Rockville, MD Environmental Rules: Grading & Drainage (2026)

Chapter 19 of the Rockville City Code regulates grading and drainage for development and redevelopment projects. A grading permit is required for any earth-moving activity that disturbs 5,000 square feet or more of land area or moves 100 cubic yards or more of soil. Grading plans must demonstrate adequate gradients to prevent standing water on lawns for more than 24 hours after rainfall (48 hours in designated drainage courses and swales). All grading must provide positive drainage away from building foundations and openings. No permanent cut or fill slope steeper than 3:1 is allowed in lawn maintenance areas. Surface drainage must not be redirected onto adjacent properties without appropriate easements. The city enforces grading standards through plan review and field inspections during construction. Retaining walls exceeding 4 feet in height require engineered design and a separate building permit. Drainage connections to the city's storm sewer system require approval from the Department of Public Works. WSSC Water standards also apply to grading near water and sewer infrastructure. Contact the Department of Public Works at 240-314-8567 for grading and drainage inquiries.