Accessory Structures in Howard County, MD (2026)
6 rules for unincorporated Howard County, Maryland.
Verified from official government sources
ADU Rules
Howard County permits an accessory dwelling unit inside an owner-occupied single-family home. The owner must live in the principal dwelling or the ADU, and a permit from the Department of Planning and Zoning is required. Recent Council Bill 3-2026 expanded ADU options countywide.
Accessory Apartments (ADUs) Allowed in Owner-Occupied Homes
Some RestrictionsHoward County Zoning Regulations § 128.0.13 (Accessory Apartments)
The accessory apartment must be located within an owner occupied dwelling. The owner may occupy either the principal dwelling or the accessory apartment... In all dwellings, an accessory apartment shall occupy no more than one-third of the net floor area of the building, up to a maximum of 1,500 square feet.
ADU Owner Occupancy
Howard County property owners who add an accessory dwelling unit must swear, on the initial rental license application and every renewal, that one of the two dwellings has been and will remain their principal residence. Falsifying that affidavit or moving out entirely can cost $2,500 for a first offense, $5,000 for a second, and permanent loss of the rental license after that.
Howard County ADU Owners Must Attest Residency
Significant RestrictionsHoward County Code § 14.901(l)(1)
(l)Accessory Dwelling Units (ADUs) Specifically. In addition to all other applicable County Codes regulating rental housing:(1)The owner of a property improved with an ADU shall:(i)Maintain a rental license and comply with all applicable provisions of the County Code and Zoning Regulations for either the principal or accessory dwelling on the property if occupied by someone other than the prope...
ADU Rental Restrictions
A Howard County property with an accessory dwelling unit can have only one of its two dwellings under a rental license at a time. The owner has to live in the other one, since a license is only required when a unit is rented to someone outside the owner's immediate family. Renting both units out simultaneously violates the licensing subtitle.
Howard County: Only One ADU Unit Rentable
Some RestrictionsHoward County Code § 14.901(l)(1)-(2)
(1)The owner of a property improved with an ADU shall:(i)Maintain a rental license and comply with all applicable provisions of the County Code and Zoning Regulations for either the principal or accessory dwelling on the property if occupied by someone other than the property owner or a member of the property owner's immediate family; and ... (2)Only one dwelling on the property may hold a rent...
Shed & Carport Rules
A carport in Howard County is an accessory structure subject to Section 128.0 zoning rules. Detached accessory garages and sheds have zero-foot side and rear setbacks on single-family detached lots, while other accessory structures must sit five feet from side and ten feet from rear lot lines.
Carports Are Accessory Structures With Set Setbacks
Some RestrictionsHoward County Zoning Regulations § 128.0 (accessory structure setbacks)
The required setbacks from side or rear lot lines for accessory structures on lots improved by single-family detached dwellings shall be as follows: (1) Detached accessory garages or sheds — 0 feet (2) Other accessory structures (a) Side — 5 feet (b) Rear — 10 feet.
Garage Conversions
In Howard County a detached garage is an accessory structure that cannot contain a full bathroom, full kitchen, or living quarters. Converting a garage into a dwelling requires meeting the accessory-apartment rules under Section 128.0.13 and a Department of Planning and Zoning permit.
No Living Space or Kitchens Allowed in Accessory Structures
Some RestrictionsHoward County Zoning Regulations § 128.0.12.b
Restrictions for accessory structures. Full baths, full kitchens, residential habitation and commercial uses are not permitted in accessory structures.
Tiny Homes
Howard County has no standalone tiny-home zoning category. A permanent tiny dwelling is regulated as an accessory apartment under Section 128.0.13, which requires an owner-occupied property, limits floor area, and requires a Department of Planning and Zoning permit. Tiny houses on wheels are treated as trailers, not permanent housing.
No Separate Tiny-Home Zone; Use Accessory-Apartment Rules
Some RestrictionsHoward County Zoning Regulations § 128.0.13.c
In all dwellings, an accessory apartment shall occupy no more than one-third of the net floor area of the building, up to a maximum of 1,500 square feet.
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