Do I need a permit for accessory dwelling unit (adu) in Unincorporated Charles County?
Yes. In Maryland, accessory dwelling unit (adu) generally requires a permit, and Unincorporated Charles County is no exception.
By October 1, 2026, each county and municipal legislative body must adopt a local law authorizing ADUs on land with a single-family detached home; the law must require ADUs to meet building codes and may not set side or rear setbacks larger than those for accessory structures (Land Use 4-504). State law defines an ADU as a secondary dwelling unit on the same lot as a single-family detached home, no larger than 75 percent of the main home, either detached or attached as an addition (Land Use 4-501). Counties and municipalities may not weaken the Standards' automatic fire sprinkler provisions for one- and two-family dwellings except in narrow cases, such as a property not connected to an electric utility (Public Safety 12-504); ask whether your ADU needs sprinklers.
Documents you may need
- Permit application to the county, Baltimore City, or municipal permit officeRequired
- Site plan with the ADU location, setbacks, lot coverage, and utility connectionsRequired
- Construction drawings with floor plan, foundation, framing, and elevationsRequired
- Energy code compliance documentation (2021 IECC as adopted)Likely required
- Zoning or ADU approval under the local ADU lawLikely required
Possible inspections
- Footing and foundation
- Framing with electrical, plumbing, and mechanical rough-ins
- Insulation and energy
- Final inspection and use and occupancy certificate where issued
Frequently asked questions
- Do I need a permit for accessory dwelling unit (adu) in Unincorporated Charles County?
- Yes. In Maryland, accessory dwelling unit (adu) generally requires a permit, and Unincorporated Charles County is no exception. The documents and inspections sections on this page list what the building department typically asks for.
- Who issues the permit in Unincorporated Charles County?
- The local building department for Unincorporated Charles County handles permitting. This page lists its contact details and online portal. Your mailing city is not always the permitting authority, so confirm the jurisdiction before you apply.
- How do I find out the exact requirements for my project?
- Run the free PermitRoadmap check for your specific project and answers. It returns the likely permits, documents, inspections, and next steps, each linked to its official source.
PermitRoadmap is an independent informational service and is not affiliated with any city, county, state agency, or permitting authority. Results are informational and do not replace confirming requirements with the local permitting authority.