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What Is Stormwater?
Stormwater is excess rain that does not soak into the ground or become absorbed by trees and plants. Instead it runs off into storm drain pipes and flows, untreated, into streams. Most of Rockville's stormwater is a result of impervious surfaces, such as buildings, paved roads and parking lots, compacted soil or gravel, or any other surface that prevents rainfall from percolating into the ground. As the water runs over land, it picks up pollutants like oil, fertilizer, pesticides, pet waste and sediment. These pollutants impact a stream's water quality. As the stormwater increases in volume and speed, it causes stream bank erosion and dumps more sediment into the stream, which harms aquatic insects, fish and animals that depend on the stream for their food and habitat.

Learn how to prevent pollution from entering streams.

There are several ways the City of Rockville helps manage stormwater. The actions help to reduce flooding and protect private property, protect the environment and contribute to happier, healthier communities. 

Aerial photo of Twinbrook Community Center with impervious cover highlighted 

 Police officer

Engineering plan of City of Rockville stormwater facility

 SWM Utility



sediment trap at construction site 

Stream in woods

Dirty filter cartriges in underground stormwater management facility


& Watersheds


Sediment draining into the Chesapeake Bay after a rain storm 

 Stream construction with blaze oarnge fence and tree protection

Kids with trash bags after a stream cleanup 

 Chesapeake Bay


Make a

Environmental Management
General questions, volunteer and incentive programs
Ph: 240-314-8870

Pollution Hotline
Pollution and illegal dumping
Ph: 240-314-8348

Operations and Maintenance

Blocked storm drain
Ph: 240-314-8570

Development review, permitting and City projects
Ph: 240-314-8500