What is defined as "illicit discharge"?

An illicit discharge refers to any discharge that is not entirely comprised of stormwater. This definition captures a wide range of contaminants that may enter the stormwater system, including pollutants from industrial processes, sewage, or other unauthorized sources. The goal of identifying and regulating illicit discharges is to protect water quality and ensure that the stormwater management system functions as intended without being tainted by these harmful substances.

Water from permitted industrial sources is often regulated and monitored, ensuring that it meets specific discharge standards, and therefore may not be classified as illicit. Rainwater runoff from agricultural land typically falls within the scope of natural stormwater management practices unless it carries specific pollutants that violate regulations. Similarly, discharges from natural water bodies are not considered illicit as they occur naturally and are part of the hydrological cycle.

Understanding the nature of illicit discharges is crucial for effective stormwater management, compliance with regulations, and maintaining the integrity of water bodies.