Rockville, MD Environmental Rules: Flood Zones (2026)

Chapter 10 of the Rockville City Code governs floodplain management. The city participates in FEMA's National Flood Insurance Program, making federally backed flood insurance available to property owners. FEMA Flood Insurance Rate Maps (FIRMs) delineate the 100-year floodplain and regulatory floodway along Rock Creek, Watts Branch, and other waterways in the city. Development in the Special Flood Hazard Area (SFHA) requires a floodplain development permit from the city. New construction and substantial improvements must have the lowest floor elevated to or above the base flood elevation (BFE). Structures in the floodway are generally prohibited unless a no-rise certification demonstrates that the project will not increase flood levels. Substantial improvements or repairs exceeding 50 percent of the structure's market value must bring the entire structure into compliance with current floodplain standards. Fill in the floodplain is restricted, and compensatory storage may be required. FEMA has issued updated preliminary FIRMs for Montgomery County reflecting the latest flood risk data. The city also offers flood mitigation assistance through its Flooding Relief program. Contact the Department of Public Works at 240-314-8567 for floodplain inquiries.