The quality of stormwater can vary widely depending on factors such as location, the surfaces it runs over, and the surrounding environment. As stormwater flows across urban areas, it often picks up pollutants like oil, chemicals, heavy metals, trash, and sediments from streets, parking lots, and rooftops. This can make it contaminated and unsuitable for direct reuse without treatment.
In rural or natural areas, stormwater may have fewer pollutants but could still carry sediment, organic matter, or pesticides. Because of these contaminants, stormwater typically requires filtration and treatment before it can be safely used for non-potable purposes, such as irrigation or industrial cooling. The quality of stormwater is also influenced by the first flush, which refers to the initial runoff after a rainstorm, often containing the highest concentration of pollutants.
