ADU Rules in Rockville, Maryland

Rockville is an incorporated city of about 68,000 and the county seat of Montgomery County, Maryland, approximately 15 miles northwest of Washington DC. As an incorporated city, Rockville has its own Zoning Ordinance separate from Montgomery County's regulations — use the City of Rockville's permit process for properties within Rockville city limits. Home to significant biotech and federal agency presence (including NIST, FDA's White Oak Campus is nearby), Rockville is a major DC suburban employment center.

Rockville vs. Montgomery County

• Rockville (city): Incorporated city with its own Zoning Ordinance — use Rockville's permit process
• Montgomery County: Separate county government — covers unincorporated areas outside Rockville
• Verify which jurisdiction your property falls in

City of Rockville Zoning Ordinance

The City of Rockville Zoning Ordinance governs all land use within Rockville city limits.

Maryland ADU Rules

ADU rules in Maryland are set by each county and municipality. Verify current ADU requirements with the City of Rockville Planning and Development Services.

Permitted ADU Types

Per Rockville Zoning Ordinance (verify current standards):

• Accessory apartments: Within or attached to primary structure
• Detached ADUs: In eligible residential zones
• Garage conversions: Subject to zoning standards

Verify current provisions with Rockville's Department of Community Development.

Size Limits

Per Rockville Zoning Ordinance:

• Maximum floor area per zone
• Lot coverage restrictions apply

Setbacks

Per Rockville residential zone:

• Rear: Minimum setback
• Side: Minimum setback

Chesapeake Bay Watershed — Stormwater

Rockville is in the Chesapeake Bay watershed. The city has stormwater management requirements for new construction, including ADUs.

Historic Districts

Rockville has historic districts and a historic Main Street area. Properties in historic districts may require review.

Permit Process

1. Verify jurisdiction: Confirm your property is within Rockville city limits (not unincorporated Montgomery County)
2. Verify zoning: Rockville Department of Community Development
3. Stormwater/environmental review: May apply
4. Historic review: If in a historic district
5. Submit plans: Rockville Permit Center
6. Building permit and inspections
7. CO: Required before occupancy

Contact

City of Rockville Department of Community Development 111 Maryland Avenue, Rockville, MD 20850 Phone: (240) 314-8200 Website: rockvillemd.gov

Disclaimer: Rockville is an incorporated city separate from Montgomery County. ADU rules are evolving following Maryland's 2024 statewide legislation. Verify current standards with the City of Rockville before starting any project.