This field guide was developed through the Southern Indiana Stormwater Advisory Committee (SWAC) and serves to educate municipal employees, contractors, and other representatives of the community to increase awareness for identifying and eliminating illicit discharges to our region’s waterbodies. An illicit discharge includes dumping or discharges of foreign materials to the stormwater collection system.  Examples of illicit discharges include oils, grease, trash, dumped yard waste, wastewater (sanitary sewers, greywater, etc), excess soils and sediment (i.e. construction activities), chlorinated pool water, soaps, and other discharges not composed entirely of pure, clean stormwater.  When discharged into the stormwater system, these foreign materials can result in unsafe creeks, rivers and lakes for human recreational activities, as well as cause environmental harm to aquatic species. This field guide contains a number of useful reference materials that municipal employees in various departments can use when completing their day-to-day duties.  The guide serves to increase employee awareness so they are educated about what illicit discharges are, what to look for while in the field, and who to contact when a potential issue is observed.