaware county, it’s time to take the next step and find a trustworthy ADU builder you can partner with. Psy Homes is pleased to offer you all experience and skills to make your dream ADU become a reality. Simply contact us and talk to a sales representative or request a free quote to move the process ahead.
We know that these days, it can be hard to choose who to work with to make your dreams become a reality. That’s why we promise transparent pricing, a commitment to the end, and an excellent work ethic. Choose Psy Homes today and watch your vision of the ideal ADU unfold from start to finish.