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Building an ADU in Annapolis

City code and Maryland law · Last reviewed October 10, 2026

The City of Annapolis has allowed accessory dwelling units (ADUs) since October 2021. You can have one ADU per lot, inside your house, as an addition, in a converted garage or as a new backyard building. ADUs are permitted in most residential zones and need a special exception in a few others. A new ADU outside the house's existing footprint can be up to 850 sq ft, the owner must live on the property, no extra parking is required, and you need a rental license if you rent it out. [1][2][3]

Annapolis at a glance

Where ADUs are allowed
Permitted in R1A, R1B, R1, R2, R3, R3-R, R4 and R4-R Special exception in R2-NC, R3-NC, R3-NC2, C1 and C1A [2][5]
Number allowed
One ADU per lot, with its own separate entrance [1]
Types
Inside the house, attached addition, garage conversion, or new detached building [1][2]
Max size
850 sq ft of livable space, unless built within the existing footprint of the house [1][2]
Owner occupancy
Required: the owner must live in the house or the ADU, under common ownership [1][2]
Parking
No additional parking required [2]
Impervious surface
No added paving or roof area unless stormwater is treated or the same coverage is removed elsewhere [1]
Special exception fee
$1,200 (only in districts that require one) [6]
Rental license
Required for any rented ADU $125 standard license, $650 or $750 short-term [1][2][6]
Short-term rental
License required New licenses paused under a 12-month moratorium adopted March 9, 2026, except for owner-occupied units; non-owner-occupied licenses capped at 10% per blockface [2][11][14]
Selling separately
No; you can only sell the ADU with the house [13]
On this page
  1. At a glance
  2. What you can build
  3. Which zones allow ADUs
  4. Size, height and placement
  5. Parking, utilities and environmental rules
  6. Renting it out and short-term rentals
  7. Fixing an unpermitted ADU
  8. Maryland's 2025 ADU law and Annapolis
  9. Permit steps
  10. Who to call
  11. Questions people ask

What you can build

Annapolis defines an ADU as "an accessory building, or portion of a building, designed or used exclusively for residential occupancy that is located in a single family dwelling or on the same lot." The city says an ADU can be added inside an existing single-family home, as an addition, by converting an attached or detached garage, or as a new building on your lot. Each ADU has its own kitchen, bathroom, living area and entrance.

The rules are in City Code Section 21.64.010, adopted by Ordinance O-9-21 in October 2021:

These are the City of Annapolis's rules. Check your zoning on the city's zoning map. For Maryland's statewide ADU law, see our Maryland page. [1][2][3][4]

Which zones allow ADUs

ADUs are a "use subject to standards" in the city's residential Table of Uses. They are permitted in the R1A, R1B, R1, R2, R3, R3-R, R4 and R4-R districts. In the R2-NC, R3-NC, R3-NC2, C1 and C1A districts, they need a special exception.

A special exception is decided by the Board of Appeals, and you must get it before you apply for a building permit. The application fee is $1,200. Properties in an overlay district or a historic district may face more standards, and work in a historic district needs Historic Preservation Commission approval before the building permit. [2][3][5][6]

Size, height and placement

Size. The city code says the maximum size of any ADU "that is not established within the existing footprint of the principal structure is eight hundred fifty square feet of livable space." An ADU inside the existing house, such as in a basement, isn't held to that cap.

State law. Maryland's ADU law defines an ADU as "not greater than 75% of the size of" the main house, and the Maryland Department of Planning says local governments "may not limit the size of ADUs to anything below the 75% limit." For a house larger than about 1,133 sq ft, 75% of its size is more than 850 sq ft. If your plans go above 850 sq ft, confirm with the Department of Planning and Zoning which limit applies to your project.

Height and setbacks. A detached ADU follows the bulk regulations for buildings accessory to single-family homes in your zoning district, which set its setbacks from the street and neighbors. Citywide, a detached accessory building can't be taller than the main building, must be at least 3 ft from any other building, and can't cover more than half of a required yard. An attached ADU must meet the main house's yard requirements.

Paving and roof area. You can't add impervious surface to a lot with an ADU unless the department finds it will be treated or managed, or you remove the same amount elsewhere on the property. [1][2][3][4][7][8][9]

Parking, utilities and environmental rules

Parking. The city's ADU FAQ answers "Is additional parking required?" with "No."

Water and sewer. The city's ADU guide lists a separate water and sewer connection among the things to plan for. Under the FY 2027 fee schedule, the capital facility charge is $1,700 for sewer and $3,200 for water per equivalent dwelling unit, and the city code counts "an individual residential dwelling unit" as one equivalent dwelling unit. Ask the Department of Planning and Zoning what your project will owe.

Stormwater and trees. If the ADU adds impervious surface, the city calculates stormwater treatment and you must carry out a mitigation strategy. Other requirements may apply depending on the area disturbed and any trees or plants removed. Projects in the city's Critical Area overlay face more standards. [2][3][6][10]

Renting it out and short-term rentals

A rental license is required for any rented ADU, along with an inspection by the Department of Planning and Zoning. The city says "Rentals may be short- or long-term." Under the FY 2027 fee schedule, a standard rental operating license is $125, and a short-term rental license is $650 for an owner-occupied property or $750 for a non-owner-occupied one.

For a short-term rental, you must get a short-term rental license before listing on a hosting platform. The city caps non-owner-occupied short-term rental licenses at 10% of the residential units on a blockface (one license on blockfaces with fewer than ten units). Owner-occupied short-term rentals are exempt from the caps. Apply through the city's Short Term Rental Portal, and confirm with Planning and Zoning how the rules apply to your ADU.

Moratorium. On March 9, 2026, the City Council adopted Ordinance O-40-25, a 12-month moratorium on new short-term rental licenses that took effect when passed. Renewals of existing licenses held in full compliance can continue. The moratorium doesn't apply to owner-occupied units, where the record owner lives primarily at the licensed property (more than half the year) and provides proof of ownership and residency. Ask Planning and Zoning whether an ADU on the lot where you live qualifies, and whether the moratorium is still in effect.

You can't sell the ADU on its own. The city says "You can only sell the ADU if you sell your house too." [1][2][6][11][12][13][14]

Fixing an unpermitted ADU

The city says you can legalize an unpermitted ADU that is already on your lot, and to contact the Department of Planning and Zoning for details at 410-260-2200. [3][13]

Maryland's 2025 ADU law and Annapolis

Maryland's HB 1466 says "On or before October 1, 2026, each legislative body shall adopt a local law authorizing the development of accessory dwelling units." The Maryland Department of Planning says a jurisdiction whose existing ADU law already meets all of HB 1466's requirements doesn't need to change it.

The Maryland Department of Planning says HB 1466 doesn't require by-right approval; a local government may use a process that requires a conditional use or special exception. State law does say a local ADU law may not set side and rear setbacks stricter than the existing setbacks for accessory structures, and may add off-street parking requirements only after a parking study and with a waiver process. Annapolis doesn't require extra parking for ADUs. In the city code as posted on Municode (version of September 28, 2026), Annapolis's ADU section still lists only its 2021 ordinance, O-9-21, in its history. Ask the Department of Planning and Zoning whether any changes are pending. [1][2][8][15]

Permit steps in Annapolis

  1. Collect information

    Find your zoning district on the city's zoning map, check whether you need a special exception, and read the ADU standards and your district's bulk rules. Get a survey by a licensed surveyor. [3]

  2. Meet with Planning and Zoning (optional)

    Call 410-260-2200 to schedule a pre-application meeting to review your preliminary design, the special exception process and permit review. [3]

  3. Design the ADU and site plan

    Use a licensed architect or purchased plans. A licensed civil engineer or landscape architect prepares a site plan showing the ADU, property lines, existing structures and trees, topography, utilities and any stormwater features. [3]

  4. Get a special exception or historic approval if needed

    Apply to the Board of Appeals for a special exception, or to the Historic Preservation Commission for historic district approval, before you submit the building permit. [3]

  5. Apply for the building permit

    Submit a building permit application to the Department of Planning and Zoning through the city's online permit portal, including any special exception or historic approval. [3]

  6. Build, inspect and get a certificate of occupancy

    Schedule building inspections with the Department of Planning and Zoning, then receive a Certificate of Occupancy. If you will rent the ADU, apply for a rental license. [1][3]

Who to call

Questions people ask

Are ADUs allowed in Annapolis?

Yes. They are permitted in the R1A, R1B, R1, R2, R3, R3-R, R4 and R4-R districts, and allowed by special exception in R2-NC, R3-NC, R3-NC2, C1 and C1A. Only one ADU is allowed per lot. [1][2]

How big can an ADU be in Annapolis?

The city code caps an ADU outside the house's existing footprint at 850 sq ft of livable space. State law defines an ADU as up to 75% of the house, and the state planning department says local limits can't go below that, so confirm with Planning and Zoning if you want something larger. [1][7][8]

Do I have to live on the property?

Yes. The owner must live in either the main house or the ADU, and both must be under common ownership. [1][2]

Do I need parking for an ADU in Annapolis?

No. The city says no additional parking is required. [2]

Can I rent my Annapolis ADU on Airbnb?

You need a rental license for any rented ADU, and the city says rentals may be short- or long-term. A short-term rental needs a short-term rental license, and non-owner-occupied licenses are capped at 10% of units per blockface. A 12-month moratorium adopted March 9, 2026 pauses new short-term rental licenses except for owner-occupied units, so check with Planning and Zoning before you plan on it. [2][11][14]

Sources (16)
  1. Annapolis City Code § 21.64.010, Accessory dwellings, City of Annapolis (Municode Library). Accessed October 10, 2026.
  2. ADU FAQ, City of Annapolis. Accessed October 10, 2026.
  3. Accessory Dwelling Unit Guide, City of Annapolis Department of Planning and Zoning. Accessed October 10, 2026.
  4. Annapolis City Code § 21.72.010, Terms, City of Annapolis (Municode Library). Accessed October 10, 2026.
  5. Annapolis City Code § 21.48.010, Table of Uses: Residential Zoning Districts, City of Annapolis (Municode Library). Accessed October 10, 2026.
  6. Fees Schedule - FY 2027 (effective July 1, 2026), City of Annapolis (Municode Library). Accessed October 10, 2026.
  7. Land Use Article, § 4-501, Maryland General Assembly. Accessed October 10, 2026.
  8. ADU FAQ for Local Governments (HB 1466), Maryland Department of Planning. Accessed October 10, 2026.
  9. Annapolis City Code § 21.38.030, Bulk regulations, City of Annapolis (Municode Library). Accessed October 10, 2026.
  10. Annapolis City Code § 17.28.090, Permit—Fees—Schedule, City of Annapolis (Municode Library). Accessed October 10, 2026.
  11. Annapolis City Code § 17.44.090, Short-term rentals, City of Annapolis (Municode Library). Accessed October 10, 2026.
  12. Short Term Rental Portal | Citizen Self-Service (CSS), City of Annapolis. Accessed October 10, 2026.
  13. ADU costs FAQ, City of Annapolis. Accessed October 10, 2026.
  14. Ordinance O-40-25, Establishing a 12-Month Moratorium on New Non-owner-occupied Short-Term Rental Licenses (signature copy, adopted March 9, 2026), City of Annapolis City Council. Accessed October 10, 2026.
  15. Land Use Article, § 4-504, Maryland General Assembly. Accessed October 10, 2026.
  16. Planning & Zoning (Staff Directory), City of Annapolis. Accessed October 10, 2026.

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