Greensboro MD ADU Rules 2026: 500/800 Sq Ft Legacy Rules, Parking & HB 1466

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Last researched: September 19, 2026. Greensboro already has accessory-apartment language in the Land Development Ordinance linked from the Town’s current Planning, Zoning & Codes Enforcement page. The problem is that the published ordinance contains two different sets of standards for essentially the same secondary dwelling use. One section uses a 33% / 800-square-foot formula and requires four total off-street parking spaces; another performance-standard section limits the unit to 500 square feet, internal conversion only, requires owner occupancy and says no additional parking is required.

Homeowner takeaway: Do not design a Greensboro ADU around a single number pulled from the older ordinance PDF. Ask the Town’s Planning Department which accessory-apartment provisions currently control and whether Greensboro has adopted an HB 1466-compliant amendment since the ordinance document linked on the Town website. Maryland now requires covered jurisdictions to authorize ADUs consistent with the state’s 75% definition by October 1, 2026.

Greensboro ADU planning snapshot

Question What we verified
Local zoning authority Greensboro has its own Planning, Zoning & Codes Enforcement Department and municipal zoning process.
Current public zoning source The Town’s current Planning page links its Land Development Ordinance, which is labeled amended through August 8, 2018.
Accessory apartment allowed? Yes. The use table lists accessory apartments in several zoning districts, subject to the applicable standards and approval type.
Section 10.21 size rule The unit must be inside the principal single-family dwelling and may not exceed the lesser of 33% of the dwelling’s gross livable floor area or 800 sq ft.
Section 16.02 size rule A separate performance-standard section says the second unit may not exceed 500 sq ft, subject to a limited exception for structural or historic-building reasons.
Parking Section 10.21 calls for four total off-street spaces; Section 16.02 says no additional off-street parking is required. Ask the Town which current standard controls.
Owner occupancy Section 16.02 says either the primary unit or accessory unit must be owner-occupied.
Garage conversion Section 16.02 says the accessory rental unit may not be created through conversion of an existing garage.
House age Section 16.02 says the house must be at least five years old before conversion.
Critical Area The published ordinance contains a separate Critical Area ADU standard, including conditional treatment in the Resource Conservation Area.
2026 state-law issue Maryland Planning says covered jurisdictions may not cap ADUs below 75% of the size of the primary detached dwelling.

Greensboro’s published ordinance has two different accessory-apartment standards

The Town’s current Planning page directs residents to its Land Development Ordinance for zoning and development requirements. That document is labeled amended through August 8, 2018. Within it, accessory apartments appear in more than one section.

Section 10.21, under Accessory Uses, says an accessory apartment is permitted within a single-family dwelling if the listed conditions are met. Among those conditions:

  • the ADU must be inside the principal single-family dwelling on its own lot;
  • the unit may not exceed the lesser of 33% of the gross livable floor area or 800 square feet;
  • an outside entrance cannot be placed on the front wall of the principal structure;
  • home occupations are prohibited within the accessory apartment; and
  • a minimum total of four off-street parking spaces is required for the primary and accessory dwelling, subject to a narrow exception described in the ordinance.

But Section 16.02, “Uses with Performance Standards,” contains another accessory-apartment section with materially different conditions.

Section 16.02 is more restrictive in several ways

The performance-standard section defines an accessory apartment as a second dwelling unit that is part of a one-family detached dwelling. It then says:

  • either the primary unit or accessory unit must be owner-occupied;
  • the unit may be created only through internal conversion of existing living area, basement or attic;
  • an existing garage may not be converted;
  • the house must be at least five years old before conversion;
  • only one entrance may be located on the front of the house unless additional front doors existed before conversion;
  • no additional off-street parking is required; and
  • the second unit may not exceed 500 square feet, except where the stated structural/historic-building exception is approved.

Because the Town’s linked ordinance contains both sets of provisions, a homeowner should not decide on their own that the 800-square-foot section or the 500-square-foot section is the “real” rule. Ask the Zoning/Planning staff how the provisions are reconciled today and whether later amendments supersede either section.

The old 500- and 800-sq-ft limits also need an HB 1466 check

Maryland’s 2025 ADU law changed the statewide baseline. The Maryland Department of Planning says an ADU is a secondary unit on the same lot as a primary single-family detached dwelling and may be up to 75% of the size of the primary dwelling. MDP further says jurisdictions required to authorize ADUs may not impose a local maximum below that 75% threshold.

That means Greensboro’s published 500-square-foot limit and its 33% / 800-square-foot formula cannot simply be assumed to remain the final 2026 maximum for a new application.

For example, on a 1,600-square-foot primary dwelling:

  • 33% is about 528 square feet;
  • the older performance-standard cap is 500 square feet; and
  • 75% is 1,200 square feet.

This does not guarantee approval for a 1,200-square-foot ADU. It means Greensboro must implement a local law consistent with Maryland’s definition and other state requirements. Ask the Town for the current controlling ordinance before selecting a floor plan.

Use our Maryland ADU size guide to understand the 75% framework, then confirm Greensboro’s measurement method for the primary dwelling.

Maryland’s law also supports attached and detached ADUs

Greensboro’s older accessory-apartment language is focused heavily on internal conversions. Maryland’s current HB 1466 FAQ says the state definition includes an ADU that is attached as an addition or located in a separate structure from the primary dwelling. Jurisdictions may also permit wholly internal units.

That creates another question for Greensboro’s final implementation: how the Town will treat a new detached backyard ADU, a detached garage conversion, or an attached addition when the older performance-standard language only contemplated internal conversions.

Do not assume the older “no garage conversion” sentence automatically answers a 2026 detached-ADU application. Ask whether the Town has adopted or is applying a newer HB 1466-compliant section.

Parking is particularly important because the published ordinance contradicts itself

Section 10.21 says a minimum total of four off-street parking spaces must serve the principal dwelling and accessory unit. Section 16.02 says no additional off-street parking is required for the accessory rental unit.

Maryland’s new ADU law adds a separate limitation: a jurisdiction may not impose additional off-street parking requirements on ADUs without first completing the parking study required by HB 1466, and any local law requiring additional ADU parking must provide a waiver process.

For a current Greensboro application, ask three direct questions:

  1. Which parking provision applies now?
  2. Has Greensboro completed the state-required parking study if it is imposing additional ADU parking?
  3. What is the current parking-waiver procedure?

Greensboro also has a Critical Area ADU provision

The Town’s published Land Development Ordinance includes a separate Chesapeake Bay Critical Area section. Its use table lists accessory dwelling units as permitted in the IDA and LDA when allowed by the underlying zoning district, and conditionally permitted in the Resource Conservation Area.

For RCA property, the ordinance includes a supplemental standard allowing one additional dwelling unit as part of a primary dwelling under stated conditions involving the same sewage-disposal system, location relative to the primary dwelling, enclosed area and lot coverage.

Greensboro also discussed updating its Critical Area ordinance in 2025. Town Council minutes from April 17, 2025 show state representatives specifically discussing an optional ADU provision for Resource Conservation Area property while introducing Ordinance 2025-O-1.

If your property is near the Choptank River or otherwise within the Critical Area, ask the Town which version of the Critical Area ordinance now applies before deciding where to place a detached unit.

Greensboro is updating its long-range planning documents

The Town is currently working on the Greensboro 2050 Comprehensive Plan, replacing the plan adopted in 2010. The Town describes the new plan as addressing current land-use, housing, infrastructure, climate and environmental issues.

A comprehensive plan is not itself an ADU permit rule, but the timing matters: Greensboro is updating its planning framework at the same time Maryland requires municipalities with planning and zoning authority to adopt HB 1466-compliant ADU laws by October 1, 2026.

We did not find a separately titled 2026 HB 1466 ADU ordinance

For this September 19, 2026 research pass, we checked Greensboro’s current Planning, Zoning & Codes Enforcement page, its linked Land Development Ordinance, 2025 Critical Area meeting materials, the 2026 Town Council agenda materials surfaced through the Town website, and Maryland Planning’s current HB 1466 guidance.

I did not find a separately titled 2026 Greensboro ordinance clearly identified as the Town’s final HB 1466 ADU implementation law. That does not mean none has been adopted or is pending. The Town’s Planning Department specifically advises property owners to contact staff because regulations and conditions can vary by project.

Before relying on any of the older accessory-apartment numbers above, ask the Town for the current signed ordinance or codified section.

What to ask Greensboro before paying for plans

  • What ordinance currently governs ADUs in Greensboro?
  • Has the Town adopted its HB 1466-compliant ADU law?
  • Which accessory-apartment section currently controls: § 10.21, § 16.02, a later amendment, or some combination?
  • What is the current maximum ADU size?
  • How does the Town measure the primary dwelling for Maryland’s 75% rule?
  • Are internal, attached and detached ADUs all allowed?
  • Can an existing garage or accessory structure be converted now?
  • Does owner occupancy remain required?
  • Does the five-year house-age rule remain in effect?
  • Which parking requirement currently applies?
  • Has Greensboro completed an ADU parking study?
  • What parking-waiver process applies?
  • What side and rear setbacks apply to a detached ADU?
  • Is the parcel in the Chesapeake Bay Critical Area?
  • What water/sewer, building and occupancy permits are required?

Greensboro homeowner checklist

  1. Confirm the property is inside Greensboro municipal limits.
  2. Check the zoning district on the Town zoning map.
  3. Ask Planning & Zoning for the current ADU ordinance or controlling code sections.
  4. Do not design solely around the old 500- or 800-square-foot numbers.
  5. Confirm whether the project is internal, attached, detached or an accessory-building conversion.
  6. Verify the current size calculation.
  7. Confirm owner-occupancy and house-age rules, if any.
  8. Verify setbacks, height and lot coverage.
  9. Ask which parking provision applies and whether a waiver is available.
  10. Check Critical Area status.
  11. Confirm water/sewer and building-permit requirements.
  12. Do not make a non-refundable construction commitment until the Town confirms the current rules in writing.

Greensboro MD ADU FAQs

Does Greensboro allow accessory apartments?

Yes. The Land Development Ordinance currently linked by the Town contains accessory-apartment provisions and lists the use in several zoning districts. The exact current standards should be confirmed because the published ordinance contains two different accessory-apartment sections and Maryland’s 2026 ADU requirements now apply.

Is the Greensboro ADU limit 500 sq ft or 800 sq ft?

The published ordinance contains both figures. Section 10.21 uses the lesser of 33% of the house or 800 square feet, while Section 16.02 says 500 square feet with a narrow exception. Ask the Town which current provision controls and whether a newer HB 1466 amendment has superseded both.

Can I build a detached ADU in Greensboro?

Maryland’s current ADU definition includes separate detached structures, while Greensboro’s older general accessory-apartment language focuses on internal conversions. Confirm the Town’s current HB 1466 implementation before assuming a detached unit is approved under the older code.

Does Greensboro require extra ADU parking?

The published code is inconsistent: § 10.21 calls for four total off-street spaces, while § 16.02 says no additional off-street parking is required. Maryland now also requires a parking study and waiver process if a jurisdiction imposes additional ADU parking requirements.

Can I convert my garage into an ADU?

The older § 16.02 performance standard says an accessory rental unit may not be created by converting an existing garage. Because Maryland now requires local laws to authorize ADUs consistent with the state framework, ask Greensboro whether that older restriction remains in the current law.

Who should I contact about a Greensboro ADU?

Start with the Town of Greensboro Planning, Zoning & Codes Enforcement Department at 111 S. Main Street, Greensboro, Maryland 21639. The Town lists 410-482-6222 and recommends that property owners contact Planning staff before undertaking development or construction work.

Primary sources checked

Maryland ADU Guide is an independent research publication, not the Town of Greensboro, Caroline County, a law firm, architect or contractor. This page reports the differing standards in the Land Development Ordinance currently linked by the Town and compares them with Maryland’s current HB 1466 guidance. Confirm the current signed ordinance and parcel-specific requirements with Greensboro before spending money on design or construction.

YOUR NEXT PRACTICAL STEP

What to do next

Ask Greensboro which accessory-apartment section is controlling today before choosing a size or parking plan.

  1. Confirm who reviews the property.
  2. Ask the Town for the current HB 1466 ADU ordinance or controlling code sections.
  3. Gather your zoning district, survey, utility and Critical Area information.
  4. Continue to the Maryland ADU planning tools.

Planning guidance is not permit approval.