Rockville, MD Accessory Structures: Shed Rules (2026)

Under Chapter 25 of the Rockville City Code (Zoning Ordinance), sheds and other accessory buildings must be located in the rear yard of single-unit detached homes. A building permit is required for all sheds regardless of size. The maximum footprint for any single accessory building is 750 square feet, and it cannot exceed the footprint of the main building. The combined footprint of all accessory buildings on a single lot is capped at 1,000 square feet. Maximum rear yard building coverage is 15 percent in R-150, R-200, and R-400 zones and 25 percent in all other residential zones. The minimum setback from any lot line is 3 feet. The maximum height at the minimum setback is 12 feet. Buildings taller than 12 feet must be set back an additional 3 feet for each additional foot of height, up to 15 feet. Accessory buildings may reach a maximum of 20 feet with no further setback increase, but cannot exceed the height of the main dwelling. Height is measured to the roof peak from the lowest point of finished grade. Contact the Inspection Services Division at 240-314-8247 for permit applications.