ADU rules in Baltimore County, MD — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Baltimore County allows an accessory apartment as a temporary use in an owner-occupied single-family home or accessory building. It requires a Use Permit, must house only family members, cannot have separate meters, and must be renewed every two years.
Under BCZR Section 400.4, an accessory apartment inside the principal dwelling may not exceed one-third of the dwelling's floor area or 2,000 square feet, whichever is less. If placed in a detached accessory building, it may not exceed 1,200 square feet on a lot of one acre or greater, or 800 square feet on a smaller lot, and requires a Special Hearing before the Office of Administrative Hearings. Occupants of the apartment and the main dwelling must be family related by blood, marriage, or adoption, and the unit may not have separate utility meters. A recorded Declaration of Understanding is required.
Use Permit terminates if the apartment is no longer occupied by named family members or the property is sold; unpermitted second units are zoning violations subject to enforcement by PAI.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
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See how Baltimore County's adu rules rules stack up against other locations.
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