The IDDE program consists of outfall inspections, field screening of dry-weather flows, and identifying and eliminating the source of illicit discharges. SWM inspects outfalls to look for signs of illegal discharges to the storm drain system. If dry-weather flow is observed, field screening is conducted to look for significant pollutants. Inspectors use visual observation (sometimes using CCTV video equipment) to track the flow up the storm drain line to attempt to identify the source.