Rockville, MD Environmental Rules: Stormwater Management (2026)
Key Facts
- Disturbance threshold
- 5,000 sq ft or more
- Residential threshold
- 2,000 sq ft new impervious
- Other property threshold
- 250 sq ft new impervious
- Permit
- Required before system installation
- Standard
- MDE Stormwater Design Manual
Summary
Any Rockville project disturbing 5,000+ square feet, or adding as little as 250 square feet of new pavement on non-residential land, must provide on-site stormwater management.
(a) Except as otherwise provided, the SWM provisions of this chapter and the regulations apply to any development that: (1) Involves five thousand (5,000) square feet or more of disturbed area; (2) Creates or replaces two thousand (2,000) square feet or more of impervious area on an single unit detached dwelling, townhouse or semi-detached dwelling lot; (3) Creates or replaces two hundred fifty (250) square feet or more of impervious area on property other than a single unit detached dwelling, townhouse or semi-detached dwelling lot; or...
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 17 Update 1).
Full Breakdown
Rockville's Department of Public Works requires stormwater management (SWM) for development that disturbs 5,000 square feet or more of land, adds 2,000 square feet or more of new impervious area on a single-unit, townhouse or semi-detached lot, adds 250 square feet or more of new impervious area on any other property, or needs federal or state approval to alter a floodplain, City waterway, stream buffer or wetland. Projects must use environmental site design to the maximum extent practicable, follow the MDE Stormwater Design Manual, and obtain a SWM permit before any system is installed: no permit for new impervious area may issue until the related SWM permit is issued.
Violations & Fines
Disturbing land or adding impervious area above the SWM thresholds without an approved SWM concept, construction plan and permit is prohibited; installing a stormwater system before permit issuance is a separate, standalone violation.
Frequently Asked Questions
When does a Rockville project need a stormwater management plan?
Which City department runs Rockville's stormwater program?
Sources & Official References
Other rules in Rockville
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Stormwater Management in Nearby Cities
How other cities in Montgomery County handle stormwater management.