Residential permit rules in Maryland

Representative cities: Baltimore, Annapolis. Covers 16 common home projects.

Verify locally. Maryland enforces the Maryland Building Performance Standards (MBPS — the IBC/IRC/IECC with state amendments) statewide, with limited local amendments. Permits are issued by each city/county. Always verify with your local building department (e.g., Baltimore DHCD or Annapolis Planning & Zoning). Rules below are state/city-level guidance drawn from official sources — always confirm with the issuing building department before starting work. See the county permit authorities to find the right office.

Project	Permit?	Authority	Typical fee	Timeline	Go / No-Go	Key notes
🏠 Accessory Dwelling Unit (ADU)	Permit required	city	Building permit fee set by the city; zoning/use approval also required.	—	Case by case	ADUs require a building permit and local zoning approval. Maryland’s MBPS governs construction; local zoning controls whether an ADU is allowed. Verify with Baltimore DHCD or Annapolis Planning & Zoning.
🪵 Deck / Porch	Conditional	city	Set by the city.	—	Generally allowed	Attached decks and decks over 30 in above grade need a permit. Annapolis publishes deck construction requirements. Exempt: Decks over 30 in above grade generally require a building permit under the IRC (adopted in MD as MBPS).
🧱 Fence / Wall	Conditional	city	—	—	Generally allowed	Most Maryland jurisdictions do not require a building permit for fences, but height and front-yard limits are set locally. Verify with your city.
🛖 Shed / Outbuilding	Conditional	city	—	—	Generally allowed	Detached accessory sheds below the local size threshold are generally exempt. Annapolis publishes shed building requirements. Exempt: Many jurisdictions exempt small detached sheds (commonly under ~120–200 sq ft).
🪜 Basement Finish	Permit required	city	Building permit fee set by the city.	—	Generally allowed	Finishing a basement into habitable space requires permits for egress, framing, electrical, plumbing, and mechanical work.
🚗 Garage / Carport	Permit required	city	Building permit fee set by the city; zoning clearance may be required.	—	Generally allowed	A new attached or detached garage requires a building permit.
☀️ Rooftop Solar PV	Permit required	city	Electrical/structural permit fee set by the city.	—	Generally allowed	Rooftop solar PV requires an electrical and structural permit, reviewed locally.
🌡️ HVAC Replacement	Permit required	city	Mechanical permit fee set by the city.	—	Generally allowed	Furnace, AC, or heat-pump replacement requires a mechanical permit and inspection.
🍳 Kitchen Remodel	Permit required	city	Building permit fee; trade permits billed separately.	—	Generally allowed	A permit is required when relocating plumbing/electrical, moving walls, or changing fixtures.
🛁 Bathroom Remodel	Permit required	city	Building permit fee; trade permits billed separately.	—	Generally allowed	A permit is required when relocating plumbing/electrical, moving walls, or changing fixtures.
🏗️ Room Addition	Permit required	city	Building permit fee based on valuation; zoning and plan review apply.	—	Generally allowed	Room additions require a full building permit, zoning approval, and usually a site plan.
🪟 Window / Door Replacement	Conditional	city	—	—	Generally allowed	Swapping windows or exterior doors in the same opening is generally exempt; enlarging openings requires a permit.
🏘️ Roof Replacement	Permit required	city	Roof-covering permit fee set by the city.	—	Generally allowed	Roof covering replacement is typically permitted. Minor leak repairs may be exempt.
🅿️ Driveway / Parking Pad	Conditional	city	—	—	Generally allowed	A permit may be required where the driveway connects to the street/right-of-way or involves grading/excavation. Verify locally.
🏊 Swimming Pool / Spa	Permit required	city	Building permit fee; barrier fencing required by code.	—	Generally allowed	In-ground and above-ground pools need a permit and barrier fencing per local code.
🧱 Retaining Wall	Conditional	city	—	—	Generally allowed	Height and surcharge determine the threshold. Annapolis requires sheeting/shoring permits for adjacent excavations. Verify with your city.

State-wide sources: Maryland Dept. of Labor — Building Performance Standards (state building code) · Baltimore City — Dept. of Housing & Community Development (permits) · City of Annapolis — Forms, Permits & Licenses