--- title: "Baltimore County Garage Permits: Setbacks & Rules | TBG" description: "Baltimore County garage permits: the 120 sq ft threshold, rear-yard placement, 2.5 ft setbacks, the 15 ft height limit, attached garages and plans." url: https://thebrettgroup.com/guides/garage-permit-baltimore-county/ last_updated: 2026-11-02 --- [TBG](https://thebrettgroup.com/) / [Home Remodeling](https://thebrettgroup.com/remodeling/) / Baltimore County garage permits Local guide · Baltimore County · October 2026 # Do you need a permit to build a garage in Baltimore County? Yes. Baltimore County requires a permit for any accessory building over 120 square feet, and an attached garage is an addition that always needs one. Here is where a detached garage can go, how big and tall it can be, and what to submit. Get matched with a builder who knows this Short answer Do I need a permit to build a garage in Baltimore County? Yes. Any accessory building over 120 square feet needs a permit, and an attached garage is an addition that always needs one. On historic, floodplain or Critical Area lots, any size needs a permit. Updated November 2026 · Official sources - **120 sq ft**: Larger accessory buildings need a permit - **2.5 ft**: From side and rear lot lines - **15 ft**: Height limit for a detached garage - **Rear yard**: Behind the back wall of the house | Project | Baltimore County permit? | | --- | --- | | Detached garage over 120 sq ft | Yes, residential accessory structure permit | | Attached garage | Yes, addition permit | | Any garage or shed on a historic, floodplain, Critical Area or landmark lot | Yes, at any size | | Electrical or plumbing work | Yes, pulled by a licensed electrician or plumber | | Converting a garage to living space | Yes, addition and alteration permit | ## 1. Attached or detached? Baltimore County treats anything attached to the house as an addition, not an accessory building, so an attached garage must meet the setbacks for the house itself. The county's zoning policy manual also treats a garage connected to the house by an open deck, porch or carport as part of the house. Detach it and it can be reviewed under the more flexible accessory building rules. ## 2. Where a detached garage can go | Rule | Detached garage or accessory building | | --- | --- | | Location | Rear yard, behind the rear foundation wall of the house | | Side and rear setback | 2.5 ft from the lot line | | Within 5 ft of a lot line | One-hour fire-rated wall with no openings on that side | | Alley | At least 15 ft from the alley centerline | | Corner lot | In the half of the lot farthest from the side street | | Height | 15 ft maximum | | Coverage | No more than 40% of the rear yard | | Size | No larger than the footprint of the house | Anything outside these limits, such as a side-yard garage or a taller carriage house, needs a zoning variance. Accessory buildings aren't allowed on a vacant lot; the lot has to be combined with the one the house sits on. ## 3. What to submit For a detached garage, the county asks for a signed accessory structure letter and a site plan; lots on a well or septic system follow the county's groundwater site plan requirements. Construction plans are required at 1,000 square feet and over, and garages over 400 square feet need footings below the frost line. The county requires a Maryland Home Improvement Commission licensed contractor for the work. For an attached garage, the addition permit needs a site plan, construction plans at 600 square feet or more, an energy code selection form and the contractor's MHIC license number. ## 4. Fees, inspections and timing The county charges a $75 residential application fee plus a permit fee set by structure type and size (accessory structures under or over 1,000 square feet, additions under or over 600 square feet). Fees are calculated by the county and paid online. Inspections are booked through the online portal, with the approved plans on site. A permit expires one year after it's issued, or after six months if work hasn't started. Electrical and plumbing work need their own permits by licensed trades; in Baltimore County, plumbing permits require a county-licensed plumber. ## 5. Historic, floodplain and waterfront lots On a landmark property or in a historic district, in the floodplain or in the Chesapeake Bay Critical Area, every accessory building needs a permit regardless of size. In the 100-year floodplain, the garage must be anchored and vented. See our [Baltimore County permit guide](https://thebrettgroup.com/guides/baltimore-county-building-permits/) for historic district review. ## 6. Converting a garage Turning an attached garage into a bedroom, office or family room is an alteration that needs a permit, with construction plans if it creates a bedroom. On a well and septic lot, adding a bedroom also means showing the septic system can handle it. An in-law apartment inside a single-family house needs a county use permit. ## Where this comes up most [Towson →](https://thebrettgroup.com/remodeling/towson/) · [Catonsville →](https://thebrettgroup.com/remodeling/catonsville/) · [Perry Hall →](https://thebrettgroup.com/remodeling/perry-hall/) · [Parkville →](https://thebrettgroup.com/remodeling/parkville/) · [Timonium and Lutherville →](https://thebrettgroup.com/remodeling/timonium-lutherville/) · [Arbutus →](https://thebrettgroup.com/remodeling/arbutus/) ## Projects we match - [Additions](https://thebrettgroup.com/remodeling/additions/anne-arundel/): Bump-outs, second stories and in-law suites. - [New custom homes](https://thebrettgroup.com/remodeling/custom-homes/anne-arundel/): Build on your lot with a registered Maryland home builder. - [Decks & exteriors](https://thebrettgroup.com/remodeling/decks-exteriors/anne-arundel/): Decks, porches, siding, windows and roofing. - [Kitchen remodels](https://thebrettgroup.com/remodeling/kitchen/anne-arundel/): Layouts, cabinets, counters and full gut renovations. ## Common questions ### Do I need a permit to build a garage in Baltimore County? Yes. Any accessory building over 120 square feet needs a permit, and an attached garage is an addition that always needs one. On historic, floodplain or Critical Area lots, any size needs a permit. ### How close to the property line can a detached garage be in Baltimore County? 2.5 feet from the side and rear lot lines, in the rear yard behind the house. A wall within 5 feet of a lot line needs a one-hour fire rating with no openings. ### How tall can a detached garage be in Baltimore County? 15 feet. A taller accessory building needs a zoning variance. ### How big can a detached garage be? No larger than the footprint of the house, and all accessory buildings together can cover no more than 40% of the rear yard. ## Official sources [Baltimore County PAI: Residential accessory structures](https://www.baltimorecountymd.gov/departments/pai/application/accessory-structure) · [Baltimore County PAI: Additions and alterations](https://www.baltimorecountymd.gov/departments/pai/application/addition-alteration-modification) · [Baltimore County Zoning Policy Manual (2023)](https://www.baltimorecountymd.gov/files/Documents/CountyCouncil/Resolutions%202023/r03623.exhibit%20B.pdf) · [Baltimore County Bill 49-24 (building code)](https://countycouncilweb.s3.amazonaws.com/Bills%202024/b04924.pdf) · [Baltimore County: Building fees](https://www.baltimorecountymd.gov/files/departments/permits-approvals-and-inspections/documents/buildingprocessfee.pdf) · [Baltimore County: Building inspections](https://www.baltimorecountymd.gov/departments/permits/buildinspec) This guide is general information, not legal or engineering advice. Rules and maps change; confirm the requirements for your property with the permit office before you design or sign a contract. ## Related guides [- **Baltimore County permits**: Baltimore County sets clear size limits for decks, fences and sheds, and stricter rules for historic,…](https://thebrettgroup.com/guides/baltimore-county-building-permits/) · [- **Flood-zone guide**: Before you price a big remodel near the water, find out whether the 50% rule applies. It decides whether…](https://thebrettgroup.com/guides/flood-zone-renovation-anne-arundel/) · [- **Critical Area guide**: If your home is within 1,000 feet of tidal water, the Chesapeake Bay Critical Area rules shape what you can…](https://thebrettgroup.com/guides/building-near-the-water-critical-area/) · [- **House types guide**: Most of the county's homes fall into a handful of types, and each one has a remodel that pays off and a…](https://thebrettgroup.com/guides/remodeling-anne-arundel-house-types/) · [- **Materials guide**: Salt air, humidity, summer heat and freeze-thaw winters are hard on houses near the Bay. Choosing the right…](https://thebrettgroup.com/guides/chesapeake-coastal-building-materials/) · [- **Septic guide**: If your home is on septic, two things shape your project: whether a nitrogen-reducing (BAT) system is…](https://thebrettgroup.com/guides/septic-upgrades-bay-restoration-fund/) [All local guides →](https://thebrettgroup.com/guides/)