Queen Anne’s County already allows one accessory guest residence or apartment on a single-family lot, but the County is now considering a new 2026 ADU framework. The current §18:1-48 allows one accessory guest residence/apartment within the principal dwelling or an approved residential accessory structure, caps it at 1,500 square feet, requires Health Department approval when the property is not on public sewer, and requires the owner of the principal dwelling to live on the property. County Ordinance 26-15 would replace that legacy framework with a by-right accessory dwelling unit pathway designed to address Maryland HB 1466/SB 891.
Current status
🟠 TRANSITION — current §18:1-48 remains the published rule while Ordinance 26-15 moves through the 2026 process.
Current baseline: one accessory guest residence/apartment, up to 1,500 sq ft, subject to the conditions below. 2026 proposal: Ordinance 26-15 would create a by-right ADU pathway on the same lot as a principal single-family detached dwelling. Last editorial verification: September 12, 2026.
1. Quick answer: can you build an ADU in Queen Anne’s County?
Potentially, yes. Queen Anne’s County’s currently published zoning code already allows one accessory guest residence/apartment per single-family lot under §18:1-48, provided the current conditions are met. That means Queen Anne’s is not starting from a complete prohibition.
| Issue | Current published Queen Anne’s County rule | 2026 status |
|---|---|---|
| Number of units | One accessory guest residence/apartment per single-family lot. | Current rule remains published. |
| Location | Within the principal dwelling or within an approved residential accessory structure. | Ordinance 26-15 proposes a modern by-right ADU framework. |
| Maximum size | 1,500 sq ft total floor area. | State 75% definition creates an alignment issue for some homes. |
| Owner occupancy | Owner of the principal dwelling must reside on the property. | Do not assume this disappears unless final 2026 text says so. |
| Private septic | Health Department approval required when not on public sewer. | Public-health/sewage capacity remains relevant under state law. |
| Density | Current §18:1-48 says the accessory unit is not included when calculating total allowable units. | Consistent with HB 1466’s density protection. |
The key point is that current law and the 2026 proposal are not the same thing. A homeowner should plan against the current enforceable code while tracking Ordinance 26-15 for changes.
2. What current §18:1-48 actually says
Queen Anne’s County’s current accessory-apartment section is unusually concise. It allows one accessory guest residence/apartment as an accessory residential use per single-family lot and excludes that unit from the calculation of total allowable units.
The current conditions are:
- Same lot: one accessory guest residence/apartment per single-family lot.
- Location: within the principal dwelling or an approved residential accessory structure.
- Size: no more than 1,500 square feet of total floor area.
- Private sewage: if the property is not on public sewer, approval from the Queen Anne’s County Health Department is required.
- Owner occupancy: the owner of the principal dwelling must reside on the property.
This framework comes from the County’s older accessory-apartment approach. It predates Maryland’s statewide HB 1466 framework, which is why Queen Anne’s County is now considering Ordinance 26-15.
3. What Ordinance 26-15 is trying to change
The County’s official September 10 Planning Commission notice describes Ordinance 26-15 as a Planning Commission-sponsored amendment to §18:1-48. Its stated purpose is to allow by right an accessory dwelling unit on the same lot as the principal single-family detached dwelling unit, with requirements intended to address HB 1466/SB 891.
That statement matters for two reasons.
- Queen Anne’s is moving from “accessory apartment” terminology toward the statewide ADU framework.
- The County is proposing by-right treatment. Maryland’s HB 1466 does not force local governments to use a by-right process, so this would be a local policy choice that is more streamlined than a special-exception pathway.
4. The 1,500-sq-ft current cap vs. Maryland’s 75% definition
This is one of the most important issues to watch.
Maryland Department of Planning says HB 1466 defines a qualifying ADU as up to 75% of the size of the primary single-family detached dwelling. MDP further states that local jurisdictions required to authorize ADUs under the state definition may not impose a size cap below that 75% limit.
Queen Anne’s County’s currently published §18:1-48 still uses a fixed 1,500-square-foot maximum. Those standards can produce different results depending on the size of the primary dwelling.
Example: if the accepted primary-dwelling measurement were 2,400 sq ft, 75% would be 1,800 sq ft—greater than the current 1,500-sq-ft local cap.
See our Maryland 75% ADU Size Guide & Calculator for the statewide measurement issue.
5. Detached ADUs are already possible under the current wording—but accessory-structure rules still matter
Current §18:1-48 allows the accessory residence/apartment to be located within an approved residential accessory structure. That means a detached pathway is not new in concept.
However, a detached unit is still affected by the County’s residential accessory-structure rules. The current code generally requires residential accessory structures to be detached from other structures, located at least three feet from property lines, at least six feet from the principal building unless an exception applies, and typically located in a side or rear yard. Additional lot-coverage/area restrictions also vary by lot size and zoning district.
Maryland §4-504 adds an important 2026 constraint on future ADU legislation: a local ADU law may not require side/rear setbacks more restrictive than the jurisdiction’s existing accessory-structure setback standards.
For an actual parcel, do not stop at the three-foot accessory-structure figure. The zoning district, Critical Area status, easements, floodplain, sanitary system and other overlays can still affect the usable location.
6. Septic, well and sewer capacity can decide the project
The current County ADU rule explicitly requires Queen Anne’s County Health Department approval when the property is not served by public sewer.
That is consistent with Maryland’s statewide framework. HB 1466 requires ADU construction to meet public-health and safety standards, including adequate public facilities. Maryland Planning specifically notes that available drinking-water and sewage capacity can remain valid constraints.
For a private-septic property, obtain and review:
- the existing septic permit;
- approved bedroom capacity;
- reserve-area information;
- as-built or system drawings where available;
- any prior repair/expansion records.
Do not assume that a zoning-eligible ADU automatically has sanitary capacity. Use our Maryland ADU Septic & Well Guide before paying for final design.
7. Critical Area properties have an additional ADU rule layer
Queen Anne’s County has extensive Chesapeake Bay Critical Area land, particularly around Kent Island, Grasonville, Queenstown and the County’s shoreline communities. The Critical Area code contains its own treatment for additional dwelling units in the Resource Conservation Area.
Current Critical Area provisions allow one additional dwelling unit per lot or parcel as part of the primary dwelling for density purposes when specified conditions are met. One pathway requires the unit to be within the primary dwelling or within 100 feet of it, no more than 900 square feet of total enclosed area, and served by the same sewage disposal system. Another pathway applies to a unit located within the primary dwelling that does not increase lot coverage and uses the same sewage system.
8. Parking and setbacks: do not assume a new ADU-specific mandate
Maryland’s current statewide law does not prohibit all ADU parking requirements. It says a jurisdiction imposing additional off-street parking specifically for ADUs must first complete a parking study considering construction cost, curb availability, impervious-surface impacts and lot-size variability, and the local law must include a waiver process.
Queen Anne’s County’s current §18:1-48 does not itself state a separate ADU parking-space requirement. We have not verified final Ordinance 26-15 parking language, so this guide does not publish a proposed parking number as if it were current law.
For setbacks, the current accessory-structure rules provide the relevant baseline, but property-specific zoning and overlay review is still required.
See our Maryland ADU Parking Rules and Maryland ADU Setback Guide.
9. Queen Anne’s County mailing address does not always mean County zoning controls
Queen Anne’s County contains eight incorporated municipalities: Barclay, Centreville, Church Hill, Millington, Queen Anne, Queenstown, Sudlersville and Templeville. Maryland Department of Planning lists separate planning contacts and comprehensive plans for these municipalities.
That means a property inside an incorporated town may follow municipal zoning rather than the County’s §18:1-48 framework. Centreville, for example, has been separately developing its own 2026 ADU ordinance work.
10. Queen Anne’s County ADU permit path
| Step | What to verify |
|---|---|
| 1. Resolve jurisdiction | County vs. incorporated municipality. |
| 2. Confirm zoning district and overlays | Use County Property Viewer / zoning determination; check Critical Area and floodplain. |
| 3. Apply the current ADU rule | For County zoning, begin with current §18:1-48 until final Ordinance 26-15 adoption is verified. |
| 4. Verify septic/sewer | Health Department approval is expressly required for properties not on public sewer. |
| 5. Zoning certificate / site plan | Confirm accessory-structure location, setbacks, lot coverage and other site standards. |
| 6. Building permit | Submit under the County’s current residential permitting/building-code process. |
| 7. Inspections / occupancy | Complete required building/trade inspections before occupancy. |
Queen Anne’s County Planning & Zoning currently lists its permitting office at 110 Vincit Street, Suite 104, Centreville. The County also provides a Citizen Self Service portal and current residential building-permit guidance.
11. What to ask Planning & Zoning before paying for plans
- Does County zoning or an incorporated town control this parcel?
- Is §18:1-48 still the currently administered ADU/accessory-apartment rule for this address?
- Has Ordinance 26-15 been introduced, adopted or assigned an effective date since the September 10 Planning Commission review?
- How will the County measure the principal dwelling for the state 75% analysis?
- Does owner occupancy remain required for this project?
- What accessory-structure setback and lot-coverage rules apply in this zoning district?
- Is the property in the Critical Area, floodplain or another overlay?
- Does the existing septic system have approved capacity for the proposed use?
- Is any additional off-street parking required, and if so what parking-study/waiver basis applies?
12. Bottom line
Queen Anne’s County already has an ADU-like accessory-apartment pathway today. The current published rule allows one accessory guest residence/apartment per single-family lot, up to 1,500 square feet, with owner occupancy and Health Department approval for non-public-sewer properties.
Ordinance 26-15 is important because it would modernize that framework around Maryland’s 2026 ADU requirements and explicitly create a by-right ADU pathway. But until final adoption and effective date are verified, homeowners should not treat the proposal as the operative code.
Next step: use the Jurisdiction Finder, then run the Property Feasibility Checker and review the Maryland County & City Rules Tracker.
Primary sources used for this Queen Anne’s County guide
- Queen Anne’s County Code §18:1-48 — Accessory apartments
- Queen Anne’s County — September 10, 2026 Planning Commission notice / Ordinance 26-15
- Queen Anne’s County — 2026 ordinances index
- Queen Anne’s County Critical Area additional-dwelling provisions
- Queen Anne’s County — current building codes
- Queen Anne’s County — permitting and zoning forms
- Maryland Department of Planning — HB 1466 ADU FAQ
- Maryland Land Use §4-504
- Maryland Department of Planning — Queen Anne’s County local planning dashboard
Maryland ADU Guide is maintained by Gijo John as an independent research publication. Proposed legislation is not treated as enacted law. Property-specific zoning, building, environmental-health and utility requirements should be confirmed with the responsible local authority before construction spending.