Overview

What is storm water?

Storm water is generated by runoff from land and impervious areas such as paved streets, parking, and building rooftops immediately following rainfall or as a result of snowmelt. These hardened surfaces do not allow the rainfall to infiltrate into the soil surface, so this rainfall becomes storm water runoff.

Why worry about it?

• Storm water runoff can pick up pollutants such as oil and grease, chemicals, nutrients, metals, and bacteria as it travels across land.

• Heavy precipitation or snowmelt can also cause sewer overflows that may contaminate water sources with untreated human and industrial waste, toxic materials, and other debris.

• Storm water runoff that enters a storm sewer system is discharged UNTREATED into the water bodies we use for swimming, fishing, and drinking water.

• After a dry season, the first flush of storm water can have the same pollutant load as raw sewage. Polluted storm water often affects drinking water sources and can affect human health and increase drinking water treatment costs.