Baltimore County, MD Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Baltimore County, MD, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Governing rule
- BCZR Section 400
- Location
- Rear yard of principal use
- Size rule
- Subordinate to principal structure
- Convert to living space
- Accessory apartment Use Permit
- Coverage cap
- 40 percent of rear yard
Summary
A detached garage is an accessory structure subject to BCZR Section 400: it must be subordinate in area to the house, sit in the rear yard, and meet the 15-foot height and 2.5-foot setback rules. Converting one to living space triggers an accessory-apartment Use Permit.
Section 101 of the Baltimore County Zoning Regulations states that an accessory use or structure is subordinate in area to the principal use or structure on the same lot. Section 400 of the BCZR indicates that an accessory use or structure must be located in the rear yard of the principal use or structure.
Full Breakdown
Baltimore County's Zoning Policy Manual states that under BCZR Sections 101 and 400 an accessory structure must be subordinate in area to the principal structure and located in the rear yard of the principal use. A detached garage follows the same permit, setback, height, and 40-percent rear-yard coverage rules as any accessory building. Converting garage space into a second living quarter with kitchen and bath is treated as an accessory apartment under Section 400.4, requiring a Use Permit (and a Special Hearing if in a detached building), family-only occupancy, and a recorded Declaration of Understanding. Structural or use changes require permits from PAI.
Violations & Fines
Unpermitted conversion to a dwelling unit is a zoning violation; the county may require removal of the second kitchen and restoration of the space, plus fines.
Frequently Asked Questions
Can I turn my garage into an apartment?
Does a garage have to be behind my house?
Sources & Official References
Other rules in Baltimore County
Compare Baltimore County to another location·View the Maryland accessory structures overview
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