Montgomery County · Maryland

Montgomery County MD Building Permits: What Homeowners Actually Need to Know

Montgomery County has some of Maryland's strictest residential permit requirements. This guide covers exact thresholds for sheds, decks, fences, and pools — plus fees, the online application process, and what triggers a zoning review.

See Permit Thresholds How to Apply Online

Montgomery County is one of the most regulated residential jurisdictions in the mid-Atlantic region. That's not a criticism — the county has detailed rules because it has high density, strong environmental protections, and thousands of homeowners making improvements at any given time. But it does mean that projects that wouldn't require a permit anywhere else often require one here.

Building and construction permits in Montgomery County are handled by the Department of Permitting Services (DPS), located at 2425 Reedie Drive, Wheaton, MD 20902. Their main line is (240) 777-0311. Most permit applications are now processed online through the Maryland Permitting and Code Enforcement (PACE) system.

Rockville, Gaithersburg, Takoma Park: If you live inside an incorporated city in Montgomery County, that city handles your permits — not the county DPS. This guide covers unincorporated Montgomery County. Residents of Rockville and Gaithersburg should contact those cities' building departments.

What Requires a Permit in Montgomery County

Storage Shed
Over 120 sq ft
Even exempt sheds under 120 sq ft require a zoning review in some zones. Check your zone first.
Deck
All decks
All decks — attached or freestanding — require a building permit in Montgomery County.
Fence
Over 6.5 ft
Fences 6.5 ft and under typically don't need a building permit, but a zoning permit may be required depending on zone and location.
Swimming Pool
All pools
All in-ground and above-ground pools require building, electrical, and plumbing permits.
Home Addition
All additions
All structural additions require a building permit plus applicable trade permits.
Carport
All carports
All carports require a permit. Temporary fabric carports technically require one too, though enforcement varies.

The Shed Permit Nuance in Montgomery County

The 120 sq ft threshold is one of the lowest in the region, but that's not the only issue with sheds in Montgomery County. Even if your shed is under 120 sq ft, you may still need to go through a zoning review depending on your zone designation. Here's why:

Montgomery County's zoning code places most residential areas in RE, R, TLD, or similar zones, each of which has its own rules about where accessory structures can be placed, how tall they can be, and in some zones, whether they require a permit regardless of size. Before assuming your small shed is fully exempt, confirm your zone at the MC Atlas zoning map and check the rules for your zone in the Montgomery County Zoning Ordinance.

Shed Setback Requirements in Montgomery County

  • Rear yard: 5 feet from rear property line (most residential zones)
  • Side yard: 5 feet from side property line
  • Must be in rear yard: Accessory structures are generally limited to the rear yard — not visible from the street
  • Height limit: 14 feet maximum for most residential accessory structures
  • Distance from primary structure: Must comply with fire separation requirements (typically 6 feet)

One Detail Most Guides Miss: Critical Area

Montgomery County has an extensive stream buffer network — the Environmental Planning Overlay zones along streams and floodplains. If your property is near a stream, wetland, or within the Chesapeake Bay Critical Area, additional environmental review is required before any grading or construction — even for a shed. Check the MC Atlas map for your property's environmental overlays before planning your project.

Deck Permits in Montgomery County

Every deck in Montgomery County requires a building permit — no size exemption exists. This includes:

  • New attached decks
  • Freestanding decks in the yard
  • Replacement decks (same or new footprint)
  • Screened porches and covered decks
  • Deck additions (adding area to an existing deck)
  • Hot tub platforms (if structural)

The Montgomery County deck permit process requires engineered drawings for decks over a certain size or height. For decks under 200 sq ft and under 30 inches high, prescriptive plans based on the IRC span tables are usually accepted. Larger or elevated decks may require stamped engineering drawings, which adds cost but is a firm requirement.

Deck Permit Fees in Montgomery County

Deck permit fees are calculated based on the estimated project value. For a typical homeowner-installed or contractor-built deck, you can expect:

  • Small deck (under 200 sq ft): $100–$200
  • Mid-size deck (200–400 sq ft): $200–$400
  • Large deck with electrical and stairs: $350–$600+

These are estimates. The current fee schedule is published on the Montgomery County DPS website and updates periodically.

Fence Rules in Montgomery County

Montgomery County's fence rules are more nuanced than most neighboring jurisdictions. Here's what you need to know:

  • Fences 6.5 feet and under: Do not require a building permit in most residential zones. However, a zoning conformance review may be required for fences in some zones — contact DPS to confirm for your specific parcel.
  • Fences over 6.5 feet: Require a building permit. The application must include the fence location on a site plan with setback dimensions.
  • Front yard fences: Generally limited to 4 feet in height. Solid front yard fences may require a variance.
  • Corner lot fences: Subject to sight triangle requirements. Fences near road intersections must comply with visibility clearance rules to avoid obstructing driver sightlines.
  • Retaining walls: Retaining walls over 4 feet in height require a permit. Walls under 4 feet may also require one if they are part of a graded slope project.
HOA rules vs. county rules: Many Montgomery County neighborhoods have homeowners associations with additional fence restrictions — height limits, material requirements, approval processes. County permit approval does not override HOA rules. Check your HOA documents before applying for a permit.

How to Apply for a Permit in Montgomery County

Montgomery County uses the Maryland PACE (Permitting and Code Enforcement) system for online applications. Here's the step-by-step process:

  1. Visit the Montgomery County DPS website at montgomerycountymd.gov/DPS and click "Apply for a Permit."
  2. Log in or create an account in the PACE system. You'll need an account to submit applications, upload documents, pay fees, and schedule inspections.
  3. Select your permit type. For accessory structures, choose "Residential Accessory Structure." For decks, choose "Residential Deck." For additions, choose "Residential Addition."
  4. Enter property information. Provide your parcel ID (found on your property tax bill or via the MC Atlas portal) and project address.
  5. Complete the application form. Include project description, estimated value, and contractor information if applicable.
  6. Upload required documents:
    • Site plan showing all property lines, existing structures, and proposed structure with setback dimensions
    • Construction drawings (for decks: framing plan, post/beam schedule, footing details, railing detail)
    • Contractor's state license number and Montgomery County registration number (if using a contractor)
  7. Pay the application fee online. Credit/debit cards are accepted.
  8. Wait for plan review. Residential accessory structure permits typically take 5–10 business days. Decks and additions take 7–15 business days. Corrections are common — respond promptly to avoid further delays.
  9. Download and post your permit card at the job site before any work begins.
  10. Schedule inspections through the PACE system. Required inspection stages depend on the project type.

Common Reasons Montgomery County Rejects Permit Applications

Montgomery County DPS plan reviewers are thorough. These are the most frequent issues that lead to corrections or rejections:

  • Missing setback dimensions on the site plan. The plan must show measured distances from the proposed structure to all property lines — not just approximate locations.
  • Insufficient footing detail on deck plans. Montgomery County requires specific footing size and depth shown on the drawings. "Per IRC" is not sufficient without the actual dimensions.
  • Environmental overlay issue not addressed. If the property has a stream buffer or environmental overlay, additional review is required. Applications that don't acknowledge this are rejected.
  • Contractor not registered with Montgomery County. Contractors must hold both a Maryland Home Improvement Contractor (MHIC) license and be registered with Montgomery County DPS. Out-of-county contractors often miss this.
  • Unlicensed subcontractors on sub-permits. Electrical, HVAC, and plumbing sub-permits must list licensed trade contractors — homeowners cannot self-perform these trades in Montgomery County.
Disclaimer: PermitLocal provides general informational guidance only and is not affiliated with Montgomery County Maryland. Building permit requirements change frequently. Always verify current rules with the Montgomery County Department of Permitting Services at (240) 777-0311 or montgomerycountymd.gov/DPS before beginning any project. This information does not constitute legal or engineering advice.

Frequently Asked Questions — Montgomery County MD

  • A 10×12 shed is 120 square feet — right at Montgomery County's permit threshold. The county's rule is "over 120 sq ft," so a 10×12 technically does not require a building permit. However, you should verify your specific zone designation using MC Atlas, as some zones require a zoning review even for permit-exempt accessory structures. All setback requirements apply regardless of permit status.
  • Yes. Replacing a deck — even with the same size and materials — requires a building permit in Montgomery County. The only maintenance work that doesn't require a permit is replacing individual deck boards in-kind (same material, same size) without changing the structure. Any replacement of posts, beams, joists, ledger board, or the entire deck surface requires a permit.
  • A zoning conformance review is a check by the county's zoning staff to confirm your project meets the setback, height, and placement rules for your specific zone. In Montgomery County, some projects that don't require a building permit (like permit-exempt sheds or standard fences) may still require a zoning conformance review before you can proceed. Call the DPS at (240) 777-0311 and give them your address and project description — they can tell you in minutes whether you need one.
  • Plan review timelines in Montgomery County vary by project complexity and current workload. Simple residential accessory structure permits (sheds, small structures) typically take 5–10 business days. Deck permits take 7–15 business days. Additions and new construction take longer. Montgomery County has an express review program for eligible projects that can shorten timelines — ask about it when you submit your application.
  • Contractors working in Montgomery County must hold a Maryland Home Improvement Contractor (MHIC) license issued by the Maryland Department of Labor and must also be registered as a contractor with Montgomery County DPS. Before hiring any contractor for permitted work, ask for their MHIC license number and verify it at the Maryland DLLR website. A contractor who lacks proper licensing cannot legally pull permits in the county.