Rockville, MD Environmental Rules: Stormwater Management (2026)

The City of Rockville holds an MS4 permit under the NPDES program issued by the Maryland Department of the Environment (MDE). This permit requires the city to manage stormwater runoff to protect water quality in Rock Creek, Watts Branch, and other tributaries of the Potomac River watershed. Development projects that disturb 5,000 square feet or more of land area or move 100 cubic yards or more of soil must submit stormwater management plans for review and approval. Plans must conform to the latest version of MDE's Stormwater Design Manual and incorporate environmental site design (ESD) practices to the maximum extent practicable. ESD techniques include rain gardens, bioretention facilities, permeable pavement, green roofs, and infiltration practices. Rockville requires stormwater management concept approval before detailed engineering plans are submitted. All stormwater facilities must be maintained by the property owner or a designated maintenance entity. The city conducts inspections of private stormwater management facilities to ensure ongoing compliance. Stormwater permits are applied for online through the city's permitting portal. Contact the Department of Public Works at 240-314-8567 for stormwater inquiries.