Do You Need a Permit to Build a Deck in Montgomery County, MD?

Cross the District line into Bethesda and the deck you were planning becomes a different application. Same deck, same drawings, same builder. Different county, different authority, different rules about what you have to submit and how long you’ll wait.

Montgomery County requires a building permit for a deck. The county’s Department of Permitting Services is clear about it, and sitting low to the ground doesn’t get you out of it.

There’s no height exemption

DPS states that “a building permit is required for all decks that are supported by footings regardless of the height above grade.” The overview on the same page puts it more broadly still: “a building permit is required for all decks regardless of the height above grade.”

So a platform a step off the lawn behind a Rockville split-level is in the same category as a raised deck off the back of a house in Potomac. If it’s a deck on footings, it needs a permit.

The shortcut for a single-span, single-level deck

Here’s the part worth knowing before anyone starts drawing. Montgomery County publishes a standard document, the Residential Deck Details, and DPS says it “may be used in lieu of construction plans for single-span, single-level decks.”

Two words in that sentence do the deciding: “single-span” and “single-level.” They are the county’s terms, and the Deck Details drawing set is what defines them, so if you are not certain your design fits, that is worth settling with DPS, or with whoever is drawing the deck, before the application goes in rather than after.

What the page does spell out is where the shortcut stops. Decks with “roofs, screened porches, hot tubs, or other additional loads” are outside it, and a roof puts you back into full construction plans.

If any part of your deck involves a structural detail the standard drawing doesn’t show, that’s the moment to involve someone who can produce plans rather than trying to force the project into a document it was never meant to cover.

How fast it actually moves

Eligible applications go through the county’s Fast Track process, which DPS says “can result in a permit in as little as a few hours.” The page doesn’t say what share of decks qualify, so it is worth asking which route yours is on.

A regular review is slower but still predictable. For adequately prepared applications, DPS says “it may take up to 17 days to issue the permit.” The phrase doing the work in that sentence is “adequately prepared,” because the clock the county quotes applies to an application that arrives complete.

Applications go in online. DPS says “you must apply online using DPS eServices,” so there is no counter to visit.

Three things the permit doesn’t settle

A building permit answers one question: whether the structure meets the county’s construction requirements. It leaves three others open, and each one has caught homeowners out.

Zoning. DPS notes separately that “you will also need to make sure that that your project conforms to Zoning requirements.” Setbacks and lot coverage are a different check from the structural one, and a deck can be perfectly built and still sit where it isn’t allowed.

Well and septic. The county states that “properties with an individual well and septic system will have additional requirements.” If your property has either, find out what those requirements are before you fix the deck’s footprint, because the location of a septic field can decide where the deck can go.

Covenants and deed restrictions. DPS says that “many of the subdivision and developments in Montgomery County have private deed restrictions and covenants” regulating construction, and that “the County does not enforce covenants and deed restrictions.” A county permit is not permission from a homeowners association. They are two separate approvals, the county will not referee between them, and DPS points you to your homeowners or civic association for that side of it.

Two extras that sit outside the building permit

The county page flags two further permissions that are easy to miss.

The first is electrical. DPS says that “for decks constructed with stairway illumination or hot tubs, spas, etc., an electrical permit may be required.” Lights in the stair risers or power for a hot tub mean a second application, not a line on the first one.

The second is municipal. DPS notes that “you may also need a permit or other permission if you live in a Montgomery County municipality that requires it.” Parts of the county sit inside incorporated municipalities that run their own permitting, so the county is not automatically the only authority your address answers to. It is worth checking which applies to yours before assuming the county permit is the whole story.

Who actually pulls the permit

You can apply in your own name as the homeowner. Where a contractor is doing the work, DPS “strongly suggests that the contractor be listed on the permit as the party responsible for the work.”

There’s a licensing rule attached to that. DPS states that “a contractor must have a Maryland Home Improvement Contractor’s (MHIC) license to obtain a permit.” It’s worth knowing the rule exists before you agree terms with anyone, because it’s a question with a documented answer rather than a matter of opinion.

After the permit comes through

The permit is where the county’s involvement starts rather than ends. The DPS process lists three inspection points, footing, framing and final, and points to a separate schedule for the full list. Each is a hold point, so the build sequence has to leave room for them.

Inspections are booked rather than dropped in on. DPS says they “shall be requested at least 24 hours prior to the inspection date,” which is worth putting in the schedule rather than discovering on the morning the concrete is ready.

Two paperwork requirements run alongside the work. “The permit must be kept on site and available to DPS inspectors until the project is completed,” and “hard copies of the drawings and documents must be available for the inspector at the job site.” A PDF on somebody’s phone is not what the county asked for.

How this differs from the District

If you’ve already read up on deck permits for a DC property, set that knowledge aside. The two jurisdictions genuinely differ.

DC runs a dedicated Deck Permit service type for a one-level deck under 500 square feet on a single or two-family home, leans on its own Deck Guide, and asks for a plat with the application. Montgomery County asks for a permit on every footing-supported deck regardless of height, offers the Deck Details document in place of plans for single-span single-level decks, and can turn a Fast Track application around in hours. We’ve covered the District’s version in our guide to deck permits in Washington, DC.

The practical upshot for anyone building in Bethesda, Rockville, Potomac or Gaithersburg: get the county’s requirements from the county, not from a neighbor’s experience across the line.

If you’re planning a deck in Bethesda, Rockville, Potomac or Gaithersburg, the county’s rules shape the design itself and not only the paperwork: whether a deck stays single-span and single-level is a design decision, and it carries through the whole project. It’s worth making deliberately rather than by accident. If you’re weighing materials at the same time, we looked at whether composite decking is worth it for Gaithersburg homeowners, and custom deck installation is where decisions like these get settled.