The most common pollutants include sediment, pathogens, nutrients and metals – such impaired waters need Total Maximum Daily Loads (TMDLs) – this resource provides examples of what states have done to identify/address/implement via National Pollutant Discharge Elimination System (NPDES) stormwater permitting system. 

TMDLs identify the total pollutant loading that a waterbody can receive and still meet water quality standards.