MD Permit Guide
Project guide

Do I need a permit for a deck in Maryland?

Almost always, for anything attached to the house or more than a step off the ground. Here's how the rules differ by county.

Maryland counties all build from the same International Residential Code (IRC) through the Maryland Building Performance Standards, and the model IRC exempts only small decks. Counties then amend that exemption, so the answer really depends on where the house is.

The baseline (model IRC R105.2)

A deck is exempt from a building permit only if it meets all of these: no more than 200 sq ft, no more than 30 inches above grade at any point, not attached to the house, and not serving a required exit door. Worcester County's adopted code uses this wording (Resolution 24-01).

County rules we've verified

JurisdictionWhen a deck permit is required
MontgomeryEvery deck supported by footings, at any height. Lighting, hot tubs or spas may also need an electrical permit. Source
Baltimore CountyDecks more than 16 inches above the lowest grade or larger than 120 sq ft. Also any deck, regardless of size, in a historic district, on the Landmarks List, in the floodplain or in the Chesapeake Bay Critical Area. Plans are required at 600 sq ft and up, and sealed plans above 3,000 sq ft. Source
Prince George'sDPIE's enforcement page lists "decks (over 200 sf and over 30 inches above the ground)" among the projects that need permits. (confirm with the office) for decks that meet only one of those limits. Source
WorcesterFollows the IRC baseline above. Source
HowardHoward's amendments exempt only small detached, freestanding decks under 30 inches. We couldn't read the exact size limit cleanly, so (confirm with the office). Source
All other countiesAssume you need a permit for any attached or raised deck, and check your county page: Anne Arundel, Baltimore City, Frederick, Harford, Carroll, Charles, St. Mary's, Calvert, Washington, Wicomico or all 24 jurisdictions.

Other approvals that often apply

Fees

Deck permit fees vary by county and change often. Use your county's official fee schedule, linked from each county page. We don't list deck fees here.

Who can build it?

A contractor building a deck for a homeowner needs an MHIC license. See how to get an MHIC license.

Official sources