Hampstead MD ADU Rules 2026: Ordinance 561, 800 Sq Ft Cap, Parking & Sept. 8 Hearing

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Last researched: September 19, 2026. Hampstead is formally creating a municipal accessory dwelling unit framework through Ordinance No. 561. The ordinance was introduced on August 11, 2026, and the Town held a public hearing on September 8, 2026 to discuss the zoning amendment.

Important status: the official Ordinance 561 PDF available through the Town still shows blank passage and effective-date fields. As of this review, we could verify introduction and the September 8 public hearing, but not final passage and effectiveness. Do not treat the proposal as enacted law until Hampstead confirms adoption.

Hampstead ADU proposal at a glance

Question Ordinance 561 proposal
Where ADUs could be allowed Conditional use in any zoning district where a single-family detached dwelling exists as a principal permitted or nonconforming use.
Minimum lot At least 7,500 sq ft and served by public water.
Number of ADUs One per lot.
Owner occupancy Property owner must occupy either the principal dwelling or the ADU.
Detached location Behind the rear building line of the principal dwelling.
Proposed setbacks At least 10 ft from side and rear lot lines.
Proposed size 800 sq ft or 50% of the principal dwelling’s total floor area excluding garages and decks, whichever is less.
Parking Two additional off-street spaces beyond those required for the principal dwelling; parking variance requires Board of Appeals approval and a parking study paid for by the applicant.
Design Architectural compatibility with the principal building and surrounding neighborhood.
Current status Introduced Aug. 11; public hearing Sept. 8; final passage/effective date not verified from the official PDF as of Sept. 19.

Ordinance 561 would create a new § 135-26 for ADUs

The proposed ordinance would create a new § 135-26 titled Accessory Dwelling Unit. It would treat an ADU as a conditional use where a single-family detached dwelling already exists as a principal permitted or nonconforming use.

The proposal also says an ADU may not share a lot with a two-family dwelling, townhouse or multifamily dwelling.

This is broader than a rule limited to one residential district, but “conditional use” does not mean automatic approval. Homeowners should ask the Town what application, hearing, site-plan and review steps are required under the final version.

The proposal requires at least a 7,500-sq-ft lot with public water

Ordinance 561 says the single-family detached dwelling must sit on a lot of at least 7,500 square feet and be served by public water.

That is a significant eligibility screen. A small existing lot or a parcel without public water could fail the proposed ADU rule before size or setbacks are even considered.

Before paying for plans, ask Hampstead whether this minimum-lot requirement remains in the final ordinance and how it applies to legally nonconforming lots.

The proposed 50% / 800-sq-ft cap needs a Maryland-law check

The proposal says an ADU may not exceed 800 square feet or 50% of the total floor area of the principal dwelling, excluding garages and decks, whichever is less.

Maryland’s current ADU framework uses a broader definition. The Maryland Department of Planning says an ADU may be up to 75% of the size of the primary single-family detached dwelling, and covered jurisdictions may not impose a lower local maximum.

For a 1,600-square-foot principal dwelling:

  • 50% equals 800 square feet;
  • Hampstead’s separate 800-square-foot ceiling also stops the unit at 800 square feet; and
  • 75% equals 1,200 square feet.

For a 2,000-square-foot home, the proposal still stops at 800 square feet while 75% is 1,500 square feet.

That does not mean a homeowner should assume a larger unit will automatically be approved. It means the final Ordinance 561 should be checked for changes made after public hearing and for consistency with Maryland’s current state-law framework.

Use our Maryland ADU size guide to understand the state 75% rule, then confirm Hampstead’s final measurement method.

Owner occupancy is central to the proposal

Ordinance 561 would require the property owner to occupy one of the two dwelling units on the property.

The draft goes further and says it would be unlawful to own a property containing an ADU while neither dwelling is owner-occupied. The proposed enforcement language treats that as a municipal infraction with a fine of up to $100, with each day potentially constituting a separate violation.

If your plan depends on eventually renting both the main house and ADU, confirm whether this owner-occupancy requirement survives in the final adopted ordinance before financing the project.

Detached ADUs would have to sit behind the house

The proposal says a detached ADU may only be located behind the rear building line of the principal dwelling.

It also proposes at least 10 feet from both side and rear lot lines.

Those numbers should be checked carefully against Maryland’s current setback rule, which says a local government may not impose side or rear ADU setbacks more restrictive than its existing accessory-structure setbacks.

Hampstead’s existing accessory rules are not uniform

Hampstead’s current accessory-use guidance uses different setbacks depending on the structure:

  • a detached garage: 10 ft from the side lot line and 5 ft from the rear;
  • a storage shed under 150 sq ft: 3 ft from side and rear lot lines;
  • a storage shed of 150 sq ft or more: 10 ft from side and rear lot lines; and
  • a greenhouse or gazebo: 10 ft from the side and 5 ft from the rear.

Because the existing accessory-structure standards vary by structure type, do not assume on your own which one Maryland’s ADU setback limitation uses as the benchmark. Ask Hampstead how the final Ordinance 561 reconciles its proposed 10-ft rear setback with the Town’s existing accessory-use standards.

Current accessory-building rules prohibit habitation

Before an ADU ordinance becomes effective, Hampstead’s existing accessory-use guidance says no accessory building may be used for human habitation. It also says residential accessory buildings generally may not contain full bathroom facilities, except for a pool house.

That is one reason Ordinance 561 matters. The new ADU framework would create a specific zoning exception for a structure that contains sleeping, kitchen and full bathroom facilities.

Homeowners should not assume an existing garage or shed can legally be occupied as a detached ADU before the new law is effective.

The parking proposal is unusually demanding

Ordinance 561 proposes two additional off-street parking spaces for an ADU, on top of the parking already required for the principal dwelling.

The draft says a request for a variance from that parking requirement must go to the Board of Appeals and must be supported by a parking study paid for by the owner/applicant.

Maryland’s current framework separately says jurisdictions imposing additional off-street ADU parking must complete the state-required parking study and provide a waiver process.

Because the Hampstead proposal places the parking-study cost on the individual variance applicant, this is one of the provisions to watch closely in any amended/final version of Ordinance 561.

The proposed ADU must be architecturally compatible

The ordinance says the ADU must be architecturally compatible with the principal building in style, composition, materials, colors and details and should contribute to the surrounding neighborhood’s character.

For a prefab or modular detached ADU, confirm this design requirement before ordering a model. Physical fit and square footage alone may not satisfy the final Town standard.

Accessory structures are already limited by rear-yard coverage

Hampstead’s existing accessory-use guidance says the total area of accessory buildings and structures may not cover more than 50% of the rear yard. Ordinance 561 repeats that same rear-yard coverage limit in the proposed ADU section.

Existing accessory buildings therefore matter. A garage, shed, gazebo or other structure can reduce the remaining rear-yard capacity available for a detached ADU.

The proposal allows attached and detached ADUs

The proposed definition of “Accessory Dwelling Unit” includes a second dwelling:

  • within an existing single-family detached dwelling;
  • attached to the existing single-family dwelling; or
  • in a separate accessory structure on the same lot.

The unit would need independent living facilities for cooking, eating, sanitation and sleeping.

For an attached ADU, the definition also contemplates direct exterior access or access through a common hall with direct outside access.

Hampstead held the public hearing on September 8

The Town’s September 8 public-hearing agenda lists one matter: discussion of Ordinance 561 to amend the zoning code to include and regulate accessory dwelling units.

The ordinance PDF itself says it was introduced August 11, 2026. Its passage, mayoral approval and effective-date lines remain blank in the publicly accessible version reviewed on September 19.

The Town’s current ordinances page lists Ordinance 561 among measures under review or recently passed. Until the Town posts a signed version or codifies the amendment, homeowners should ask staff directly whether the ordinance has been adopted and, if so, what amendments were made after the hearing.

What to ask Hampstead before paying for ADU plans

  • Has Ordinance 561 been finally adopted?
  • What is the effective date?
  • Was the proposal amended after the September 8 public hearing?
  • Does the final ordinance still require a 7,500-sq-ft minimum lot and public water?
  • Does the 50% / 800-sq-ft maximum remain in the final text?
  • How does Hampstead reconcile that cap with Maryland’s 75% framework?
  • Is owner occupancy still required?
  • What side and rear setbacks apply to detached ADUs?
  • How does the final ordinance apply Maryland’s accessory-structure setback limitation?
  • Are two additional off-street parking spaces still required?
  • Has Hampstead completed the state-required ADU parking study?
  • Who pays for any parking study needed for a waiver?
  • What site plan or conditional-use application is required?
  • Can an existing garage or accessory building be converted?
  • What water, sewer and building-permit requirements apply?

Hampstead homeowner checklist

  1. Confirm the property is inside Hampstead municipal limits.
  2. Check the zoning district and whether the single-family house is permitted or legally nonconforming.
  3. Ask the Town for the final signed Ordinance 561.
  4. Confirm the 7,500-sq-ft lot and public-water eligibility rules.
  5. Do not design solely around the draft 800-sq-ft limit.
  6. Determine whether the ADU will be internal, attached or detached.
  7. Verify side/rear setbacks and rear-yard coverage.
  8. Confirm parking and any waiver process.
  9. Check owner-occupancy requirements.
  10. Confirm architectural-compatibility review.
  11. Prepare a survey or site plan before final design.
  12. Do not convert an accessory building to habitation until the Town confirms the ADU law is effective.

Hampstead MD ADU FAQs

Has Hampstead adopted Ordinance 561?

As of this September 19 review, we verified that Ordinance 561 was introduced August 11 and received a public hearing September 8. The official PDF available from the Town still has blank passage and effective-date fields, so final adoption was not verified from that document. Ask the Town for the signed final version.

What size ADU does Ordinance 561 propose?

The proposal uses 800 square feet or 50% of the principal dwelling’s total floor area excluding garages and decks, whichever is less. Maryland Planning says covered jurisdictions may not impose an ADU maximum below 75% of the primary detached dwelling, so the final Hampstead rule should be checked for amendments.

Can Hampstead have a detached ADU?

The proposed definition includes detached ADUs in separate accessory structures. The proposal places a detached ADU behind the rear building line and uses 10-ft side and rear setbacks. Confirm the final enacted standards before designing one.

Does Hampstead require owner occupancy?

Ordinance 561 proposes that the property owner occupy either the principal dwelling or the ADU. The draft also includes a municipal-infraction provision if neither unit is owner-occupied.

How much parking would a Hampstead ADU require?

The proposal requires two additional off-street parking spaces beyond those required for the principal dwelling. A parking variance would require Board of Appeals approval and, under the draft, a parking study paid for by the applicant. Confirm whether that provision remains in the final ordinance.

Can I convert my existing garage today?

Do not assume so. Hampstead’s current accessory-use guidance says accessory buildings may not be used for human habitation and generally may not contain full bathroom facilities. Ask the Town whether Ordinance 561 has become effective and what conversion approvals are required.

Primary sources checked

Maryland ADU Guide is an independent research publication, not the Town of Hampstead, Carroll County, a law firm, architect or contractor. This page distinguishes Hampstead’s existing accessory-building rules from proposed Ordinance 561. Final passage and effective date were not verified from the official ordinance PDF as of September 19, 2026. Confirm the signed final ordinance and parcel-specific requirements with the Town before spending money on design or construction.

YOUR NEXT PRACTICAL STEP

What to do next

Get the final signed Ordinance 561 before choosing an ADU size, parking plan or detached-unit location.

  1. Confirm who reviews the property.
  2. Ask Hampstead whether Ordinance 561 has been adopted and amended after the Sept. 8 hearing.
  3. Gather your zoning district, survey, lot area and utility information.
  4. Continue to the Maryland ADU planning tools.

Planning guidance is not permit approval.