Image showing how rainfall runoff becomes stormwater

Stormwater is rainfall that does not evaporate or infiltrate into the ground.

Common stormwater pollutants

Urban Stormwater - Issues

Urban stormwater transports sediment, debris and pollutants to our waterways

What is it?  Stormwater is rainfall that does not infiltrate into the ground or evaporate.  Stormwater runoff can occur in any landscape.  In urban areas it is largely due to impervious surfaces (rooftops, sidewalks, and roads) as well as areas of vegetation removal or compaction.

So what's the issue?  Rainfall striking natural and man-made surfaces dislodges and transports pollutants (oils and trash), sediment, pathogens, and nutrients (lawn clippings, fertilizers and pet waste) and carries them in stormwater runoff. In communities where the sanitary and storm sewers are separate, stormwater is conveyed through ditches and piping and discharged untreated into creeks, streams or other waterbodies we use for recreation and to provide drinking water.   Untreated stormwater results in impaired water quality which can have negative environmental, ecological, and economic impacts. 

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