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Codes, exemptions & field inspections

Build to the adopted code. Verify every exception.

This guide translates the available agency record into a preconstruction checklist for structural scope, minor work, and inspection release. The adopted code and the issuing official control when a field condition is disputed.

Regulatory framework

The code baseline for St. Mary's County.

The 2024 St. Mary's County Building Code incorporates the 2021 International Building Code, 2021 International Residential Code, 2021 International Energy Conservation Code, 2021 International Existing Building Code, and 2021 International Swimming Pool and Spa Code, with county and Maryland amendments. It also references the Maryland State Plumbing Code and 2018 International Fuel Gas and Mechanical Codes as applicable under the ordinance. All new permit applications are reviewed under the 2026 National Electrical Code beginning July 1, 2026.

Inspection lane

Use the county's permit status system for application tracking. County construction/site inspections can be requested through the online Inspection Request Form; requests are normally answered within 48 hours. For an immediate health or safety threat call DPW&T at 301-475-4200 ext. 3531. Building, electrical, mechanical, plumbing, and fire inspection requirements vary by permit and must be completed before the Certificate of Occupancy; inspections also verify zoning, stormwater, critical-area, and forest-conservation compliance.

Minor-work playbook

Understand what may be exempt—and what is not.

The county code exempts one-story detached tool/storage sheds, playhouses, or similar non-habitable accessory structures no larger than 120 square feet when outside the floodplain; fences no higher than 7 feet; retaining walls no higher than 4 feet unless supporting a surcharge or certain liquids; certain grade-level sidewalks and driveways; painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work; and some tanks and temporary stage sets. Exemption does not authorize work that violates other laws or ordinances, and a garage or carport still needs a permit even if under 600 square feet, although it may be exempt from building-code inspections.

Field rule

A permit exemption generally addresses one narrow construction trigger. It does not automatically waive zoning, land-use, floodplain, shoreline, fire, energy, electrical, utility, septic, or right-of-way requirements. Obtain written confirmation when the project involves a new structure, structural alteration, change in occupancy, or concealed work.

Inspection pipeline

Keep the work visible at every release point.

  1. 1

    Request with lead time

    Use the county's permit status system for application tracking. County construction/site inspections can be requested through the online Inspection Request Form; requests are normally answered within 48 hours. For an immediate health or safety threat call DPW&T at 301-475-4200 ext. 3531. Building, electrical, mechanical, plumbing, and fire inspection requirements vary by permit and must be completed before the Certificate of Occupancy; inspections also verify zoning, stormwater, critical-area, and forest-conservation compliance.

  2. 2

    Preserve access

    Do not cover framing, reinforcement, wiring, piping, damp-proofing, or life-safety work until the required inspection has been completed and documented.

  3. 3

    Close the record

    Retain the approved plans, inspection approvals, correction responses, and final certificate or occupancy release with the property file.

Contractor verification

Verify the builder before the contract is signed.

Use the state licensing system to verify active registration, trade credentials, bond status, and liability coverage where available. Match the legal business name to the proposal and permit application.

Verify contractor ↗

Planning reference

Keep the parcel rules beside the building plans.

A building permit is only one part of statutory compliance. Check the local zoning, ordinance, map, or land-use reference before finalizing setbacks, height, lot coverage, access, drainage, or accessory structure placement.

Open planning reference ↗

Source trail

Official sources for this profile

Use these direct agency or licensing links to confirm current instructions before you file, pay, or schedule work. External pages control if their information differs from this directory.

Agency websiteOpen official source ↗Permit portalOpen official source ↗Application instructionsOpen official source ↗Fee scheduleOpen official source ↗Planning or zoning referenceOpen official source ↗Contractor license lookupOpen official source ↗

Project questions

Frequently asked questions for St. Mary's County

Who handles permitting for this jurisdiction?

St. Mary's County Department of Land Use & Growth Management, Permit Services Division is the identified county-level authority for this profile. Confirm that the property is in its service area before filing.

How should I begin an application?

Begin with the online permit gateway listed in the application guide. If the portal does not recognize the address or project type, contact 301-475-4200 ext. 1500 (Permit Services); 301-475-4200 ext. 1580 (Inspections); 301-475-4670 (lot grading/drainage).

How long might review take?

N/A - the county publishes permit-counter hours and electronic status tracking but no single standard plan-review timeline. Inspection-request submissions are expected to receive a response within 48 hours.

How are inspections scheduled?

Use the county's permit status system for application tracking. County construction/site inspections can be requested through the online Inspection Request Form; requests are normally answered within 48 hours. For an immediate health or safety threat call DPW&T at 301-475-4200 ext. 3531. Building, electrical, mechanical, plumbing, and fire inspection requirements vary by permit and must be completed before the Certificate of Occupancy; inspections also verify zoning, stormwater, critical-area, and forest-conservation compliance.

Which codes and exemptions should I review?

The 2024 St. Mary's County Building Code incorporates the 2021 International Building Code, 2021 International Residential Code, 2021 International Energy Conservation Code, 2021 International Existing Building Code, and 2021 International Swimming Pool and Spa Code, with county and Maryland amendments. It also references the Maryland State Plumbing Code and 2018 International Fuel Gas and Mechanical Codes as applicable under the ordinance. All new permit applications are reviewed under the 2026 National Electrical Code beginning July 1, 2026. The county code exempts one-story detached tool/storage sheds, playhouses, or similar non-habitable accessory structures no larger than 120 square feet when outside the floodplain; fences no higher than 7 feet; retaining walls no higher than 4 feet unless supporting a surcharge or certain liquids; certain grade-level sidewalks and driveways; painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work; and some tanks and temporary stage sets. Exemption does not authorize work that violates other laws or ordinances, and a garage or carport still needs a permit even if under 600 square feet, although it may be exempt from building-code inspections.

Field sequencing matters

The inspector needs to see the work at the right moment.

Code compliance is not only a plan-review exercise. Footings, reinforcement, framing, fireblocking, wiring, piping, insulation, weather protection, and life-safety systems each have points where the work must remain accessible. Build the inspection calendar into the trade schedule instead of treating it as a final administrative step.

When a project qualifies for a narrow minor-work exemption, keep a written explanation of why it qualifies and confirm that related zoning, utility, fire, energy, or environmental rules do not create a separate approval requirement.

Closeout file

Keep the approved plan set, inspection approvals, correction responses, contractor license verification, final certificate, and any occupancy release together. A clean record protects the owner, builder, lender, insurer, and future buyer.