| Project | Baltimore County permit? |
|---|---|
| Deck more than 16 in above grade and over 120 sq ft | Yes |
| Fence 42 in or taller | Yes |
| Shed or accessory building over 120 sq ft | Yes |
| Retaining wall over 3 ft | Yes |
| Basement finishing with structural, bedroom or trade work | Yes |
| Addition, structural change, new bedroom or kitchen, enclosed porch | Yes |
| Plumbing, gas or electrical work | Yes, trade permit |
| Siding and roof repair | Not required, unless the house is historic or a landmark |
| Smaller decks, fences and sheds on a historic, floodplain or Critical Area lot | Yes, at any size |
1. Who issues permits
Baltimore County's Department of Permits, Approvals and Inspections (PAI) issues building, plumbing and electrical permits for the whole county, including Towson, Catonsville, Arbutus and every other unincorporated community. Its office is in the County Office Building at 111 West Chesapeake Avenue in Towson, open weekdays 8:30 to 4:30 (410-887-3900). Since November 2021, applications are filed online, and the county answers "do I need a permit?" questions at 410-887-3953.
2. Decks, fences, sheds and walls
- Decks need a permit when they are more than 16 inches above grade and larger than 120 square feet. Under 600 square feet, a site plan is enough; 600 square feet or more needs construction plans.
- Fences need a permit at 42 inches or taller, and can't be built in access easements.
- Sheds and accessory buildings over 120 square feet need a permit. They go in the rear yard, at least 2.5 feet from side and rear lot lines, no taller than 15 feet, with frost footings over 400 square feet.
- Retaining walls over 3 feet need a permit, with extra documents at 4 feet and up.
3. Basements, additions and remodels
Finishing a basement needs a permit when you move a bearing wall, make structural changes, add a bedroom, excavate, or run any plumbing, gas or electrical work. Additions, structural alterations, a new bedroom or kitchen, and enclosing a porch or deck all need a building permit. Sealed plans from a Maryland-licensed design professional are required for additions of 600 square feet or more, new bedrooms, second-floor additions and structural work, along with a 2021 energy code form.
4. Who can pull the permit
Contractors need a Maryland Home Improvement Commission license. Baltimore County also licenses its own plumbers and gasfitters: only a Baltimore County-licensed plumbing or gasfitting contractor can apply for those permits. State-licensed master electricians must register with the county; homeowners making minor wiring repairs in their own home are exempt from the license requirement.
5. Historic, floodplain and waterfront lots
Properties on the county Landmarks List or in one of its historic districts, such as Lutherville, Relay, Sudbrook Park or Glyndon, need a Certificate of Appropriateness from the Landmarks Preservation Commission for exterior changes, and a permit even for work that normally wouldn't need one. The Commission meets the second Thursday of most months. In the floodplain, county rules (Bill 6-24) require two elevation certificates by a licensed surveyor before a permit is closed. Within 1,000 feet of tidal water, Chesapeake Bay Critical Area limits on lot coverage and tree clearing apply. Near Martin State Airport, an airport zoning permit may also be needed.
6. Codes and inspections
Baltimore County builds to the 2021 International Residential, Building and Energy Codes and the 2023 National Electrical Code. Schedule inspections through your online account by 2 p.m. the business day before. Ask PAI for the current fee when you apply. Inside Anne Arundel County, see our Anne Arundel permit guide; in Howard County, our Howard County guide.
