What defines an "illicit discharge" in stormwater systems?

An "illicit discharge" is defined as any unauthorized discharge that negatively impacts water quality. This encompasses a wide range of pollutants and contaminants that can enter stormwater systems without proper treatment or permits, leading to potential harm to aquatic ecosystems and human health. Illicit discharges may include substances like oil, chemicals, and untreated sewage that are not supposed to be discharged into stormwater systems.

The significance of this definition lies in its focus on the negative effect such discharges have on the surrounding environment and water quality. Effective stormwater management strategies aim to minimize or eliminate these types of discharges to protect natural water bodies.

Discharges that meet established quality standards, legally permitted industrial discharges, or discharges from municipal systems do not qualify as illicit because they are regulated and guided by environmental laws and standards designed to maintain water quality. Therefore, it’s crucial for operators to differentiate illicit discharges from compliant ones to ensure proper management and mitigation strategies are in place.